Disconnecting Means in Main Lug panel

[Doc13067]

I am installing a sub panel in a detached garage. I have a 4 space main lug load center. Obviously this is no good because I need a disconnecting means. Can I install a breaker and run my feeders to the breaker and leave the lugs unoccupied and install a hold-down on the breaker? This is getting inspected so I need to make sure it’s right before the inspection.

 

[macmikeman]

Yes . But most brands the hold down's only work with larger amp double or three pole breakers. So there is that as well to deal with.

 

[LarryFine]

Which code? Six or fewer breakers do not need a main disco.

 

[Doc13067]

Which code? Six or fewer breakers do not need a main disco.

225.31 and 225.32. Am I missing something? I checked the exceptions and don’t see my scenario in them.

 

[Doc13067]

Yes . But most brands the hold down's only work with larger amp double or three pole breakers. So there is that as well to deal with.

In that case, Do inspectors generally mind if you put a 100 amp breaker on a panel like this if it is fed from a 40 amp breaker back in the main?

 

[petersonra]

In that case, Do inspectors generally mind if you put a 100 amp breaker on a panel like this if it is fed from a 40 amp breaker back in the main?

Why would they care? It is perfectly code compliant.

 

[infinity]

As Larry stated you can apply the 6 disconnect rule and eliminate the main. If you install a 2 pole main that only leaves 2 circuit slots in the 4 space panel. Not the best design IMO.

Wait a min.... you're running feeders from a main panel to a sub panel? As long as you are protecting the feeders with a 100A breaker (or whatever size you choose)in the main panel, you don't need a "main" breaker in the sub panel. I'm assuming that the panel is not leaving your building (house?)

He said that it's a detached garage.

 

[Rock86]

As Larry stated you can apply the 6 disconnect rule and eliminate the main. If you install a 2 pole main that only leaves 2 circuit slots in the 4 space panel. Not the best design IMO.

He said that it's a detached garage.

Yeah... after reading the replies i missed that part.

 

[Doc13067]

Ok so then I’m ok to put a main lug panel but just run the feeders to a breaker and install a hold down and not use the main lugs?

 

[petersonra]

Ok so then I’m ok to put a main lug panel but just run the feeders to a breaker and install a hold down and not use the main lugs?

That would be okay but I'm not sure it's absolutely necessary.

 

[infinity]

Ok so then I’m ok to put a main lug panel but just run the feeders to a breaker and install a hold down and not use the main lugs?

As long as the main lugs are suitable for the feeder conductor size I see no need for a main when you have only a 4 circuit panel. Don't forget the grounding electrode system.

 

[Doc13067]

I’m just looking at the code that states a detached building needs a local disconnect means. But ok thank you. And yes I’ve already got ground rods driven at the garage as well as at the service entrance. Thanks for all the help!

 

[infinity]

I’m just looking at the code that states a detached building needs a local disconnect means. But ok thank you. And yes I’ve already got ground rods driven at the garage as well as at the service entrance. Thanks for all the help!

Yes, but you can have up to 6 disconnecting means so with a 4 circuit panel you do not need a single main.

 

[Doc13067]

Yes, but you can have up to 6 disconnecting means so with a 4 circuit panel you do not need a single main.

Interesting ok can you direct me to that in the code so I can look at it and understand it for myself?

 

[roger]

Interesting ok can you direct me to that in the code so I can look at it and understand it for myself?

As Larry asked, what code cycle?

Roger

 

[infinity]

Interesting ok can you direct me to that in the code so I can look at it and understand it for myself?

225.33 Maximum Number of Disconnects.
(A) General. The disconnecting means for each supply permitted by 225.30 shall consist of not more than six switches or six circuit breakers mounted in a single enclosure, in a group of separate enclosures, or in or on a switchboard or switchgear. There shall be no more than six disconnects per
supply grouped in any one location.

 

[Doc13067]

As Larry asked, what code cycle?

Roger

2014

 

[LarryFine]

No main breaker required.

 

[infinity]

As Larry asked, what code cycle?

Roger

Has the requirement changed for later code cycles?

 

[roger]

I hear it has in the 2020.

Roger