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I need to wire 4 220 Volt Inverter ACs, a 220 Volt Water Heater, and a 220 Volt well pump. I'd like to have at least 2 empty spares. What type of BR Breaker box should I look for? Is something like a 12 space, 24 circuit 125 amp box ok?

I was recommended a GE 125 Amp outdoor copper bus 12 spaces 24 circuits model TLM1212RCU. One of the breakers recommended was a 50 amp 1 inch double pole model BR2GETHQP250.

  • Where is this panel going? – ThreePhaseEel Aug 8 '18 at 23:19
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    The "circuit" number means nothing, since it relies on use of tandem or double-stuff breakers. Most circuits today require AFCI or GFCI, which do not come in double-stuffs, so you paint yourself into a corner real quick. Because of that, most of us preach wildly oversizing the panel - seriously, you cannot buy too many spaces. Spaces are cheap, regrets are expensive. – Harper Aug 8 '18 at 23:28
  • In order for anyone to size a panel for you. You need to give the RLA (run load amperage), HP, or KVA (KW) of the inverters, water heater, and the well pump. If you don't you are just taking a chance on selecting the right size panel. – Retired Master Electrician Aug 9 '18 at 15:52
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12 spaces is OK for this, but 20 or 24 spaces would not be out of place

A 12 space panel is a bit small, but OK for this job, given that you'll be using main lugs here. I would upsize to a 20 or 24 space unit though if at all possible -- as Harper said, "Spaces are cheap, regrets are expensive."

I'd stay in the BR line, however

Whoever recommended you a GE panel, though, was silly, and that breaker P/N isn't even a valid Eaton part number! (The correct Eaton P/N for a 50A two-pole breaker for that panel is CL250, BTW, and the corresponding native GE breaker for that would be a THQL2150.) I'd just get something like a BR2424L125G for this (provided it's indoors -- the outdoor counterpart is a BR2424L125R, but you'll need to field fit the grounding bar yourself in that case).

Don't forget the details

Make sure you pull the bonding Z-strap in the new subpanel, and also torque all the panel and breaker lugs to manufacturer's specs with an inch-pound torque wrench!

  • What would be the purpose of removing the Z-strap? – Rick Aug 9 '18 at 20:59
  • @Rick -- the Z-strap connects neutral to ground in a main panel on the Eaton BR line, so it needs to be disconnected or removed when the panel is used as a sub – ThreePhaseEel Aug 9 '18 at 22:07
  • Even if neutral and ground are already bound together on the main breaker at the electric meter? – Rick Aug 9 '18 at 22:10
  • @Rick -- that's exactly why the Z-strap gets removed from the subpanel. neutral-ground bonds are like the Highlander -- there can only be one ;) (unless you have separately derived system shenanigans going on, but those are a whole another story) – ThreePhaseEel Aug 9 '18 at 22:15
  • Would I need a grounding bar for this subpanel? Or can I just connect ground cables to the ground side bar? – Rick Aug 9 '18 at 22:17

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