Services

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wmeek

Senior Member
When you are installing a 800A Service with six disconnects,is it code not to install a combine rating of the six disconnects to exceed the 800A rating of the service conductors.

Thanks
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Electrical Contractor
When you are installing a 800A Service with six disconnects,is it code not to install a combine rating of the six disconnects to exceed the 800A rating of the service conductors.

Thanks
As long as the calculated load is 800 amps or less there is no reason why the breakers must total 800 amps. You could have 6- 200 amp breakers in the panel if you like.
 

augie47

Moderator
Staff member
Location
Tennessee
what Dennis said ! As long as the service conductors don't terminate in a single OCP device, they are sized to the calculated load, not the sum of the devices
 

wmeek

Senior Member
So you are saying that if you have an 800A service conductors in a gutter with 6-200A disconnects that that would be code. If so you could load the services conductors beyond there capacities with future addititions
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Electrical Contractor
So you are saying that if you have an 800A service conductors in a gutter with 6-200A disconnects that that would be code. If so you could load the services conductors beyond there capacities with future addititions
Funny huh but that is correct.
 

pete m.

Senior Member
Location
Ohio
Funny huh but that is correct.
When utilizing 230.90(A)exc.3, assuming you have a 2000 amp rated service with 6 400 amp breakers installed and a calculated load of 200 amps, could you feed this service with 3/0 CU?

The reason I'm asking is that I debated this with a gentleman that stated that no single OCPD (out of the allowable six) could exceed the ampacity of the service conductors. I am not of that opinion although I am also not very fond of this type of installation.

Pete
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Electrical Contractor
When utilizing 230.90(A)exc.3, assuming you have a 2000 amp rated service with 6 400 amp breakers installed and a calculated load of 200 amps, could you feed this service with 3/0 CU?
Pete
If you did that then you would not have a 2000 amp service. Your service would be 200 amps regardless of the ampacity of the panel as long as there is not a single OCPD.
 

pete m.

Senior Member
Location
Ohio
If you did that then you would not have a 2000 amp service. Your service would be 200 amps regardless of the ampacity of the panel as long as there is not a single OCPD.
You are correct... I should have clarified that the bussing in the service equipment is rated at 2000 amps.:grin:

What is your opinion on the debate that I described?

Pete
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Electrical Contractor
You are correct... I should have clarified that the bussing in the service equipment is rated at 2000 amps.:grin:

What is your opinion on the debate that I described?

Pete
I stated that it does not matter what the buss size is it depends on the service conductors- so I still think it is a 200 amp service. I can have a 200 amp sub panel and feed it with 100 amp conductors as long as the wire is protect. In the case of the service there is no reason why you couldn't have a 2000 amp panel and feed it with 200 amps if the calculated load is satisfied. Costly but legal, imo.
 
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