Garage sub panel MCB required

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csoc64

Senior Member
Location
northeast
Looking at a new 32 circuit sub panel in a detached garage which is fed from a 100A breaker from the main panel in the house. I was under the impression that this required a MCB in the panel because it was in a detached structure, but have not been able to locate applicable code (2014). Does it matter if it has 6 or fewer branch circuit breakers?
 

Bill Annett

Senior Member
Location
Wheeling, WV
Occupation
Retired ( 2020 ) City Electrical inspector
Good morning. I do not have a 2014 NEC but article 225.31 ( Main Disconnect ) and article 225.32 ( state that you also follow the requirements in 230.6 ) in the 2011 NEC might help you out. Article 225 deals with outside branch circuits and feeders.
 

kwired

Electron manager
Location
NE Nebraska
2014 NEC 225.33 limits you to six disconnecting means (as a general rule, there are other circumstances that can allow more then six) in the separate structure.
 

templdl

Senior Member
Location
Wisconsin
Looking at a new 32 circuit sub panel in a detached garage which is fed from a 100A breaker from the main panel in the house. I was under the impression that this required a MCB in the panel because it was in a detached structure, but have not been able to locate applicable code (2014). Does it matter if it has 6 or fewer branch circuit breakers?
Is the cost of a main breaker panel too costly? Or are you trying to install the very minimum as required.
Opt for the main breaker panel and call it a day unless you are penny pinching.
 

Ponchik

Senior Member
Location
CA
Occupation
Electronologist
A panel that has the main breaker pre installed is usually more $$ than a regular panel that you install "a" breaker in two of the slots and that will act as your main disconnect. Of course the panel must have the feature of bolting the breaker to the panel.

But in general as stated by Kwire you will need a main disconnect for the detached structure unless you have less than 7 disconnects. IMO, even if you have less than 7 disconnect but your panel has more capacity, you still need the main disconnect.
 

jaggedben

Senior Member
Location
Northern California
Occupation
Solar and Energy Storage Installer
One could put a separate disconnect ahead of the panel if that's an easier way. It only has to be a disconnecting means, not overcurrent protection.
 

ActionDave

Chief Moderator
Staff member
Location
Durango, CO, 10 h 20 min from the winged horses.
Occupation
Licensed Electrician
Is the cost of a main breaker panel too costly? Or are you trying to install the very minimum as required.
Opt for the main breaker panel and call it a day unless you are penny pinching.
I opt to go without a main breaker every time if it's not required, and not for reasons of penny pinching. They take up space for one thing.
 

kenman215

Senior Member
Location
albany, ny
I opt to go without a main breaker every time if it's not required, and not for reasons of penny pinching. They take up space for one thing.

True, however OP was looking at 100A, 32 circuit panel. I don't know why you'd get a load center with that many circuits unless you were planning on using quite a few of them. MCB might cost you an extra $50 over the same size subbanel, but the job would have to be pretty damn small to make that too high of a percentage of total cost to make it not worth getting it instead, IMO..
 

ActionDave

Chief Moderator
Staff member
Location
Durango, CO, 10 h 20 min from the winged horses.
Occupation
Licensed Electrician

True, however OP was looking at 100A, 32 circuit panel. I don't know why you'd get a load center with that many circuits unless you were planning on using quite a few of them. MCB might cost you an extra $50 over the same size subbanel, but the job would have to be pretty damn small to make that too high of a percentage of total cost to make it not worth getting it instead, IMO..
For this application it's a good thing. I got side tracked between this thread and another current one about a basement sub panel.
 

jaggedben

Senior Member
Location
Northern California
Occupation
Solar and Energy Storage Installer
Agree, but more work and probably more expense (most of the time)

Yes to 'most of the time', but if one is fixing an existing code violation where the panelboard is full and/or does not have provisions for adding a main breaker, then the disco may be your fix.
 
A panel that has the main breaker pre installed is usually more $$ than a regular panel that you install "a" breaker in two of the slots and that will act as your main disconnect. Of course the panel must have the feature of bolting the breaker to the panel.

For the brand of loadcenters I usually use, It is usually CHEAPER to buy a MB than a MLO. Granted maybe that changes for the less common configurations. 100A 32 space is a bit of an oddball IMO.

IMO, even if you have less than 7 disconnect but your panel has more capacity, you still need the main disconnect.

You are entitled to your preferences and practices, but the NEC has no such requirement.
 

Ponchik

Senior Member
Location
CA
Occupation
Electronologist
For the brand of loadcenters I usually use, It is usually CHEAPER to buy a MB than a MLO. Granted maybe that changes for the less common configurations. 100A 32 space is a bit of an oddball IMO.



You are entitled to your preferences and practices, but the NEC has no such requirement.


what is not required per NEC?
 

jap

Senior Member
Occupation
Electrician
I you use 2p breakers in conjunctionn with handle ties for single pole breakers you can get a lot of circuits out of 6 movements.


JAP>
 

kwired

Electron manager
Location
NE Nebraska
I you use 2p breakers in conjunctionn with handle ties for single pole breakers you can get a lot of circuits out of 6 movements.


JAP>
18 space panel holds only six three pole breakers but has a fair amount of space left if only installing six single pole breakers.
 
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