Services

[wmeek]

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]

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]

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]

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]

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.]

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]

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.]

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]

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.

 

[defears]

Think of it this way.
200 Amp panel with 42 single pole 20 amp breakers.
Is this a 840 amp panel.

 

[jxofaltrds]

Think of it this way.
200 Amp panel with 42 single pole 20 amp breakers.
Is this a 840 amp panel.

Good example. HOs ask about this all the time.