30 amp 240 downstream from a welder plug

[Specz79]

so after going back and forth I am going with a grounded brewing BIAB controller because I like everything controlled on one panel including the pump. I will be brewing in my garage because I doubt SWMBO will be happy if I did it in the house (my other hobby I used the oven to oven cure paint, she was not impressed with my problem solving skills). I have a sub panel wired in my garage, but at the time I didn’t plan enough ahead and can’t add another 240 circuit. When I put in the garage electrical I had an electrician buddy help me power it and I’m fairly sure we ran 4 wire to ground the sub panel (not sure why we wouldn’t have and I’m not home to pull the panel to check. Let’s assume I’m correct). The welder outlet is only 3 prong and I was wondering if I can run a single sub panel tied to the outlet (50 amps) and put a 30 amp gfci in the single sub panel to power the controller. I am not worried about overloading the 50 amp considering I would never be welding while brewing and would have the 30 amp breaker off when not in use. I might have to run a 4 line to the welder outlet (not connecting the ground to the outlet, but ground the box in the original and running the ground to the single sub then to the 4 wire). Without getting into code discussions will this work and protect the controller at 30 amp with gfci protection as well as allow me to run the 110 pumps? Should be the standard ground common connection in the main box and my garage has a floating common. I know it’s cheaper to run a spa panel but I won’t be able to run the 110 off a welder plug I don’t believe and I don’t want to rewire the controller to have 2 circuits. Sorry, long read, thanks.

 

[Bobby_M]

You definitely want 4 wire to run 120v off the controller. The welder is HHG and you need HHNG, I.e. the neutral is missing. An alternative is to use 240v riptide or chugger pumps or the topsflo 24VDC pump since the power adapter can be fed with 240v.

 

[Specz79]

Right, but I can tie into my neutral out of my subpanel for the 30 amp to get my 120 circuit correct? I.e run my 2 hots and ground from outlet to 30 amp circuit breaker and box and the neutral tied to the floating neutral bar in the sub. Essentially making a single sub panel for a 4 wire plug but just pig-tailing the hots off of the outlet that is protected by the 50 amp. The plug to the 30amp will have its own circuit breaker down line to protect the controller.

 

[doug293cz]

Right, but I can tie into my neutral out of my subpanel for the 30 amp to get my 120 circuit correct? I.e run my 2 hots and ground from outlet to 30 amp circuit breaker and box and the neutral tied to the floating neutral bar in the sub. Essentially making a single sub panel for a 4 wire plug but just pig-tailing the hots off of the outlet that is protected by the 50 amp. The plug to the 30amp will have its own circuit breaker down line to protect the controller.

No. Your GFCI protection will not work if you do this. You will trip the GFCI as soon as you turn on any 120V load. Any neutral needs to route to the neutral connection on the load side of the GFCI breaker.

Brew on

 

[Specz79]

So tie the neutral to the gfci and then the outlet?

ETA: disregard the above, I can just run a second sub panel with a breaker to kill it and then the gfci for the outlet. This will give me the proper 4 wire needed, will probably put me over my amps so probably not to code, but like I said before this is simply for the controller that would not be used when using the welder and both won’t be used simultaneously ever.

 

[stevehaun]

Is there no room for another 240 vac breaker in your subpanel? Why not add a 30 amp, 240 vac gfci breaker to your subpanel and wire a new 4 wire outlet?

 

[Specz79]

I could because I put each wall on its individual breaker and never expected any expansion, especially a 240. It would involve me moving circuits to free up the space though, that’s why I was looking to add another sub as it would be easier to just run a single wire rather than tie others together. Might be easier, I’ll have to look when I get home in a couple weeks.