Thread: Sub panel wiring

Saw this in home today that have never seen before and don't know how to write it up other than it's wrong. There were two sub panels in basement one below the other. Wiring to 120V, 20 amp breakers in lower panel have hots to breakers and neutrals to bar in upper panel?

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Originally Posted by Tom Rees

Saw this in home today that have never seen before and don't know how to write it up other than it's wrong. There were two sub panels in basement one below the other. Wiring to 120V, 20 amp breakers in lower panel have hots to breakers and neutrals to bar in upper panel?

Tom,

Not quite understanding the above.

First, you have a submarine in the basement?

(Okay, let's skip that part. )

You have two PANELS in the basement, right?

Now for the other part I don't follow you:

"Wiring to 120V, 20 amp breakers in lower panel have hots to breakers and neutrals to bar in upper panel?"

Are you stating that the lower panel has the 'hot' feeders fed off a breaker in the upper panel, and, has the 'neutral' feeder tied back to the neutral terminal bar in the upper panel?

If so, what size (rating) is the breaker (double pole) compared to what size rating is the lower panel compared to what size rating of the feeders.

Here is an example:

If the lower panel is rated for 60 amps, the feeders to the lower panel are rated for 60 amps, and the breaker in the upper panel feeding the feeders to the lower panel has a 60 amp rating, then nothing is wrong - provided it is all wired correctly (i.e., grounds connected, neutrals isolated from grounds, no open knocks, no multiple taps, none of the other things we frequently find).

Saw this in home today that have never seen before and don't know how to write it up other than it's wrong. There were two sub panels in basement one below the other. Wiring to 120V, 20 amp breakers in lower panel have hots to breakers and neutrals to bar in upper panel?

The way I'm reading Tom's post is that he has some 20-amp circuits where the hots are connected to breakers in the lower panel but the neutrals for those circuits are run back to and connected at the upper panel's neutral bar. In other words, the circuit hots and neutrals land in separate panels.

If that is the case (Tom?) then "wrong" would be a way to describe it. I might add something about the potential for confusion in that situation leading to the possibility of "open neutral" hazards.

Originally Posted by Tom Rees

Wiring to 120V, 20 amp breakers in lower panel have hots to breakers and neutrals to bar in upper panel?

Originally Posted by Richard Moore

The way I'm reading Tom's post is that he has some 20-amp circuits where the hots are connected to breakers in the lower panel but the neutrals for those circuits are run back to and connected at the upper panel's neutral bar. In other words, the circuit hots and neutrals land in separate panels.

Richard,

I absolutely agree that Tom needs to clarify it.

I don't get what you said from what he said, but - who knows.

Tom, a photo would help, especially a photo showing the two panels and the wiring between them.

Are you saying that the lower panel is backfed from the upper panel?

Originally Posted by Randy Aldering

Are you saying that the lower panel is backfed from the upper panel?

That's what I am thinking (although "backfed" would refer to a breaker being "backfed", not to a panel, the panel would be "fed from", as in the lower panel is "fed from" the upper panel), but not what Richard is thinking.

It is not a problem to do that, when done correctly. And that is key, "when done correctly". If the breaker is "backfed" and serving as a main to the lower panel, then that breaker would need to be secured in place with a screw, bracket, clip or whatever the manufacturer of the panel provided a means to anchor that breaker in place.

FWIW, when I read Tom's post I got the same thing that Richard described -- hots are connected to breakers in the lower panel and the neutrals for those circuits are terminated in the upper panel.

IF the wiring is as decribed above, and IF the upper panel is the main load distribution center, and IF the lower panel is the load distribution center for a generator hookup, then this wiring configuration could be OK, IF the wiring instructions for the generator transfer switch and load center were followed (lots of big IFs there). See the instructions and wiring diagram in the attached pdf for a Gen/Tran unit.

We really do need Tom to clarify things. Photos would help.