Stick welding polarity: DCEP, DCEN and AC
On a DC machine the two cables are not the same. Putting the electrode holder on positive or on negative changes where the heat goes. With the wrong polarity the rod misbehaves, the arc turns unstable and the bead comes out full of spatter.
DCEP (electrode positive, also called reverse polarity): electrode holder on the positive terminal, work lead on the negative. It is the most used for stick, including the 7018. DCEN (electrode negative, straight polarity): electrode holder on negative, used by a few rods such as some 6013 and 7024 types; it penetrates less. AC alternates between the two. Always confirm on the rod package.
DCEN, DCEP and AC: what changes
- DCEN (straight polarity): electrode negative, work positive. The rod melts off faster and penetration is shallower.
- DCEP (reverse polarity): electrode positive. Deeper penetration, which is why most stick rods and MIG on steel use it.
- AC (alternating current): reverses polarity every cycle and balances the two characteristics.
In practice, “DCEP” means the electrode holder cable goes on the positive (+) terminal and the work clamp on the negative (−). “DCEN” is the opposite. On a stick inverter, changing polarity is just swapping the two cables between terminals, with the machine switched off. On an AC-only transformer machine you do not choose the polarity.
Polarity of each stick electrode
| Electrode | Coating | Current | Main use |
|---|---|---|---|
| E6010 | Cellulosic | DCEP | Root pass on pipe |
| E6011 | Cellulosic | DCEP or AC | Pipe root (AC version) |
| E6013 | Rutile | DC or AC | Beginners, thin plate, light structures |
| E7018 | Low-hydrogen | DCEP or AC | Critical structures, industrial pipe |
| E7024 | Rutile, iron powder | DC or AC | High productivity in flat position |
Table 3.1 of the e-book The Welder's Forge.
The 7018, a low-hydrogen rod, runs on DCEP on an inverter. The 6013 is tolerant, takes DC or AC, which is why beginners like it. The differences between the two are in 6013 vs 7018.
The complete e-book
Reference tables, stick, MIG/MAG and TIG technique and safety in one PDF, written in plain American English.
What about flux-cored wire and TIG?
MIG with solid wire and shielding gas runs on DCEP. With flux-cored wire the polarity depends on the wire, and that is where many people slip when they change spools:
| Wire | External gas | Polarity |
|---|---|---|
| E71T-1C | CO2 | DCEP |
| E71T-1M | 75% Ar / 25% CO2 | DCEP |
| E71T-8 | None (self-shielded) | DCEN |
| E70T-4 | None (self-shielded) | DCEP |
Table 6.1 of the e-book The Welder's Forge. Always confirm on the wire package.
Two self-shielded wires, two different polarities: read the label. If your machine runs gasless wire, see gasless MIG (flux-core). In TIG the usual setting for steel and stainless is DCEN and aluminum calls for AC; the tungsten changes with it, as explained in tungsten electrode colors.
Signs of reversed polarity
- Lots of spatter and an arc that spits.
- Unstable arc, hard to hold.
- Poorly formed bead, with weak fusion.
When a new rod or wire misbehaves, check the polarity on the package before touching the current. Swapping two cables fixes in seconds what no setting will.
Quick checklist before you strike the arc
- Read the rod package: it says DCEP, DCEN or AC.
- Look at the machine terminals: is the electrode holder cable on the right sign? Is the work clamp on the other one?
- Check the connectors: fully seated and tight, no cable with cracked insulation.
- Clamp the work lead close to the joint, on clean metal.
- Run a test bead on scrap. Soft arc and a steady crackle: go ahead. Lots of spatter and a spitting arc: stop and review the connection.
If you switch rods in the middle of a job (from 6013 to 7018, for example), repeat the checklist: it is easy to forget that the new package calls for a different hookup.
Unplug the machine before moving cables between terminals and tighten the connectors well: a loose connection heats up and can burn the terminal. Work on the building's wiring belongs to a licensed electrician, and the NEC and the machine manual set the rules.
Frequently asked questions
What do DCEP and DCEN mean in welding?
What polarity is a 7018 rod?
What polarity is a 6013 rod?
What polarity does gasless flux-cored wire use?
Want all of this in one PDF?
The e-book The Welder's Forge covers stick, MIG/MAG and TIG from the first arc to the shop floor, with reference tables and technical figures, in plain American English.
PDF for phone, tablet or computer · instant access · 14-day guarantee