Panel Mains Question

[dktool]

My main panel has 2 main breakers, 1 feeding left breakers and the other feeding the right breakers.

Is it possible to use one side for loads connected to a back up generator ( non bonded neutral ) and leave the other side powered by the grid or will 2 power sources make the utility neutral leg freak out ?

I know that "fool proof" Isolation lock outs must be in place to prevent backfeed of p1 and p2 from the generator but am unsure of the potential neutral issue.









 

[12VoltInstalls]

My main panel has 2 main breakers, 1 feeding left breakers and the other feeding the right breakers

That should be linked / connected breaker.
I’d keep it holy.

Instead, use the top left breaker positions for using a backfed breaker with a generator lockout device

Is it possible to use one side for loads connected to a back up generator ( non bonded neutral ) and leave the other side powered by the grid or will 2 power sources make the utility neutral leg freak out

that’s not the actual concern or concerns.
Electricity (other than lightning or the balls of electrons that bounce across the floors of the Mount Washington Observatory) only has current in a circuit.
The generator would need to be unbonded unless other isolation provisions are in place.

 

[dktool]

This is an accurate drawing of the way this panel is built.
The generator input breakers (2 pole each) will be installed directly below each of the mains with slide type physical interlocks.
6/4 romex to be used for input with 40 amp breakers.

 

[dktool]

Excuse the R/L error on the left main.

 

[Mattb4]

My main panel has 2 main breakers, 1 feeding left breakers and the other feeding the right breakers.






Most panels the L1 and L2 legs alternate left and right. This allows 240vAC in a double breaker. Your feed in (service breakers) thus power both left and right sides and not just left or right per pole.

 

[dktool]

Correct, each main powers both legs (240) on that pair of bus bars.

 

[12VoltInstalls]

Your feed in (service breakers) thus power both left and right sides and not just left or right per pole.

Correct, each main powers both legs (240) on that pair of bus bars.

This is USA?

And am I an idiot? I don’t see how this works out unless it’s a subpanel for 240V services? No neutral aka no 120V?
Or do I need to look at this again in the morning…

That should be linked / connected breaker.

 

[DPC]

This is USA?

And am I an idiot? I don’t see how this works out unless it’s a subpanel for 240V services? Or do I need to look at this again in the morning…

I cant remember who made that but yes I have seen it before.
Ill get a picture one of these days I know where there is one on my street I've worked on before.

 

[dktool]

That drawing I made is only showing the hots, I have a pic I will find.
Yes, U.S. as in Covina, CA.
Original install from 1957 construction in L.A. County.
Zinsco breakers.

 

[dktool]

 

[12VoltInstalls]

1957 construction

Well that probably explains it.
I’m not an electrician so I haven’t seen “everything,” mostly new stuff, but that config is def foreign to me.

 

[dktool]

So to confirm what I believe is true, if the input main on the right side (yellow 50 amp) is turned off and the gray 40 amp generator input is turned on, the branch circuits on that side can share the grid neutral as long as the generator neutral is not ground bonded.
The left side branch circuits would remain powered by the grid.