Appears confusing

For a Residential panel to have what appears to be a breaker with four wires. I wonder how many new inspectors would miss this or explain its use

3 phase, just guessing.


I bet that property was commercial at one time.

Nope strictly residental

I don’t see 3 phase at the panel (backfed 2-pole breaker), but see the service entrance at 3 phase. I’m all ears on what this set up is.

I would love to know how a residential property got the power company to give them 3 phase. That would be awesome if you want to run a mill in the garage.


Good guess!
That AC data plate confirm a 3 PH unit…

Third phase is being back fed to the bottom phase of the four pole breaker. I’m unclear as to how this works with the rest of the panel. It looks a bit sketchy to me (beyond the lack of retention), but this is one occasion where I would need to defer it to an electrician, because it’s beyond what I deal with day in / day out. While they’re at it they can sort out what’s going on with breakers #15 & 8 and the improperly configured MWBC at #5 & 7 (verify that it’s being fed from separate phases) and multiple apparent handle tie issues.

I would like to hear Paul Abernathy speak to this 3-phase setup with the 4-pole breaker. I don’t think 've ever seen anyone do like that. Seems like it would be a requirement to disconnect all phases together.

To me it violates safety codes because there is no one hand movement disconnecting means because the 3rd leg is still hot at the 4 pole breaker.

This was on a 1955 home that had been added on two too times at least. It was Charley’s house of horrors

This was a roof shot of the neighborhood you can see the service wires at the top of the photo.

Nice find. Did the AC unit actually work? From the shot of the conductors at the pole it appears that two are connected together leaving only three conductors feeding the panel.

Yes the A/C unit ran like a charm

So then something seems to be missing from the equation. You have only three lines feeding the panel but you have a 3Ø, 4W system? Out of curiosity did you happen to check the voltages?

Yes I did check the voltage between the legs and between each leg and the bottom conductor. The volts was reading 250 volts which I though was a little high.

That bottom conductor on the 4 pole breaker was coming straight from the meter base. What I don’t understand was why that conductor was not back feeding to the 100 amp main breaker but it did not appear to be. I would of like to have pulled those breakers and looked at the buss connections but I did not. Turning it over to the sparkies.

Robert I don’t know if you can tell in my Pic’s but at the weather head there are 3 hot conductors, the support cable for the conductors is serving as the ground and the neutral within the panel.

I might add I have done this type of work 20 years inspecting and 40 years in HVAC and I have never run into this type of panel. I have worked with a lot of commercial 3 PH

I did notice that but on the other end, where it’s connected at the pole, the one “hot” is spliced to the bare conductor so in effect you only have 3 different conductors entering the weatherhead. So you have only a 3 wire drop to the panel which doesn’t make sense because the system need 4 wires to operate as a 3Ø, 4W.

BTW very interesting that you posted this especially that “add a phase” breaker at the bottom. :cool:

I see that there is a label on the front of that CB any chance you could find a part number?

That lable was a intertnal diagram no part # and it was faded could not read it