Hi guys,
Been a while since I’ve been here so thought I’d drop in and say Hi as well as seek some electrical expertise.
I’m running a line for my 240v welder in my shop and had a quick question. My welder from the mid 1980s has only a three lead plug (hot, hot, ground-neutral combined). I’m thinking this now violates the NEC requuirements by having a shared groundneutral?
What should I do?
Here is the “rest of the story”. Its fed off a 100amp subpanel to my shop and then a 50amp breaker specifically for the welder. Should I run just the three leads and if so, where do I connect the groundneutral in the panel? To the ground or to the neutral bus? These are separated of course since it is a subpanel.
Or do I have to rewire my welder and if so what do I do just ground the frame and make the lead which is now ground-neutral just neutral?
Thanks in advance for what is probably an easy soultion for an electrician but a baffling one for me. I want to follow the code of course but more importantly don’t want to get hurt down the road using the welder.
Mike R.
Replies
Hmmm. I suspect that your welder is a straight 240v device without any 120v components.
Many ranges and driers have 120v timers and controls that means they have to have a neutral. This neutral was allowed for many years to piggyback on the ground. Within the last decade or so this combined neutral/ground was seen, rightly so, as a safety hazard. For these units a four wire cord and feed is the norm.
If you welder has no 120v components a three wire cord and feed, properly sized of course, should be fine as there is no need for a neutral. You might look on the plate on the back of the machine and see if it says 240v or 120/240v.
If there is need for a neutral, there are 120v components, you might be better off leaving it as is as long as the cord and internal wiring are still good. There a literally thousands of ranges that still have three wire cords and feeds. These are grandfathered in and are, generally, not required to be changed.
In such a case the only thing I would do would be to inspect the neutral connections to make sure that they are sound. The failure of the neutral could cause the enclosure to become charged at 120v and present a shock hazard.
4,
Thanks for the reply. Nope, no 120v components. The cordwiring of the welder is in great shape as its seldom used.
So it sounds like I can just stick with the three wire setup and run the third wire directly to the ground bus with no need for the neutral. Thanks
Mike
Any time. Glad I could help.