Split bus panel

[nizak]

I have an existing 100 amp split bus panel in a residence. I need to get additional breaker space and am looking to install a sub panel next to it.

There is currently the “main lighting” 2 pole breaker feeding the lower bus.

In the factory labeled “main disconnect “openings there is a 2 pole breaker for the range and then 2 single pole breakers.



Is it code compliant to remove the 2 single pole breakers and install a 2 pole breaker to feed the new sub panel?

I could then re feed the 2 single pole loads from the new sub and add my new load.

This set up would allow for all power to be disconnected with 3 double pole breakers.

It’s a 100 amp service, total connected load with new circuits would be 77A.

Thank you.

 

[LarryFine]

Is it code compliant to remove the 2 single pole breakers and install a 2 pole breaker to feed the new sub panel?

Yes, and preferable.

 

[nizak]

Yes, and preferable.

Thank you.

 

[Fred B]

Would be recommending replacement of the split bus system as most are outside mfg. recommended life, or of questionable condition or brand (Federal, Curtis, etc.).
Another consideration adding a sub to the split bus likely will overload the old system max rating of the bus. Lower bus may already be limited to 50 or 60 amps rating.

 

[nizak]

Yes, and preferable.

Would be recommending replacement of the split bus system as most are outside mfg. recommended life, or of questionable condition or brand (Federal, Curtis, etc.).
Another consideration adding a sub to the split bus likely will overload the old system max rating of the bus. Lower bus may already be limited to 50 or 60 amps rating.

Adding it to the upper portion would not subject it to overloading the 50 amp main lighting breaker if that’s your thought.

Pretty certain it’s a 125A rating. Current load calc puts it just under 80A.


I do understand your thinking as far as overall overloading, seem many stuffed full of tandems.

It’s mid 70’s Square D QO and in good physical condition.