Sub panel circuit breaker

[coffeebean]

Customer has 150amp main circuit breaker in a panel that is rated for 200amps (single phase residential underground service) he has a 200amp circuit breaker feeding a sub panel rated at 200amps fed with three 3/0 and #4 ground.My question is does the sub panel breaker have to be 150amps or can I leave it the way it is due to the fact the panel is rated 200amps

 

[augie47]

as long as your conductors have proper overcurrent protection (either the main or branch breaker)
at their supply, the downstream panel can have any rating equal or greater than the OCP supply device.
(Your sub-panel could be a 400 amp or 600 amp, etc. )

 

[Dennis Alwon]

Please explain--- 150 Main breaker and then a 200 amp breaker from that panel to another panel???? If that is so I would question whether that buss can take a 200 amp breaker and be compliant with the listing. Most 200 amp panels will only allow a 125 amp breaker on the bus bar.

BTW how is a panel rated underground unless this is a meter main combo unit.

 

[charlie b]

BTW how is a panel rated underground unless this is a meter main combo unit.

The word "underground" is associated with the service conductors, not the panel's rating. :happyyes:

 

[Dennis Alwon]

The word "underground" is associated with the service conductors, not the panel's rating. :happyyes:

:? What does that mean? :?

 

[Cow]

I'd like to know why a guy would feed a sub with 3/0 Cu?? I'm assuming when the main panel is only a 150A unit. Why install 200A wire? I wouldv'e installed a subfeed lug kit right in the 150A panel and saved the cost of an expensive 200 amp breaker.

BTW how is a panel rated underground unless this is a meter main combo unit.

He didn't say the panel is rated "underground" he simply said he had a service rated at 200 amps single phase that's fed underground.

 

[augie47]

I'd like to know why a guy would feed a sub with 3/0 Cu?? I'm assuming when the main panel is only a 150A unit. Why install 200A wire? I wouldv'e installed a subfeed lug kit right in the 150A panel and saved the cost of an expensive 200 amp breaker.

Certainly would not be "normal", would it ?
It's possible the feeder is existing and he's is re-connecting it to a new source. ??
Perhaps the OP will elaborate.
I join Dennis in being curious as to finding a panel with a 150 amp main and 200 sub-feed breaker.

 

[coffeebean]

The customer wanted to relocate existing branch circuits and future circuits to the sub panel in the basement for easier access.He is renovating his home and I just came on board this week with the renovation well under way. It is a one story home but he is installing an elevator that goes from the basement to the first floor just so he can remove the basement steps for more storage in the basement and a laundry room on the first floor.He is a retired gentleman with too much time and money.

 

[augie47]

The customer wanted to relocate existing branch circuits and future circuits to the sub panel in the basement for easier access.He is renovating his home and I just came on board this week with the renovation well under way. It is a one story home but he is installing an elevator that goes from the basement to the first floor just so he can remove the basement steps for more storage in the basement and a laundry room on the first floor.He is a retired gentleman with too much time and money.

Yes, Virginia there is a Santa Claus

 

[Dennis Alwon]

The word "underground" is associated with the service conductors, not the panel's rating. :happyyes:

I guess I am slow-- I thought he was talking about a meter main combo. Some of them are only rated for underground service but having a meter main combo changed things. I finally got it. :ashamed1:

 

[kwired]

150 or 200 amp breakers installed in a 225 amp or less panelboard are somewhat rare but many manufacturers have such a breaker available. They often cost more than the panel even with main installed, and usually take four spaces or six for a three phase unit. The breaker may not be listed to install in just any panel though. Wire bending space at terminations can be part of the reasoning.

 

[coffeebean]

kwired you are correct it is a Murray panel and the 200amp breaker takes up four pole spaces the 3/0's have a tight radius at the termination

 

[donaldelectrician]

I join Dennis in being curious as to finding a panel with a 150 amp main and 200 sub-

I join Dennis in being curious as to finding a panel with a 150 amp main and 200 sub-

What ever happened to Selective Coordination !

Let alone if Pan can take a 200A Sub CB !





Donald " Outstanding Citizen of the Conch Republic "

 

[kwired]

What ever happened to Selective Coordination !

Let alone if Pan can take a 200A Sub CB !





Donald " Outstanding Citizen of the Conch Republic "

You don't do much residential or light commercial do you? Sure it may not make a lot of sense. It was probably what was easiest or cost the least at the time. Some pans will accept a 200 amp breaker, some will not. Some will accept it but are not listed to accept it.

 

[acrwc10]

To answer the Original Post, if you have a 150 main breaker and the conductors are sized to feed 150 amps to the distribution panel, you can put any size disconneting/ main breaker you want on that panel. The secondary breaker is only acting as a disconnect not an over current devise.
Murry sells a panel that is an MLO that you can add a main breaker to replace the main lugs. The cost is good and they sell 100 -125- 150- 200 amp main breakers for them. I just bought four of them yesterday, $99.00 for a 30-40 load center and $56.00 for a 200amp breaker.

 

[acrwc10]

I should add they take up no branch circuit spaces because the main bolts into the top of the bussing.

 

[Dennis Alwon]

I think we are talking too things here. Most 200 amp main breaker panels will not accept a 150 amp breaker on the buss bar. Most won't even fit but if you read the info it states that you are limited to "X" amps per stab. In some cases you cannot even put 2- dp 100 amp breakers across from each other as that will not comply with the panel listing.

 

[kwired]

Square D has breakers like what is being discussed in this thread for both Homeline and QO. They have 150, 175 and 200 amp in both lines they take four breaker spaces and can be used in any panel with 150 or greater rating.

http://products.schneider-electric....uctDetail&countryCode=us&partNumber=HOM2200BB


http://products.schneider-electric....roductDetail&countryCode=us&partNumber=QO2200

I could swear I have connected a 3 pole version many years ago, but could not find one in current catalog, maybe no longer made.

 

[Dennis Alwon]

I don't see how those breakers can work as a side mount with 3/0 conductors. I don't think you would have the bending radius. I believe those breakers mount at the top of the panel but I may be wrong. I guess I should say that all the GE and many of the Cutler Hammer residential panels I have seen will not allow that style breaker to be mounted on the bus below the main.

 

[ActionDave]

GE makes a TQ something something that fits in their 200A panels. It takes up four spaces, but not down one side, ie slots 1,3 and 2,4.

I just used one this year.