AC, DCEN and DCEP. When to use them. When not to use them. Part 1

If you are confused by welding terminology like “Reverse Polarity” and “Straight Polarity”, this blog  will be a basic primer to help you understand the basics of polarity and where and how to use them.  Every welding process has a preferred polarity.   This means that the lead or cable connected to the gun, torch or electrode holder is connected to the receptacle with the stated polarity.   Usually this will be stated as a + sign or a – sign.

Sometimes it will simply be stated as work and torch, with or without a polarity designation to reduce the chance of confusion.

Regardless, the unit will still have polarity.  Units that produce AC may not have anything but a work and torch designation.  Even though technically there is no polarity, proper AC connection is important as it can lead to overheating of either the work clamp or the electrode side due to the way the unit is designed.  So be sure to always check that connection is properly observed.   DCEN is also called Straight Polarity.   Straight Polarity is only commonly used in a few processes.  The first is TIG.   The TIG torch should always be connected to the side marked with the negative sign, even if you are welding in AC.   Particularly with new welders that have adjustable cleaning functions, a reversed lead can cause significant arc instability and overheating of the torch and or the unit.  The second place you’d use DCEN is with plasma cutting.

Plasma cuttings is a electrode negative cutting process only.  For multi-units with plasma as a functional component of the welder, never attempt to cut with the torch in the positive or damage to the torch will occur.  At the very least it will destroy a set of consumables in seconds when the flow of electricity is reversed from what it should be.