800a Mdp

[ces]

Don,
Excellent point. Trying to squeeze every last amp out of a conductor is typically something i do only when a contractor is my client. But not every building owner looks that far ahead either, if they did would we have solar panels on most buildings?

Gary

 

[don_resqcapt19]

Gary,

if they did would we have solar panels on most buildings?

I am not sure that solar panels are really cost effective at this point, but on a circuit that serves equipment that runs most of the time, the payback time for upsizing the conductor a size or 2 over code minimum is often 12 to 18 months.
Don

 

[jameshot]

Where is this 800 amp service being metered from ? Where do the conduits have to go for the feed ? You said 200 plus feet. up the power pole to the building underground? If thats the case how come you just don't mount a large ct outdoor cabinet /tap box and then feed the 800amp mdp have the owner pay the cost of the wire to the power /utility company to feed the building.

 

[wirenut1980]

OK I have to ask what may be a dumb question but what would the auctual load have to do with it if it has a 800A main disconect? I thought it would just be sized to the 800A. BTW the VD is 6.27% using 300MCM and the max length is 250.18'. So it seems that 3 raceways with 4-300MCM should deliver the 800A needed. The auctual load for the building according to the prints is about 350A. Another thing I found funny on the prints it that a 125A 42ckts panel has been specified even though the 4 breakers in it are at 80% capicity. Why would someone spec a panel that has 42ckts at 125A when its at max capicity with only 4ckts in it. Seems strange to me because in my area it had to be custom ordered. They had the same specs in a 32ckt panel.

It could be a case where the calculated load is, say 750 amps, so you round up to 800 Amps on the main disconnect. Well, 230.23 says that service conductors must be sized to carry the calculated load, and not necessarily sized for the main disconnect in this case. So you can size your service conductors to the 750 amps, and not to the 800 amps.


Is that 350 amps actual load calculated per Article 220? If you don't know the answer to that, it might be worthwhile to check them. Also, what type of restaurant is it? Fast food, a larger sit down place?

For what it's worth, I see a lot of 600 Amp main disconnects for your typical fast food joints.