Main electrical panel with field installable main circuit breakers before the main disconnect breaker

J

Jimmywhistle

Member
Location
California
Occupation
Electrical contractor
I have 200 amp residential combo distribution panel Murray model number JL230RS. It has a sub-panel circuit breaker installed above the main panel disconnect. When the main disconnect is de-energized that breaker is still powered up since it's located before the main disconnect. I've never seen this before and I don't believe it's very common but is it still legal. House was built around 2002 or 2003. In the image the sub panel breaker has been removed.
https://drive.google.com/file/d/1TIrn7suW4ptZOERlpcG1YDb8wQTfynle/view?usp=drivesdk
 
Sounds like an old style split-bus panel that had a "main lug section" and a switched section.

I have not looked at the pictures.
 
yes it seems to be a split bus panel. But the 200 amp breaker to the lower section seems large. I recall it being 60 amps or so
 
It's not a split bus panel of the old type. Those are simply spaces for 1-2 additonal service disconnects (check the label). These are still legal except that the 2020 NEC required new service panels to have such breakers in separate compartments without an exception for existing panels that compliant when installed. However the 2023 NEC does contain such an exception.

Looks to me like it might be a 400A rated device in total, but I didn't research the model number.
 
Looks like it allows you to have an additional service disconnect. As JB Asked what does the label on the panel show?
Screenshot 2025-01-16 at 07-31-38 Instagram photo by James Vesely • Jan 15 2025 at 7 23 PM.png
 
There was a 100amp CB in the position that feeds a sub panel which has no main breaker on it. Since I had open spaces I decided to move the breaker to lower section. It was a bit disconcerting that the sub panel wasn't marked to indicate that the main service disconnect did not interrupt the power to the sub panel and the CB on the main panel was not marked main disconnect as well. I guess this would be okay under the tap rule, if labeled properly?
20250115_183011-EDIT.jpg
 
Jimmywhistle said:
There was a 100amp CB in the position that feeds a sub panel which has no main breaker on it. Since I had open spaces I decided to move the breaker to lower section. It was a bit disconcerting that the sub panel wasn't marked to indicate that the main service disconnect did not interrupt the power to the sub panel and the CB on the main panel was not marked main disconnect as well. I guess this would be okay under the tap rule, if labeled properly?
Click to expand...
So there originally was a 100 amp breaker above the 200 amp breaker in the photo? Nothing wrong with that you just had two service disconnects. No tap rules would apply. Also if the sub-panel was in the same structure it can be MLO type without a main. Not sure what you mean by the bold because there were two service disconnects not one "main".
 
It's a 300A rated device. So it can totally have a 200A service disconnect plus a 100A service disconnect. The label refers to having two service disconnects. With everything going through a 200A breaker how would it supply 300A?

As an electrical contractor you should be familiar with the "six handle rule". See 230.71.
 
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