Stick Welding Polarity Explained: DCEP vs DCEN vs AC

A fabricator grabs a box of 3/32-inch E7018 rods, clamps the ground lead on the workbench, and starts a fillet weld on a 1/4-inch bracket. The bead looks fine, but the joint is cold in the middle and the slag is a stubborn, crusty blanket that takes three passes to chip off. Twenty minutes later, after a quick check of the rod box, the same bracket gets welded on the other polarity — and the slag pops off in one piece and the root actually fuses. Nothing about the machine changed; only the polarity did. That single switch is one of the most misunderstood controls in stick welding, and it is the difference between a weld that passes inspection and one that quietly cracks.

The Polarity Problem Nobody Warns You About

A fabricator drops a box of 3/32-inch E7018 rods on the bench, clamps the ground lead to a worktable, and runs a fillet weld on a 1/4-inch bracket. The bead looks reasonable at first glance. Then the slag comes off and the middle of the joint turns out to be cold, with a crusty blanket of slag that takes three passes to chip away. Same rods, same machine, same amperage setting. Flip the polarity and the slag pops off in one piece and the root actually fuses. Nothing changed except which way the current was running.

That switch is the most misunderstood control in stick welding. It is also one of the cheapest to get right, and one of the most expensive to get wrong on a code job or a bracket that has to hold.

So what is the right polarity?

Here is the short answer before anything else: for most stick welding today, the correct setting is direct current electrode positive (DCEP), also called reverse polarity. On a DC machine, that means the electrode holder lead is on the positive terminal and the work clamp is on the negative terminal, so the current flows from the base plate into the electrode. ESAB notes that DCEP is the default polarity for most stick electrodes, because that is how the modern low-hydrogen and rutile coatings are designed to burn. If you own a modern DC inverter and you grabbed an E7018, that is almost certainly the setting you want.

What goes wrong when you get it backwards

Welders actually hit two failure modes, and they look very different from each other.

• Running DCEN on a rod that calls for DCEP. The arc feels cold and erratic, the puddle is sluggish, and the root may not fuse into the base metal at all. The electrode tends to stub out before it should, meaning it stops melting long before the joint is filled. Slag coverage tends to be thick and stubborn, just like the bracket in the story above.
• Running DCEP on a rod that calls for DCEN. Now the consumable electrode is taking the hot side of the arc, so the rod melts and lays down far too quickly. You get spatter, a fat uncontrolled bead, poor puddle control, and on light-gauge work a real chance of burning straight through the joint before you finish it.

Why the confusion is so widespread

Three things are stacked on top of each other here.

First, the polarity is not written on the front of the rod. It is buried inside the electrode classification number. AWS A5.1 encodes coating type and usable current type plus polarity in the final digits of a designation such as E7018, so the answer is printed on the box if you know how to read it. Most beginners never learn that code, so they guess.

Second, the instructions on the box get skimmed. Each pack of electrodes states which polarity to use, and as ESAB points out, the rods will only weld successfully when you follow the polarity recommendation on the packaging. That print is the source of truth, not a forum post.

Third, the vocabulary is genuinely confusing. Reverse versus straight, positive versus negative, EP versus EN, DCEP versus DCEN. And the lead you move is the electrode holder lead, not the work clamp, which is the opposite of what most people assume.

One more thing to clear up early: polarity only means something on a DC machine. On an old transformer-type AC welder the current reverses direction continuously, so there is no positive or negative terminal to choose between. Setting polarity simply is not a task on that machine.

By the end of this guide you should be able to decode any AWS electrode classification, pick the right polarity for any common rod, change polarity on your own machine safely and correctly, and recognize the symptoms of a polarity mistake in the puddle and the slag.

One honest caveat before we go further. Polarity is a real control, and getting it wrong is genuinely damaging. But for most jobs it is not the biggest variable in the outcome. Amperage set within the electrode’s approved range, joint preparation, and electrode condition (especially moisture pickup in a low-hydrogen rod) account for far more weld defects than polarity does. Get the polarity right, then work through the rest of the setup before you blame the switch again.

What Polarity Actually Is: Anode, Cathode and Where the Heat Goes

Before you can pick the right polarity, you need the vocabulary. Polarity is one of those topics where the words themselves trip people up, because the same idea carries four different names depending on who you ask. So let’s build it from scratch.

First: current type, then polarity

These are two separate ideas that get tangled constantly.

Current type describes what your machine produces: direct current (DC), where electrons travel one way only, or alternating current (AC), where direction reverses many times per second.

Polarity describes which way that current flows on a DC circuit. It only exists on DC. An old AC transformer has no polarity to speak of, because its current reverses constantly. If someone tells you “set the polarity on your AC machine,” either they are confused or they mean a machine with a polarity switch for DC work.

In a DC circuit, electrons flow from the negative terminal to the positive terminal. Conventional current is drawn the other way, but electrons are what matter in an arc, because they are the particles actually bombarding the surfaces. So “electrode positive” means the electrode holder lead is wired to the positive terminal, the work clamp is on the negative terminal, and electrons stream from the work clamp, up through the work, across the arc, and into the electrode. That electron stream gives you two distinct DC polarities, and each makes a different part of the arc the hot, active surface.

The three parts of a welding arc

According to the University of Alberta’s Fundamentals of Welding Engineering handout, a welding arc has three main parts:

• The arc column — the glowing plasma channel between the electrode tip and the work. This is the visible arc you watch, and it is the hottest part of the whole process.
• The anode — the positive surface of the arc.
• The cathode — the negative surface of the arc, the region where electrons are emitted from the electrode tip.

Which surface is the anode and which the cathode depends entirely on which way the current runs. In electrode positive, the consumable electrode is the anode (the normal arrangement for GMAW and MIG). In electrode negative, the electrode is the cathode (normal for GTAW/TIG, where the tungsten is negative and heat concentrates on the work).

Here is the crucial bit. Heat does not split evenly between the two poles. In a DC arc, roughly one third of the heat is generated at the negative pole (cathode) and roughly two thirds at the positive pole (anode), as described in the Army welding manual’s chapter on the welding arc. That asymmetry is the entire reason polarity matters in stick welding.

The plain-English version of where the heat goes

Take the 2/3 to 1/3 split and apply it to the two DC settings.

On DCEP (electrode positive), the electrode is the anode, so most of the heat lands on the consumable rod. The rod melts faster, lays down faster, and burns through faster. Less heat goes into the base metal from the pole itself.

On DCEN (electrode negative), the work is the anode, so most of the heat lands on the workpiece. More base metal melts, and the rod runs cooler and slower.

That is the whole concept in one sentence: DCEP makes the consumable the hot side, DCEN makes the workpiece the hot side.

Treat it as a starting point, not a law. Final penetration is also driven by amperage, travel speed, arc length, electrode diameter, coating chemistry and the arc’s mechanical “dig” (the plasma jet plus electromagnetic pinch that pushes molten metal into the joint). A cellulosic rod like E6010 on DCEP gives deep root penetration. A low-hydrogen rod like E7018 on DCEP is often used for fill and cap passes with deliberately shallow penetration. Same polarity, different result, because the coating and the job differ. We dig into that in the DCEP versus DCEN comparison later.

The naming trap

How the leads are actually connected

Polarity is decided purely by which terminal each lead is bolted to. There are two leads: the electrode holder lead, which carries the rod, and the work clamp lead, which connects the job to the machine.

On DCEP, the electrode holder goes to the positive (+) terminal and the work clamp sits on the negative (−) terminal. On DCEN, it is reversed: the electrode holder goes to negative (−) and the work clamp to positive (+).

So “changing polarity” in stick welding is physically just moving the electrode holder lead from one terminal to the other. That is worth stating plainly, because many welders believe polarity is buried in a menu somewhere and cannot be changed by hand. On most modern multiprocess inverters it is both: a selector switch, a menu setting, or a lead swap, depending on the machine. We cover all the variations step by step in the section on switching polarity on your own welder.

Quick reference: the three settings side by side

Setting	Electrode holder	Work clamp	Main physical effect	Who uses it
DCEP (electrode positive, reverse)	Positive (+)	Negative (−)	About two thirds of arc heat lands on the rod: fast melt, fast burn-through, deeper base-metal heating through arc dig	Default for most stick work on modern inverters: E7018, E6013, E7016, E7024 and similar
DCEN (electrode negative, straight)	Negative (−)	Positive (+)	About two thirds of arc heat lands on the workpiece: more melt into the plate, slower rod consumption, softer and wider arc	Electrodes specified DCEN such as E6012 and E7027, plus thin or delicate work where arc control matters
AC	Alternates both ways	Alternates both ways	Arc reverses every half cycle, so the weld sees a blend of both conditions; penetration sits between the two DC extremes	Dirty or oxidized surfaces, farm and field repair, and jobs with a recurring magnetic arc blow problem

If you take one thing from this section, make it the heat split. Two thirds at the anode, one third at the cathode, and that is why flipping polarity changes how fast your rod burns and how fast your plate melts. Once that clicks, the rest of the polarity discussion, including which setting each all-position welding rod demands and how to get the most out of stick welding, becomes far easier to reason through.

Reading Your Electrode: How AWS A5.1 Numbers Encode Polarity

Polarity is printed on the rod box in small type that most welders never read. The good news is that the electrode classification number already carries that answer. Once you can decode a designation like E7018, you will never have to guess whether the electrode holder lead belongs on the positive or the negative terminal, and you will be able to read any rod, from any manufacturer, in about three seconds.

Anatomy of an Electrode Number

An AWS A5.1 designation is a short code, and each character has a specific job. Taking E7018 apart:

• E — the consumable is an arc welding electrode, not a brazing rod or a cutting electrode.
• 70 — minimum tensile strength of the deposited weld metal, in thousands of psi. 70 means 70,000 psi. That is why an E6010 is a 60,000 psi electrode and an E7018 is a 70,000 psi electrode. These are laboratory minimums on standard test coupons, not a guarantee about your finished joint.
• 1 — the usable welding positions. 1 is all position, 2 is flat and horizontal only, 3 is flat only, and 4 is flat, horizontal, vertical down and overhead, according to the AWS classification reference at Lincoln Electric.
• 8 — the coating type, and this is the digit that carries current type and polarity.

Notice that E6010 and E7018 share the same position digit (both all position) and differ in strength and coating. The position digit tells you where you can hold the gun, not how to set the machine.

The Final Digit: Coating, Current and Polarity

This is the table worth printing and sticking next to your machine. It maps the last digit of the AWS number to coating chemistry and usable current:

Final digit	Coating type	Usable current and polarity
0	Cellulose sodium	DC+ only (DCEP)
1	Cellulose potassium	AC or DC+
2	Titania sodium	AC or DC- (DCEN)
3	Titania potassium	AC, DC+ or DC-
4	Iron powder titania	AC, DC+ or DC-
5	Low hydrogen sodium	DC+ only
6	Low hydrogen potassium	AC or DC+
7	High iron oxide / iron powder	AC, DC+ or DC-
8	Low hydrogen potassium / iron powder	AC or DC+

The formal AWS A5.1 Table 8-1 listings agree with that digit logic: E6010 is DCEP only, E6011 is AC or DCEP, E6012 is AC or DCEN, E6013 is AC or DC in either polarity, E7024 is AC or DC in either polarity, and E7027 is AC or DCEN. For a printable one-page version with common rods side by side, the electrode polarity chart is a handy shop reference.

Worked Decoding: E6013 and E7018

E6013. E for electrode. 60 for a 60,000 psi minimum tensile strength. 1 for all position. 3 for high titania potassium, which the table allows on AC, DC+ or DC-. In plain English: this rod is polarity-proof. Hook the leads up either way and it will run, which is exactly why it is the standard training and shop-floor general purpose rod. If you want to see how position ratings translate into real work, the all position welding rod guide breaks down the common families and where each one behaves best.

E7018. E for electrode. 70 for a 70,000 psi minimum tensile strength. 1 for all position. 8 for low hydrogen potassium or iron powder, usable on AC or DC+ only. So this is a DCEP rod on DC power, and a fact worth respecting: run it DCEN and you are outside the electrode’s rated operating range, which affects arc behaviour, slag formation and the mechanical properties of the deposit.

The Rule That Outranks Every Chart

Classification tables are excellent for learning and for decoding an unfamiliar rod in a hurry. They are not the last word on a specific product in your hand. Coatings get reformulated, and some manufacturers print a narrower or broader polarity recommendation than the generic AWS digit implies.

One more thing worth knowing: the logic above applies to carbon steel electrodes under AWS A5.1. Stainless, nickel alloy and cast iron electrodes live in their own A5.x tables with slightly different numbering conventions, though the same principle applies. Follow the data sheet for those. And if you are still building your foundation, it is worth reading up on why SMAW still wins in so many shops before you buy a box of rods.

Electrode-by-Electrode Polarity Guide with Amperage Ranges

Bookmark this section. Every common stick electrode below lists its designed polarity, arc behaviour on that setting, and the amperage range to run it at. Set the machine before you strike an arc.

Polarity assignments come from the AWS A5.1 electrode classifications, and the chart published by Baker’s Gas cross-checks the box in your hand. “Either polarity” means both work; a single listing means that is the only correct choice.

Cellulosic Electrodes: E6010, E6011 and E6012

E6010 is a high cellulose sodium electrode and it is DCEP only. Do not run it DCEN or on AC. It gives deep penetration with minimal joint preparation, making it the classic root-pass rod for pipe, and works well vertical-up because that penetration helps tie-in. The trade-off is a rough bead, heavy slag and heavy spatter. Set it at 75 to 125 amps on 1/8 inch per the Miller stick setting calculator. It is an all-position rod, a staple of any all-position welding rod guide.

E6011 is the potassium version of the same coating family and it runs on AC or DCEP. Potassium gives it a lower ionization energy, producing a steadier arc on 50/60 Hz line-frequency AC and an easier strike than the 6010. That is why it stays popular in oil and gas field work, on thinner sheet metal, and with old transformer power supplies.

E6012 is titania sodium. AWS A5.1 lists it as AC or DCEN, and it is commonly sold as a DCEN rod even though some older boxes still say DC+. It gives a smooth, low-spatter bead with good slag control, and is often used on galvanized or lightly rusted sheet.

Rutile Electrodes: E6013 and E7014

E6013 is titania potassium and the most forgiving rod you can buy: AC, DCEP and DCEN all work. It is the general purpose choice with shallow to medium penetration, minimal spatter and self-releasing slag, and the standard training rod because it works on every power supply in all positions. Set it at 80 to 130 amps on 1/8 inch or 40 to 90 amps on 3/32 inch.

E7014 is iron powder titania, rated for AC or DC either polarity. Compared with the 6013 it gives medium penetration, a smoother bead and faster deposition, which makes it a favourite for quick fillet work.

Low Hydrogen Electrodes: E7015, E7016 and E7018

E7015 is low hydrogen sodium and is DC+ only. E7016 is the potassium version and runs on AC or DC+. Both are used when hydrogen cracking is the concern.

E7018 is low hydrogen potassium with iron powder, rated for AC or DCEP, and it is the structural workhorse of stick welding. The arc is quiet, spatter is low, and impact properties are the best at low temperature. It handles high strength steels, plate, shipyards, pressure vessels and piping, and meets the most severe X-ray quality standards. Downsides: heavy slag and real moisture sensitivity, so keep it sealed. Run it at 110 to 165 amps on 1/8 inch or 65 to 100 amps on 3/32 inch. More on matching filler metals to base material in our alloy steel welding electrode guide.

Iron Powder Electrodes: E7024 and E7027

E7024 is iron powder titania, rated for AC or DC either polarity. It has the fastest deposition rate of any common stick rod and lays down a smooth bead, a favourite for flat and horizontal fillet work. It is flat and horizontal fillet only, so it is no help overhead or vertical. Set it at 140 to 190 amps on 1/8 inch.

E7027 is the high iron powder electrode, rated DCEN, and it gives very high deposition on flat and horizontal positions.

Non-Carbon Electrodes

E308L stainless electrodes run on DCEP or AC. Nickel chloride cast iron (Ni-Cl) rods also run on DCEP or AC, and the nickel alloy core gives them their distinctive crack-resistant bead on cast iron.

Amperage and Polarity Settings Together

Set amperage and polarity together. The ranges below come from the Miller stick setting calculator, which also lists penetration and position.

Electrode	1/8 inch	3/32 inch	Penetration	Positions	Polarity
E6010	75–125 A	—	Deep	All	DCEP only
E6013	80–130 A	40–90 A	Low	All	AC, DCEP or DCEN
E7018	110–165 A	65–100 A	Low	All	AC or DCEP
E7024	140–190 A	—	Low	Flat/horizontal fillet	AC, DCEP or DCEN

Amperage values from the Miller stick setting calculator. Check the product data sheet, since some manufacturers shift the range slightly.

Running a rod outside its rated amperage or polarity range changes the coating chemistry the classification was built around, not just bead quality. Polarity is part of why stick welding still wins in the field.

DCEP vs DCEN: What Actually Changes at the Weld Pool

Shop talk eventually hands you a tidy rule: DCEP digs deep, DCEN stays shallow. It is right often enough to be useful, and wrong often enough to cost you a good weld.

Start with the mainstream practical description, which comes straight from the manufacturers. ESAB credits DCEP with strong penetration and considers it suitable for thicker section joints, while DCEN gives less penetration and more control over the puddle. That is why fabricators reach for DCEP on structural fillets, thick plate root passes, and anywhere they want the arc pushed into the joint.

Now the part most guides skip

Physics argues the other way, and it is not subtle. According to the University of Alberta welding engineering handout, roughly two-thirds of DC arc heat is deposited at the anode and about one-third at the cathode. Under DCEP the consumable electrode is the anode, so the “deep penetration” polarity actually sends most of the arc heat into the rod rather than the plate.

That is exactly why MIG welding of steel runs electrode positive (DC+) for wire melt rate: the arc works as a heat source to melt filler metal quickly. TIG runs electrode negative (DC-) so more heat goes into the workpiece and the tungsten stays cooler and lasts longer. See aerospace TIG welding standards and techniques for the same heat placement story in another process.

So both descriptions are true at once. DCEP is hot at the electrode, so the rod melts faster, lays down faster, and burns through faster. DCEN is hot at the workpiece, so more of the arc’s energy arrives in the plate.

Why the rule breaks down

Final penetration is a sum of variables: where the heat lands, the arc’s “dig” (the plasma jet and electromagnetic pinch driving into the molten pool), amperage, travel speed, and coating chemistry. Change one and the result moves.

Two rods that sit next to each other in AWS A5.1 make the point. The AWS classification puts E6010 on DCEP and E7018 on AC or DCEP, yet charts such as the Baker’s Gas electrode polarity chart rate E6010 as deep penetration and E7018 as low to medium. Same polarity, very different behaviour, because the cellulose coating of a 6010 drives a deep, digging arc while the low-hydrogen coating of a 7018 spreads a quiet, low-penetration puddle.

What you can actually see at the pool

• Electrode melt rate and burn-through. On DCEP the rod melts quickly and can drop through thin material or pinch the puddle. On DCEN it feeds more slowly and lays down deliberately.
• Bead width and convexity. A DCEP bead on the same rod and amperage tends to be narrower and more convex. DCEN usually gives a flatter, wider profile with more reinforcement you can grind down.
• Spatter. Cellulosic rods such as E6010 and E6011 are rated high spatter in manufacturer usage charts. Low-hydrogen E7018 runs a smooth, quiet arc with very low spatter. Coating chemistry is the bigger lever.
• Slag. Slag fluidity and how cleanly it releases shift with polarity. A stubborn, crusty blanket is often a polarity and coating symptom rather than a technique one.
• Puddle control. DCEN gives more time in the puddle, which is why it is easier to push a fillet bead around a pipe or hold a quiet pool overhead. DCEP lays down fast and rewards a steady hand.
• Arc sound. The change in arc pitch between the two polarities is obvious once you hear it, and many welders use it as quick confirmation that the machine actually switched.

Picking the electrode for your joint and position is covered in the all position welding rod guide.

Run your own A/B test

This is the fastest way to internalise the difference, and it takes an afternoon of scrap plate.

1. Fix the variables. Same rod, same amperage, same joint, same travel speed, same stick-out, same position. Only polarity changes.
2. Make bead A on DCEP and bead B on DCEN back to back on the same coupon, and let them cool.
3. Compare them side by side: bead width and convexity, spatter around the toes, how the slag peels (one piece or three passes with a chipping hammer), how fast the rod consumed, and the arc sound.
4. Measure penetration properly. Make a single V-groove or square-groove butt joint in 3/8 to 1/2 inch plate, fill it, then cut the coupon in half across the weld. Grind the cut face flat and measure from the original plate surface down to the deepest point of fusion, using a printed scale or calipers to compare the two halves.

Polarity sets the conditions; everything else you do at the torch sets the result. Pick the polarity the electrode specifies, then manage penetration with heat input, travel speed, and arc length.

AC vs DC: Where Alternating Current Still Wins

So far the choice has been between two DC polarities, but there is a third option worth a fair hearing. On an AC machine the current reverses direction every half cycle, so at 60 Hz the arc flips between electrode positive and electrode negative roughly 120 times a second. It samples DCEP for a moment, then DCEN, then DCEP again.

Penetration on AC therefore lands between the deep penetration of DCEP and the shallower profile of DCEN. It is a compromise, and compromises usually lose to a well matched DC setup. But a compromise is what you want in two specific situations.

The cleaning action AC gives you for free

The first advantage is scrubbing action on the workpiece. As polarity reverses, the root of the arc moves around and mechanically breaks down oxide films, scale, rust and paint residue that would otherwise stop the puddle from wetting out. ESAB notes that AC is more forgiving on contaminated surfaces because of this cleaning action.

That trait is why AC never really died out. A farmer fixing a trailer bracket in the rain or a tech welding a rusted handrail: these are AC jobs, because grinding to bright metal can take longer than the weld. AC also keeps showing up in the reasons SMAW wins on farms, fields and one-off repairs. The trade-off is real: AC runs hotter and less predictably, spatters more on cellulosic rods, and lays a wider, flatter bead than a DC arc.

Arc blow: the problem DC can cause and AC mostly cannot

The second advantage is arc blow, the tendency of a DC arc to wander sideways off the joint. A DC current creates a magnetic field with a fixed direction that deflects the arc. ESAB ties arc blow strongly to DC for exactly this reason, which makes AC the sensible answer wherever arc blow is likely.

AC largely solves it. As the current reverses it induces eddy currents in the base metal, and the magnetic fields they set up greatly weaken the fields pushing the arc around. That is the mechanism Lincoln Electric describes, and it is why a 40 amp AC arc can hold a puddle on a rusty track shoe that a 120 amp DC arc will not.

Two calibration points from the same source: serious arc blow problems usually do not occur in stick welding with DC up to approximately 250 amps, and 9% nickel steels have such high magnetic permeability that fields above 20 Gauss are usually enough to cause problems. Arc blow is not a universal DC flaw. At normal shop amperages on ordinary mild steel, DC rarely misbehaves this way. On long heavy joints, ground pieces, magnetized stock or any nickel alloy it is a real risk, and AC is cheap insurance.

Modern inverter AC is not your grandfather’s transformer

Old line-frequency AC welders were crude: the arc extinguishes each time the current passes through zero, and restriking was a matter of luck. That is why potassium is in the E6011 coating: as University of Alberta welding material explains, potassium lowers the ionization energy and stabilises the arc so it survives on simple 50 or 60 Hz AC machines little more than a transformer.

Today’s inverter AC is a different animal. Higher-frequency switching and better arc control produce a cleaner, more stable arc than any old transformer, which is why low-hydrogen potassium electrodes such as E7016 and E7018 are routinely specified for AC. The AWS A5.1 classification system lists both as AC or DCEP capable.

One hard limit is worth remembering: E6010 is DCEP only and cannot be run on alternating current. If your procedure calls for E6010, AC is not an option, no matter how dirty the joint.

Factor	AC	DCEP (DC electrode positive)	DCEN (DC electrode negative)
Arc behaviour	Reverses every half cycle	Steady, focused arc	Steady, softer, wider arc
Penetration	Average of both DC cases	Usually deepest	Usually shallowest
Cleaning action	Yes, on dirty steel	None	None
Arc blow risk	Markedly reduced	Present on magnetic steel	Same causes
Common electrodes	E6011, E6013, E7014, E7016, E7018, E7024	E6010, E6011, E6013, E7018	E6012, E6013, E7027
Typical use	Field and site repair on dirty steel	Structural and shop fabrication	DCEN-rated or control-critical rods

How to decide

Choose AC when the surface is contaminated and cleaning it is impractical, when arc blow keeps recurring on a joint, or when the procedure calls for it. Choose DC for everything else, where you get a more controllable arc, less spatter and easier puddle control. If you are unsure, the qualified welding procedure specification outranks any general rule.

How to Switch Polarity on Your Own Stick Welder

Polarity sounds like the easiest adjustment in the shop, and it is also where plenty of people get burned, because it happens with a live machine, a loose connector, and a distracted operator. Here is the short version: on a stick inverter, changing polarity means swapping the electrode and work leads between terminals with the machine switched off. On multiprocess machines you often have a front panel setting instead, and on old AC transformers there is nothing to switch at all.

Step 1: Know What Kind of Machine You Have

Before touching a terminal, identify your power source. The common types behave differently, and mixing them up is where most lead-swapping mistakes begin.

Machine type	How polarity changes
Modern inverter / multiprocess welder	Usually a stick polarity setting on the front panel or setup menu. Some also accept a lead swap.
Inverter-only stick machine	The lead swap between terminals is the polarity change.
Older DC generator welder	A reversing or polarity switch on the unit, or the same lead swap.
AC transformer	No polarity selection exists. The arc alternates by design.

Multiprocess machines need special care. Many label terminals 2T and 4T, and those labels describe MIG wire polarity, not stick electrode polarity. The mapping is not always one-to-one, so the manual is the only reliable guide. If your machine lets you pick a stick setting such as DCEN, DCEP or AC separately, that setting will usually override whatever the leads are doing. Check the manual for the exact stick polarity options before assuming the terminals tell the whole story.

Step 2: Do the Lead Swap, Machine Off

For the common case, an inverter-only stick welder, the procedure is straightforward:

1. Turn the machine off and unplug it, or at minimum switch it off and let it sit a minute.
2. Disconnect the electrode holder lead and the work clamp lead from the machine terminals.
3. Move the electrode holder lead to the terminal matching the polarity you want. This is the lead that changes sides for stick polarity.
4. Reconnect the work clamp lead to the other terminal.

For DCEP (reverse polarity), the electrode holder goes to the positive (+) terminal and the work clamp stays on the negative (−) terminal. For DCEN (straight polarity), it is the opposite: electrode holder to negative, work clamp to positive.

Both ESAB and Lincoln Electric agree on one point: the electrode package specifies the correct polarity, and the rod only welds successfully when that recommendation is followed. If your machine and your electrode disagree, the manual and the rod box win.

Step 3: Route the Cables Like You Mean It

Polarity is only half the electrical path. How you route the leads decides how stable the arc feels, and this is where beginners quietly create arc blow problems.

• Keep both leads short. Long loops act like extra turns of a transformer.
• Do not coil excess cable. Coiling or poorly routing welding cables creates localized magnetic fields right next to the joint, which worsens arc blow.
• Do not run the work lead through or alongside the weld seam. The return current should take the shortest, cleanest path back to the machine.
• Make sure the clamp jaw bites clean metal. High resistance in the ground connection can destabilize the arc on its own, independent of magnetism in the workpiece.

Lincoln Electric’s guide to preventing arc blow covers the magnetic field side in more detail if your arc starts wandering after a swap.

Step 4: Verify Before You Weld For Real

Never trust the switch. Run a short test bead on scrap with the same rod you plan to use and check four things:

1. Arc sound. DCEP on a cellulosic rod is noticeably crackly and loud. That is normal, not a fault.
2. Arc stability. A stable arc sits in one spot and spreads smoothly.
3. Slag behavior. Slag should detach and float off rather than balling up on the bead.
4. Stick-out. The rod should burn off evenly, not mushroom and stall.

Finally, confirm the machine’s polarity indicator, or re-read the manual, and match it against what you physically did with the leads. If they disagree, you found the problem before it found your weldment.

With the machine set and verified, pick the right rod confidently. Our all position welding rod guide shows which electrodes work in which positions, and the polarity section earlier in this article covers decoding the classification numbers.

Troubleshooting: Symptoms, Causes and the Polarity Fix

Polarity is one variable in a long chain. Most shop arguments about polarity start when someone blames the switch and stops looking. The table lines up symptoms with likely causes, marking which are polarity-related. Check every row before reaching for the leads.

Symptom	Polarity-related cause	Other likely causes
Arc wanders or blows sideways	Rarely; DCEN and DCEP differ in arc character	Arc blow, clamp position, magnetized metal, excess amperage, air drafts
Poor or intermittent fusion	DCEN on a DCEP rod, or where the procedure demands DCEP	Dirty joint, wrong amperage, fast travel, wrong diameter, cold clamp
Excessive spatter	Wrong polarity for a cellulosic rod (E6010 on DCEP spatters by design)	Long arc, excess amperage, rust or paint, poor ground connection
Slag will not release	Rarely. E7018 makes heavy slag; some rods run less fluid	Moist electrode, wrong amperage, frozen slag, iron-rich base metal
Electrode stubs out early	DCEN when the rod calls for DCEP, giving a weak, erratic arc	Low amperage for the diameter, short arc, wrong diameter
Burn-through, rod melts too fast, or a very hot, wide, flat puddle	DCEP on a DCEN rod, or where DCEN was needed for puddle control	Excess amperage, slow travel, thin metal, excessive weave, long arc
Undercut	Usually an arc too hot or too long for the joint	Fast travel, wrong work angle, long arc, excess amperage, dirty edge
Crater cracking	Wrong polarity can contribute via an unstable arc and poor pool solidification	No crater fill, traveling out of the puddle, dirty metal, high sulfur base metal
Arc will not strike at all	Leads reversed beyond the machine’s tolerance, or an unsupported machine mode	Set to TIG or MIG, foot control fault, dead ground clamp, gas path issue, bad lead connection, wet electrode

When Polarity Is Genuinely the Fix

Three situations where flipping the switch fixes it outright.

1. Wrong polarity for the rod. If the box says DC+ and you are on DCEN, that is the answer. A DCEN arc on E7018 is cold and erratic and the electrode stubs out. DCEP on a DCEN rod pushes heat into the rod, giving a fat, fast bead and more spatter.
2. DCEN where the procedure calls for DCEP. On code work the qualified procedure dictates polarity, and the opposite is a deviation that can void the qualification. If an inspector flags it, fix the machine.
3. DCEP where DCEN is needed for control. On thin sheet, stainless, or a hot, fast puddle you struggle to control, DCEN gives a softer, wider, more forgiving arc. That is legitimate even though DCEP is the default for most rods.

When Polarity Is Not the Fix

Arc blow is the classic trap. According to ESAB, it is strongly associated with DC welding because the magnetic field from DC current has a fixed direction, while AC reverses each half-cycle and reduces net deflection. If your arc blows sideways, switching polarity will not save you. Fix the geometry.

ESAB also notes that arc blow worsens when the return is far from the weld, when current funnels through the weld end, or when cable routing and coiling creates localized fields. Lincoln Electric points out that high currents make it worse, because field intensity is proportional to the square of the welding current: double the amperage, quadruple the pull.

Arc Blow Fix List

• Move the return clamp closer to the weld.
• Reposition it for symmetrical flow.
• Relocate the return along long seams.
• Use two return points where the joint allows.
• Weld toward the clamp where practical.
• Use back-step or skip welding to spread heat.
• Add run-on and run-off tabs at the seam ends.
• Use AC for the root pass, then DC for fill and cap, only where the qualified procedure allows it; ESAB calls this a common strategy in difficult root conditions, never improvised on code work.

Other things blamed on polarity: an electrode in a damp shed (E7018 needs moisture-free storage and oven baking to keep hydrogen low), rust, oil and paint, excess amperage, wrong electrode diameter, arc drafts, and a ground clamp biting dirty steel instead of clean metal. Clean the joint and clamp before you change the switch.

Crater Cracking Specifically

A crater is where a weld ends and the last thing to solidify, so it is the first place to look for a crack at the end of a bead. Three habits prevent most of it:

• Use the machine’s crater-fill function if it has one
  

  Troubleshooting: Symptoms, Causes and the Polarity Fix

  Polarity is one variable in a long chain. Most shop arguments about polarity start when someone blames the switch and stops looking. The table lines up symptoms with likely causes, marking which are polarity-related. Check every row before reaching for the leads.

  Symptom	Polarity-related cause	Other likely causes
  Arc wanders or blows sideways	Rarely; DCEN and DCEP differ in arc character	Arc blow, clamp position, magnetized metal, excess amperage, air drafts
  Poor or intermittent fusion	DCEN on a DCEP rod, or where the procedure demands DCEP	Dirty joint, wrong amperage, fast travel, wrong diameter, cold clamp
  Excessive spatter	Wrong polarity for a cellulosic rod (E6010 on DCEP spatters by design)	Long arc, excess amperage, rust or paint, poor ground connection
  Slag will not release	Rarely. E7018 makes heavy slag; some rods run less fluid	Moist electrode, wrong amperage, frozen slag, iron-rich base metal
  Electrode stubs out early	DCEN when the rod calls for DCEP, giving a weak, erratic arc	Low amperage for the diameter, short arc, wrong diameter
  Burn-through, rod melts too fast, or a very hot, wide, flat puddle	DCEP on a DCEN rod, or where DCEN was needed for puddle control	Excess amperage, slow travel, thin metal, excessive weave, long arc
  Undercut	Usually an arc too hot or too long for the joint	Fast travel, wrong work angle, long arc, excess amperage, dirty edge
  Crater cracking	Wrong polarity can contribute via an unstable arc and poor pool solidification	No crater fill, traveling out of the puddle, dirty metal, high sulfur base metal
  Arc will not strike at all	Leads reversed beyond the machine’s tolerance, or an unsupported machine mode	Set to TIG or MIG, foot control fault, dead ground clamp, gas path issue, bad lead connection, wet electrode

  When Polarity Is Genuinely the Fix

  Three situations where flipping the switch fixes it outright.

  1. Wrong polarity for the rod. If the box says DC+ and you are on DCEN, that is the answer. A DCEN arc on E7018 is cold and erratic and the electrode stubs out. DCEP on a DCEN rod pushes heat into the rod, giving a fat, fast bead and more spatter.
  2. DCEN where the procedure calls for DCEP. On code work the qualified procedure dictates polarity, and the opposite is a deviation that can void the qualification. If an inspector flags it, fix the machine.
  3. DCEP where DCEN is needed for control. On thin sheet, stainless, or a hot, fast puddle you struggle to control, DCEN gives a softer, wider, more forgiving arc. That is legitimate even though DCEP is the default for most rods.

  Quick Note: E6013 has a quiet arc, moderate penetration and easy-to-clean slag, while E7018 makes a heavy slag that sticks to the metal. Complaining about stubborn slag? Check the rod first.

  When Polarity Is Not the Fix

  Arc blow is the classic trap. According to ESAB, it is strongly associated with DC welding because the magnetic field from DC current has a fixed direction, while AC reverses each half-cycle and reduces net deflection. If your arc blows sideways, switching polarity will not save you. Fix the geometry.

  ESAB also notes that arc blow worsens when the return is far from the weld, when current funnels through the weld end, or when cable routing and coiling creates localized fields. Lincoln Electric points out that high currents make it worse, because field intensity is proportional to the square of the welding current: double the amperage, quadruple the pull.

  Arc Blow Fix List

  • Move the return clamp closer to the weld.
  • Reposition it for symmetrical flow.
  • Relocate the return along long seams.
  • Use two return points where the joint allows.
  • Weld toward the clamp where practical.
  • Use back-step or skip welding to spread heat.
  • Add run-on and run-off tabs at the seam ends.
  • Use AC for the root pass, then DC for fill and cap, only where the qualified procedure allows it; ESAB calls this a common strategy in difficult root conditions, never improvised on code work.

  Other things blamed on polarity: an electrode in a damp shed (E7018 needs moisture-free storage and oven baking to keep hydrogen low), rust, oil and paint, excess amperage, wrong electrode diameter, arc drafts, and a ground clamp biting dirty steel instead of clean metal. Clean the joint and clamp before you change the switch.

  Crater Cracking Specifically

  A crater is where a weld ends and the last thing to solidify, so it is the first place to look for a crack at the end of a bead. Three habits prevent most of it:

  • Use the machine’s crater-fill function if it has one. It ramps current down so the pool tapers instead of freezing around a keyhole.
  • Hold the electrode slightly upward into the pool and let the arc fill the crater before you break it.
  • Keep the correct polarity so the pool solidifies cleanly.

  Short Note: Before blaming polarity, run a sanity check: read the rod box, confirm the stick polarity setting matches the leads, and make a test bead on clean scrap. If it looks right, the problem is elsewhere in the setup.

  Between aluminum and steel work, or between processes, the electrode holder and work leads are often left swapped. Our guides on aluminum flux core welding and aluminum MIG welding cover polarity and gas setups, and our all-position welding rod guide helps you pick the right rod before fault-finding. The fastest cure for a bad bead is a clean joint, the right rod, the right amperage and polarity set to match the box.

  The Working Setup: Polarity, Consumables and a Safe Shop

  Polarity isn’t just a switch on the machine, it’s a decision that affects weld quality, consumable life, and shop safety. Get it right for the job at hand, and the rest of the setup will fall into place far easier.

  Polarity and Procedure Compliance

  For hobby work, changing polarity can be a matter of preference. For code work, it’s mandatory. Any qualified welding procedure specification will dictate the exact polarity for a weld, along with the electrode, amperage range, joint design, and preheat. As ESAB’s polarity basics point out, an electrode’s classification is built around a matched coating chemistry and polarity, so straying from either can break that pairing.

  Switching an E7018 from DCEP to DCEN, for example, will change how its low-hydrogen coating decomposes and how the rod melts. The same goes for running any rod outside of its approved amperage range. These changes alter bead profile, slag behavior, and most importantly, the mechanical properties of the weld. For higher specification jobs, it’s worth knowing how alloy steel welding electrodes are classified, as the same matching principle applies to them.

  Quick Note: A WPS is a legal document in a code shop. If the machine polarity doesn’t match the WPS, the weld is out of procedure regardless of how clean it looks. Always check it before striking an arc.

  Consumable Care and Storage

  The biggest concern for many consumables isn’t the arc, it’s moisture. Low-hydrogen electrodes are hygroscopic, meaning they will absorb water from the air if left unsealed. That moisture is introduced into the weld pool as hydrogen, which can lead to hydrogen-assisted cracking in restrained, hardenable steels, as well as porosity.

  • Keep sealed: Only open electrode cartons when ready for use, and avoid leaving loose rods exposed on an open bench.
  • Bake by the data sheet: Follow the manufacturer’s recommended holding temperature and time for reconditioning. Many also limit how many times an electrode can be re-baked before the coating itself is damaged.
  • Respect the use window: Once baked, low-hydrogen rods are only viable for a set amount of time before they need to return to the oven or be scrapped.
  • Maintain your oven: Keep it away from spatter and moisture, and log what goes in and when to avoid guesswork.

  Not every rod requires this level of care. Cellulosic electrodes like the E6010 are far less sensitive to moisture, which is a large part of why they’re still relied on for field root passes on pipe.

  Fume, Ventilation and Fire Safety

  Welding fume is a legitimate health hazard, not a nuisance to wave away. According to OSHA’s welding fact sheet, overexposure can cause eye, nose, and throat irritation, dizziness, nausea, lung damage, and cancers of the lung, larynx, and urinary tract. Manganese fume in particular can cause Parkinson’s-like symptoms, so grinding and cutting need extraction just as much as welding does.

  The greatest concern for carbon and stainless steel is hexavalent chromium. NIOSH treats all hexavalent chromium compounds as occupational carcinogens, with welders being a high risk group. To combat this, OSHA 1910.1026 sets a permissible exposure limit of 5 micrograms per cubic metre as an 8-hour time-weighted average, with an action level of 2.5 micrograms per cubic metre. Under 29 CFR 1910 Subpart Q, mechanical ventilation of at least 2,000 cubic feet (57 cubic metres) per minute per welder is required in certain enclosed workspaces.

  Fire prevention is just as non-negotiable. OSHA 1910.252 requires clear work areas free of combustibles, removal of flammable materials from the vicinity, protection from falling sparks, hot work permits where needed, fire blankets, and a designated fire watch.

  Note: Galvanised, painted, solvent-contaminated, or oily surfaces are some of the most hazardous to weld. Strip them before striking an arc, and never weld over solvent residue. For aluminium specifically, prep is just as critical, so it’s worth following a proven method for cleaning aluminium the right way.

  Matching Setup to the Job

  Take a hydraulic ram cylinder rebuild on a farm. With rust, old paint, and grease to contend with, AC with a cellulosic rod is often the pragmatic choice. Its cleaning action helps penetrate contamination, and cosmetic perfection isn’t the goal here. Contrast that with a shop fabricating a degreased, bevelled mild steel bracket: DC electrode positive with an E7018 is the move, giving a stable arc and the mechanical properties demanded by its procedure.

  These two jobs prove the same point: polarity is a tool, not a dogma. Read the rod box and the procedure first. From there, consult a reliable all position welding rod guide to match consumables, and it’s no surprise as to why stick welding still wins for so many of these rough, out of shop repairs.

  Putting It Together: A Polarity Decision You Can Trust

  If you remember one thing from this guide, make it this: for the vast majority of stick welding you will do in a modern shop, set the machine to DC electrode positive (DCEP), also sold as reverse polarity. That is the polarity E6013, E7018 and most other coated electrodes are built, classified and qualified for. Everything else is an exception, and the exceptions are few enough to learn in five minutes.

  Before you touch the polarity switch, read the rod box. The classification printed on it is not decoration. The last digit tells you the polarity the electrode is approved for, and Lincoln Electric’s AWS classification reference is the cleanest decoder you can keep on your phone. Treat the manufacturer’s data sheet as the source of truth over anything you read online, including this article.

  Your 30-second decision path

  1. Read the box first. Find the classification and the polarity statement. No guesswork required.
  2. Is it DCEP only? E6010 and E7015 fall here. Set DCEP on a DC machine. There is no second option, and there is no AC substitute.
  3. Is it DCEN only? E7027 is the common one. Set DCEN. Again, non-negotiable, so polarity becomes a decision rather than a preference.
  4. Does it say AC or DC in either polarity? E6013, E6014 and E7024 land here, and these are the electrodes most often run both ways. They make the easiest general-purpose rod collection for a new welder. Default to DCEP, and drop to DCEN only when you want a softer, wider, more controllable arc on thin or delicate work.
  5. Is the surface dirty or the base metal magnetically susceptible? Consider AC, most often for the root pass, and only where your qualified procedure allows it.

  Quick-reference card

  Electrode	Coating	Usable polarity	Best use
  E6010	High cellulose sodium	DC+ (DCEP) only	Root passes on pipe
  E6011	High cellulose potassium	AC or DC+	Field repair, oil and gas
  E6012	High titania sodium	AC or DC−	General, often sold as DCEN
  E6013	High titania potassium	AC or DC, either	General purpose and training
  E7014	Iron powder titania	AC or DC, either	Fast fillet welds
  E7015	Low hydrogen sodium	DC+ only	Low hydrogen, code work
  E7016	Low hydrogen potassium	AC or DC+	Low hydrogen, code work
  E7018	Low hydrogen potassium / iron powder	AC or DC+	The structural workhorse
  E7024	Iron powder titania	AC or DC, either	Fastest deposition, horizontal fillet only
  E7027	High iron powder	DC− (DCEN) only	High deposition, flat and horizontal

  Two columns you may find on a data sheet are worth understanding. The usable-polarity column tells you what the machine may be set to; the rod’s qualification tells you what it was actually approved at. When the two differ, the qualification wins. A rod sold as “AC or DC+” is qualified on either, but a rod listed as DC+ only was likely never tested under AC, so running it on AC is a risk, not a shortcut.

  Electrode	1/8 in (3.2 mm)	3/32 in (2.4 mm)
  E6010	20–80 A	20–90 A
  E6013	20–80 A	40–100 A
  E7018	30–80 A	40–100 A
  E7024	40–120 A	50–145 A

  These figures come from the Miller stick welding calculator. Treat every number as approximate and test your welds to confirm they meet your specifications. Miller’s own polarity guidance is worth keeping in mind as you set up: DCEP gives the most weld penetration, AC gives medium penetration with potentially more spatter, and DCEN gives the least.

  Quick Note: The two rods that make polarity a real decision are E6010 (DCEP only) and E7027 (DCEN only). Every other common electrode gives you room to adjust. If your electrode is flexible, use that flexibility for control, not for guesswork.

  Five things to remember

  1. DCEP on the electrode holder lead is your default for modern stick work.
  2. The rod box is the source of truth. Read it every single time you change electrodes.
  3. DCEP makes the rod the hot side; DCEN puts more heat into the plate. That one fact explains most of what you will observe at the pool.
  4. “Electrode positive” and “reverse polarity” are the same thing, and so are “electrode negative” and “straight polarity.” Learn both names or one of them will fool you.
  5. AC is the specialist, not the default. Reach for it on dirty surfaces and magnetically susceptible base metal, and follow the qualified procedure.

  Here is the honest hierarchy, and it matters more than any single switch. Polarity is a real control, but joint preparation, amperage inside the electrode’s approved range, electrode condition and arc length account for the large majority of weld defects. When a weld goes wrong, walk the whole setup before blaming the polarity switch: clean the joint, confirm the amperage, check for damp rods, shorten the arc, then look at polarity.

  If you want a broader look at the process itself, our breakdown of why SMAW still wins is a good companion read, and the all-position rod guide helps when you are choosing which electrodes to buy next.

  Note: OSHA requires that the potentially hazardous materials in fluxes, coatings and filler metals be covered by your employer’s Hazard Communication program under 29 CFR 1910.1200. Keep the rod data sheets in your binder. They tell you the approved polarity, the amperage range and the baking temperature, and they are what an inspector will ask for.

  From here, the natural next steps are our stick welding fundamentals tutorial, the electrode buying guide for choosing rods that match your work, and the inverter welder reviews if you are still deciding which machine to put behind your bench. Bring a box of rods to the bench, set DCEP, and run a test bead on scrap before you touch a customer part. That habit will do more for your welds than any theory in this guide.

  Frequently Asked Questions

  What polarity should I use for stick welding?

  For most modern stick welding, use DC electrode positive (DCEP, also called reverse polarity): the electrode holder goes on the positive terminal and the work clamp on the negative. That is the specified polarity for the common E6013, E6018 and E7018 electrodes. Always check the label on the rod box first, since a few electrodes, such as E6010 and E7027, are restricted to one polarity.

  Which polarity gives deeper penetration in stick welding?

  Most manufacturers and training materials credit DCEP with a hotter, more focused arc and better penetration on thicker joints, while DCEN gives a shallower, more controllable pool. Arc physics also shows that roughly two-thirds of DC arc heat lands at the anode, so under DCEP the rod itself melts faster. Penetration in stick welding is therefore a combination of polarity, amperage, travel speed, arc length and electrode coating chemistry, not polarity alone.

  Can I run E7018 electrodes on AC?

  Yes. AWS A5.1 classifies E7018 as usable on AC or DCEP, and its potassium-based coating was designed in part to produce a stable arc on AC power sources. Most modern inverter welders make AC easy to dial in. E6010 is the opposite case: it is a DCEP-only electrode and will not run on AC.

  What does reverse polarity mean in stick welding?

  Reverse polarity is another name for DCEP, or DC electrode positive. The electrode holder lead is connected to the positive terminal of the machine and the work clamp to the negative. Straight polarity is the equivalent term for DCEN, where the electrode holder is on the negative terminal and the work clamp on the positive.

  How do I change polarity on my stick welder?

  On most inverter welders, turn the machine off, move the electrode holder lead to the terminal matching the polarity you want, and leave the work clamp on the other terminal. Older DC generator machines have a reversing or polarity switch, and AC transformers have no polarity setting at all. Multi-process machines often have a dedicated stick polarity menu option, so read the manual rather than assuming the MIG 2T/4T labels apply to stick.

  Why does my arc wander and will changing polarity fix it?

  Arc wander is most often caused by magnetic arc blow, which is tied to DC current and to where your ground clamp is attached, not to the polarity setting itself. Move the return clamp closer to the joint, weld toward the clamp, use two returns on long seams, and use AC for the root pass where the qualified procedure allows. Also rule out air drafts, a dirty ground clamp and a magnetically susceptible base metal.

  Is DCEN the same as straight polarity?

  Yes, they are two names for the same thing: the electrode holder on the negative terminal, the work clamp on the positive. DCEN is the modern, unambiguous label, and it is also used by welders to describe GTAW and most MIG-on-aluminium setups, which run electrode negative.

  My E7018 slag is thick and hard to remove. Is that a polarity problem?

  Usually not. E7018 has a low-hydrogen iron powder coating that produces heavy, sticky slag by design, which is the trade-off for its quiet, low-spatter arc and excellent mechanical properties. E6013 is the rod with the famously easy-to-chip slag. Make sure your amperage is within the range for your rod diameter and that you are letting the slag cool before chipping it, but do not expect a polarity change to turn E7018 into an E6013.

  Does the same polarity rule apply to MIG and TIG?

  The underlying principle is the same but the answer is inverted. MIG welding of steel runs electrode positive (DC+) for wire melt rate, while TIG runs electrode negative (DC-) so that more heat goes into the workpiece and the tungsten stays cooler. In stick welding, DCEP on the electrode holder is the default because that is how the coated electrodes are specified.