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I am putting in a 6-space 100-amp outside box with three 20-amp and two 30-amp breakers.

None of the new breakers are double-pole or 240V.

There is a 10/2 cable running there (formerly used for the double pole 30A, perhaps not the best possible installation, but there it is).

Can I hook up the three wires in the /2 cable (hot, neutral, and ground) to the panel wiring only one side/leg and then run a jumper wire to the other side?

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    Hello, and welcome to Home Improvement. It's a little hard to understand your question; would you add a bit more info (and a period or two)? – Daniel Griscom May 18 '20 at 17:06
  • all videos I see show a 4 wire system 2 black (hot) wires I only have 1 hot wire is it ok to jumper the hot wire to the other side of the box – robert A hummer May 18 '20 at 17:15
  • The op wants to run the entire panel on 120v , a jumper is needed from the hot buss to the other buss. This is what @ Harper is saying is ok I agree. – Ed Beal May 18 '20 at 18:47
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    OP I've made some edits to your question, based on what I think you mean. Please review and edit further if I'm wrong. – Harper - Reinstate Monica May 18 '20 at 19:48
  • Are you putting this panel inside or outside? – ThreePhaseEel May 18 '20 at 23:51
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Yeah, that's fine, but you'll have to rearrange things a bit to make it work.

However, you'll need a disconnect switch

The best way to get that is to fit one more breaker, and backfeed it. (i.e. the supply comes in where the power normally goes out).

A backfeed breaker requires a tie-down kit to be applied. Tie-down kits only fit on 2-pole breakers. (it's called "pole" by the way).

Normally, you would split the feed, e.g. with a wire nut and 2 pigtails, to this 2-pole "master" breaker.

I'm not sure why you're getting such a small panel (in terms of spaces). But since you are out of spaces, we can do a trick. On the 2-pole breaker, one side is the backfeed side from supply. The other side is one of your 30A loads that you mentioned. So this breaker is serving as both the disconnect switch and a branch circuit load. Not elegant, but it will work.

"But wait. I am only backfeeding one leg. How does power get to the other leg?"

Surely this panel has main lugs. You run a wire from one main lug to the other. I recommend a #3 Cu wire since it is a 100A panel after all. But a #10 would be safe for now.

Okay, okay, I hear you on "big panel". How do I wire that?

If the new panel has a main breaker, use that for the disconnect switch. Simply put two #10 pigtails on the two "hot" terminals and wire-nut them to your #10 wire coming in. (use a big tan or red wirenut).

If your panel is "main lug", you still need a disconnect switch, so you'll be forced to backfeed a 2-pole breaker again. Since you have the space, go ahead and get a 2-pole breaker with tiedown kit, and do the "two #10 pigtails" thing as described in the last paragraph. (we didn't do that with the 6-space panel because there wasn't room).

Then proceed normally.

Remember do not put MWBC (shared neutral) circuits in a 120V panel.

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  • Apparently you understand the question. I'd appreciate it if you'd update it (and the title) so the rest of us are on board. – isherwood May 18 '20 at 18:17
  • I'm wondering if an Altech EK12 with a row of Eaton FAZ-NAs and matching busbar kit might be better for this application, as apparently some folks plotz at the use of a split-phase panel in a single-phase app... – ThreePhaseEel May 18 '20 at 23:53

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