50 or 30 amp RV plug vs welder plug

Okrivia · Post by **Okrivia** » Tue Oct 01, 2019 8:12 am

I'm not an electrician or electrical engineer.

I understand that a 240volt welder plug has only three prongs (I believe two hots and a common). Am I correct so far? If so, what about the ground? Does a welder not have a ground wire?

An 50 amp RV plug will have four prongs: a pair hots, a common, and a ground.

Lets say an enclosed utility trailer has a freezer, a couple of refrigerators, and a few outlets for food prep machinery. The trailer is used for cooking and preparing food. The trailer has a 30amp RV plug plugged into an onboard generator. The trailer owner has used an adapter to plug the trailer into a 50amp RV outlet.

I've been told ... NEVER, NEVER, EVER plug an RV into a welder outlet (using a homemade adapter) because the welder outlet has no grounding protection and this could/will cause serious problems for the equipment and devices plugged into.

I would like to be schooled on what the deal is with this. I believe the warnings are probably correct, but I don't completely understand the issued because the warnings. Is the risk there, but very unlikely to occur? Or is the risk very likely to occur?

Post by **Razorback** » Tue Oct 01, 2019 11:54 pm

The biggest issue is that a welder is 240V, RVs operate on 110V. A 30A or 50A RV service is 110v.

Post by **Razorback** » Tue Oct 01, 2019 11:56 pm

Razorback wrote: ↑Tue Oct 01, 2019 11:54 pm The biggest issue is that a welder is 240V, RVs operate on 110V. A 30A or 50A RV service is 110v.

It would be like plugging in your vacuum sweeper into your dryer connection at the house if you could rig up a connector to do it.

Follow the advice of NEVER plugging your RV into a welder outlet..... you won’t be happy with the resulting destruction if you do.

Post by **KYAvion** » Wed Oct 02, 2019 9:23 pm

Okrivia wrote: ↑Tue Oct 01, 2019 8:12 am I understand that a 240volt welder plug has only three prongs (I believe two hots and a common). Am I correct so far? If so, what about the ground? Does a welder not have a ground wire?

Odds are the 3 prong welder plug has two hots and a neutral, and the neutral also serves as a ground. The prong for a ground is typically a curve or u shape, whereas the prong for neutral is probably a right angle shape on a 3 prong plug. Bottom line as Razorback said, a 3 prong 50 amp receptacle is not ok for your Avion. You need two hots, a neutral, and a separate ground for 50 amp RV service. The neutral should be sized the same as the hots.

AVION Travel Trailers