3-phase mess...

mhix · June 22, 2016, 4:14pm

Good afternoon all,
Just inspected a co-op unit with 3-phase power (10 awg, 4-wire).

The panel in the unit is a single phase panel rated for 100 amps (with 100 amp main breaker). Two of the service conductors are attached to the 2 main lugs, with the neutral on the neutral bar. The fourth wire is taped off, hanging in the panel.

The main disconnect is in the hallway, so the panel in the unit is a distribution panel. Hallway panel has three breakers, all in the on position, with no amperage rating on the breakers. Panel is sealed, so I can’t take off the dead front.

I don’t see many 3-phase panels, so it’s not my forte, but this all just seems wrong to me.

How should I describe the total amperage? Am I right to say the main breaker in the unit is over-fused?

Thanks in advance for any feedback.

Jim_Port · June 22, 2016, 5:14pm

Do you have pictures?

rcooke · June 22, 2016, 5:25pm

mhix:

Good afternoon all,
Just inspected a co-op unit with 3-phase power (10 awg, 4-wire).

The panel in the unit is a single phase panel rated for 100 amps (with 100 amp main breaker). Two of the service conductors are attached to the 2 main lugs, with the neutral on the neutral bar. The fourth wire is taped off, hanging in the panel.
…Is the 4 wire live or could this be a case of the only cable they had was 4 wire .
The main disconnect is in the hallway, so the panel in the unit is a distribution panel. Hallway panel has three breakers, all in the on position, with no amperage rating on the breakers. Panel is sealed, so I can’t take off the dead front.

I don’t see many 3-phase panels, so it’s not my forte, but this all just seems wrong to me.
…More info needed .
How should I describe the total amperage? Am I right to say the main breaker in the unit is over-fused?

Thanks in advance for any feedback.

Number ten wire can not carry 100 amps ,
Recommend they get an electrician to open Main feed panel and examine and repair if necessary

mhix · June 22, 2016, 5:31pm

main breaker in panel in unit:

abandoned 4th wire in panel in unit:

3-phase panel in hallway feeding panel in unit:

mlarson · June 22, 2016, 5:34pm

I don’t see any 3-phase in use

mlarson · June 22, 2016, 5:39pm

The 100 breaker is a disconnect NOT protection.

3 circuits in the appartment fed with with that pair of 10AWG

mhix · June 22, 2016, 5:50pm

Michael,
The entire panel is fed with the pair of 10awg. Electric range, dryer, other appliances, all lights/receptacles, everything in apartment.

Jim_Port · June 22, 2016, 5:56pm

Something is wrong . You do not have enough power available to run what you just listed. The electric stove should have a 40 or 50 amp circuit.

pabernathy · June 22, 2016, 6:20pm

I agree with Jim…something does not seem right here. First of all that panel looks to be MUCH newer than the hallway panel that is “supplying” it…Second, no way possible that 10 AWG is feeding an electric stove and dryer and other needs in that unit.

Just in terms of NEC minimums…it does not meet compliance with Section 225.39(D) at the least. So without going into too much detail I would indeed defer this one to be reviewed by a licensed electrical contractor…something smells with this one.

it just doesn’t fit…Add up if you will.

mhix · June 22, 2016, 6:26pm

Thanks, all. I really appreciate your expertise and feedback.

The unit definitely doesn’t have enough power. The range is indeed on a 40 amp circuit.

mlarson · June 22, 2016, 7:25pm

You have not shown us an interior view of the panel in the unit beyond the 100 at the top.

something is missing.

rmeier2 · June 22, 2016, 8:15pm

I agree with Michael, more photo’s of the panel are needed especially one that shows the entire interior.

kramm · June 22, 2016, 10:12pm

Hmmm any more pictures.

mhix · June 23, 2016, 12:12am

Got a few reports to write but will post some more pics when time permits.