200 A service / 3 apartments

[richwaskowitz]

This is realated to but separate from another posting in the "grounding" section.

An existing installation has a fairly new 200 amp service (4/0 Al) to a three meter base. Each meter feeds a fuse box with 2/2/4/ Al. The customer wants to replace the fuse panels with breakers. The load calculations do not indicate a load anywhere near the 200 amp service. Does installing 3 100 amp main breaker panels in this application constitute a violation? If so, please cite the rule. I have been doing this and have seen this done for years and never questioned it until I read a similar post about a 100 and a 200 amp panel today.

 

[charlie b]

Re: 200 A service / 3 apartments

If your load calculation shows less than a 200 amp service load, then you can do what you suggest. Having a 100 amp main breaker panel is no different from having a 100 amp fuse panel, so the substitution is not an issue either.

 

[jeff43222]

Re: 200 A service / 3 apartments

Even if the load calculation shows everything to be within bounds, theoretically each owner of those 100A panels could run them simultaneously at close to their max without tripping their breakers. Under this admittedly unlikely scenario, what kind of protection would there be for the 4/0 Al between the meters and the service point?

 

[iwire]

Re: 200 A service / 3 apartments

Originally posted by jeff43222:
Even if the load calculation shows everything to be within bounds, theoretically each owner of those 100A panels could run them simultaneously at close to their max without tripping their breakers. Under this admittedly unlikely scenario, what kind of protection would there be for the 4/0 Al between the meters and the service point?

Not much, but it is specifically allowed by 230.90(A)Exception No. 3

 

[richwaskowitz]

Re: 200 A service / 3 apartments

Thank you. It is clear now.