Plug-in subpanel?

Old 10-02-14, 02:19 PM
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Lightbulb Plug-in subpanel?

I currently have a 50A breaker in my main panel feeding a welder outlet ~5ft away w/ 6-3+gnd wire. Thatís a solid setup and I donít want to modify it. Now Iím building an electric brewery powered by a 5500w@240v heating element and some smaller accessories (450w@120v motor, 300w@120v motor, numerous sensors). My initial plan is to buy a 50A GFCI spa panel and wire it so it is fed by a short length of 6-3+gnd wire with a welder plug on the end so I canÖ you guessed it, plug it in to my existing 50A welder outlet! Am I crazy for thinking of plugging in a sub/spa panel? My next idea is to feed two breakers (a 30A@240v and a 15A@120v) from the 50A GFCI to a rail mounted inside the very same sub/spa panel. Is this crazy?

The idea behind it is the brewery can be unplugged when not in use, sensitive electrical control components brought indoors and the whole feed is GFCI protected. Iím very open to ideas, suggestions, criticism and maybe even a rant or two about my *gifted* way of thinking. Thanks all. Also, Iím in Ohio if that matters.
Old 10-02-14, 03:04 PM
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A portable power supply is commonly used and nothing wrong with the idea. You could even mount a piece of plywood to a two wheel hand truck and mount your panel and receptacles to the plywood. (Hand Truck would need to be bonded to subpanel if metal.) I'd look around for the cheapest main lug panel since no main breaker is required because the plug serves as your disconnect.
Old 10-02-14, 07:33 PM
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fed by a short length of 6-3+gnd wire with a welder plug on the end
I would use SO or SOJ cable. It's rubber encased with stranded wire instead of NM-B. It's rated for flexible and often used cable whereas NM-B is intended to be installed and left alone. And for the record, you want 6/4 SO cable (4 conductors). But it sounds like you have a plan!

Old 10-02-14, 09:05 PM
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I would use auxiliary circuit breakers in the brewing unit. DIN rail mounted CBs.
Old 10-03-14, 07:07 PM
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I have 2 that I made for my Halloween and Christmas display. I am working on a third to power my deep fryer, heat lamps, and other party related stuff. The one I'm showing you is a Square D QO 6-space outdoor panel fed with 6/4 SO cable and has a 14-50 male plug. I have 3 20A breakers feeding 20A GFCI receptacles, a 2-pole 30A breaker feeding a L14-30 receptacle for the deep fryer, and 2 20A GFCI breakers feeding a split duplex. The box with the flipper cover on the side houses a timer which controls 2 2-pole contactors for 4 of the receptacles.

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