Main breaker location

[sparkync]

I have a job that's going to have 2 accessory buildings on the same residential property. In each building, I'm planning on putting a small panel. Will these panels have to have main breakers in them or can I use main lugs. Also if you could give me the code reference I would appreciate it. I'm still looking but can't seem to find it. Thanks

 

[qcroanoke]

I have a job that's going to have 2 accessory buildings on the same residential property. In each building, I'm planning on putting a small panel. Will these panels have to have main breakers in them or can I use main lugs. Also if you could give me the code reference I would appreciate it. I'm still looking but can't seem to find it. Thanks

225.30 through 225.32.

 

[sparkync]

According to 225.33 then, if the subpanel has more than circuit breakers, it must have a main. What if the panel does not have more than 6 breakers now, but has the space for more later? Thanks

 

[K8MHZ]

According to 225.33 then, if the subpanel has more than circuit breakers, it must have a main. What if the panel does not have more than 6 breakers now, but has the space for more later? Thanks

You can have more than six, the rule is 6 or less to completely shut off the building.

For instance, the first sub panel would have up to 6 throws. One of those throws could be for another panel that has more breakers in it.

I have had inspectors interpret the rule as 6 places, and others not.

 

[K8MHZ]

Another option would be to back feed the main lug panel so you would have a main breaker.

But, I have seen panels marked 'MLO' or main lug only. Does that mean you can't back feed them???

 

[jazer]

Main Lug Only means no means for adding or installing a main breaker, hence, no backfeeding with a "Main" breaker. Don't try and create loopholes using the verbage of the code. Essentially, the "feeder" is the service to this disconnected building or structure, if you install a panelboard that utilizes, or could utilize more than 6 breakers or throws, then you need a "main" to disconnect the structure in less than 6 throws.

 

[petersonra]

Main Lug Only means no means for adding or installing a main breaker, hence, no backfeeding with a "Main" breaker. Don't try and create loopholes using the verbage of the code. Essentially, the "feeder" is the service to this disconnected building or structure, if you install a panelboard that utilizes, or could utilize more than 6 breakers or throws, then you need a "main" to disconnect the structure in less than 6 throws.

AFAIK - MLO means there is no provision for a main breaker. You can still backfeed.

 

[Dennis Alwon]

Be careful here as the code states 6 disconnect rule will apply however 225.36 states that the disconnect must be suitable as a service equipment. Most main lug panel are suitable for service equipment only when a main breaker is install. So basically a main is going to be required and hopefully our mod Chris's (Raider) proposal will be accepted and this section will not be the same in the 2014.

Also credit to Don (Resqcapt) for the info on the main breaker being required to fulfill this requirement as service equipment. I never noticed it.

 

[jazer]

AFAIK - MLO means there is no provision for a main breaker. You can still backfeed.

Maybe I am interpreting this wrong, but 408.36(D) speaks of additional fasteners being required to install a device used to backfeed a panel. When a panel is rated MLO, it does not provide any listed means for additional fastening of a backfed "main". So again, I do not believe that it is permitted to backfeed an MLO panel.

Just sunk in about the "plug-in" devices. I suppose a bolt on breaker would be alright.

 

[Cow]

I've done a ton of installs using a MLO with a backfed main. It serves the purpose and satisfies code.

If you can't backfeed breakers in a MLO, why do they make retainer kits for them?

 

[petersonra]

Be careful here as the code states 6 disconnect rule will apply however 225.36 states that the disconnect must be suitable as a service equipment. Most main lug panel are suitable for service equipment only when a main breaker is install. So basically a main is going to be required and hopefully our mod Chris's (Raider) proposal will be accepted and this section will not be the same in the 2014.

Also credit to Don (Resqcapt) for the info on the main breaker being required to fulfill this requirement as service equipment. I never noticed it.

I thought the only difference between service equipment and not service equipment was provision for running the green screw through the neutral bar into the panel.

Why couldn't you do that on an MLO panel. I have seen MLO panels that actually came with stickers that you could add that said it was service equipment if you used it that way.

So is there a newish rule that says service equipment has to have a main breaker?

 

[don_resqcapt19]

Maybe I am interpreting this wrong, but 408.36(D) speaks of additional fasteners being required to install a device used to backfeed a panel. When a panel is rated MLO, it does not provide any listed means for additional fastening of a backfed "main". So again, I do not believe that it is permitted to backfeed an MLO panel.

Just sunk in about the "plug-in" devices. I suppose a bolt on breaker would be alright.

Most MLO panels have a means to comply with 408.36(D). The additional fastening is an accessory item and not part of the panel or the breaker.

 

[don_resqcapt19]

... or could utilize more than 6 breakers or throws, then you need a "main" to disconnect the structure in less than 6 throws.

There is nothing in the code to support the idea that if you "could" install more than six breakers, then you need a main.
The only issue is if the panel is suitable for use as service equipment without a main and if there are six or less breakers installed at the time of the inspection.

 

[Dennis Alwon]

I thought the only difference between service equipment and not service equipment was provision for running the green screw through the neutral bar into the panel.

Why couldn't you do that on an MLO panel. I have seen MLO panels that actually came with stickers that you could add that said it was service equipment if you used it that way.

So is there a newish rule that says service equipment has to have a main breaker?

No new rule but the equipment, for some reason, states that it is only suitable as service equipment when installed with a main breaker kit. Why I don't know as it looks just like any other panel structurally. I have also never met an inspector who checked it out but I usually use a backfed main with hold down kit.