800 amp service

[iwire]

Look familuar Mr.Kwired

It does to me, that is a primitive one line drawing I made of a service that I worked on.

It was a Main lug only switch gear rated 1,600 amps.

 

[electricalist]

Im so sorry I got my wires crossed. No disrespect

 

[iwire]

My reference was the six feeder overcurrent protective device. I see that as part of the question. The feeders make up the load for the service.

I see.

You confused me by bringing up a panel with 40 circuits as that will have a main in front of it ensuring the conductors supplying the panel and the panel itself cannot be overloaded.

In my mind that is the opposite of what we are talking about, we are talking about a situation with no main where only the calculated load and nothing else protects the conductors from overload.

 

[iwire]

Im so sorry I got my wires crossed. No disrespect

No worries, once I post a picture to the internet I assume it will be passed around.

 

[iwire]

Can't say I am familiar with Eaton's products, but that mains cabinet is likley available in 200, 400 and 600 amp versions as well. So whoever installed this must have had a load calculation of 600 or more or figured that if the last meter were ever used it could go over 600.

It's been a while but when I used to do modular meter equipment like that it ran 400, 800, 1,200 etc. no 600 tap boxes.

You might use a 800 amp tap box with 400 amp rated meter stacks out from both sides to save some money on the meter stacks.

 

[Greg1707]

Exception #3

Exception #3

I was ignorant of this exception. Just curious, would this exception apply to the split bus panels ?


"Exception No.3: Two to six circuit breakers or sets of fuses shall be permitted as the overcurrent device to provide the overload protection. The sum of the ratings of the circuit breakers or fuses shall be permitted to exceed the ampacity of the service conductors, provided the calculated load does not exceed the ampacity of the service conductors."

 

[kwired]

If you bring feeders into this it just confuses the issue, we are talking about service conductors and the rules are different.

I was ignorant of this exception. Just curious, would this exception apply to the split bus panels ?


"Exception No.3: Two to six circuit breakers or sets of fuses shall be permitted as the overcurrent device to provide the overload protection. The sum of the ratings of the circuit breakers or fuses shall be permitted to exceed the ampacity of the service conductors, provided the calculated load does not exceed the ampacity of the service conductors."

Please tell us what section that exception is part of and which code year. I looked a little in 2014 where I thought it may be from yet don't find it so far. Knowing what section this a part of helps answer your question as it only is exception to the main text it is following. There may be more then one section with similar exception sometimes though.

 

[iwire]

230.90(A)

 

[kwired]

230.90(A)

I thought I should be looking in 230, but was focusing too much on part VI instead of part VII, since I didn't find it there started to think maybe he found it in 225 or even 408, but didn't find it in those locations either.

Now I just have to put that together with the rest of his question as I'm still not quite certain I fully understand what he is asking.

But here is my shot at answering it - the split bus panel (assuming you are talking the old panels that used to have a space for up to six mains and then a "lighting section" supplied by one of those mains) I would think applies, what you essentially have is the mains section is it's own panel in a way and can have up to six main breakers installed. You can kind of forget the "lighting section" even exists for a little bit here because it is protected by an individual main in the mains section and has nothing to do with this conversation.

Of course these panels are prohibited now by 408.36 exception 1, but there are still some out there that were code compliant when they were installed. I guess it is up to AHJ's on whether they are grandfathered, and when they must be changed out, when dealing with one that once was code compliant.