(2) 200 amp panels on 200 amp service.

[stevenj]

I'm going to disagree, what would be the difference if I ran one 200amp main panel, and 2 - 20 circuit sub panels fused at 100amps each? Why would you need a 400amp service if the calculation doesn't need it?

Ok, see what your doing here. I did something like this on my own home. My install is very close to yours. this is what i did

fist panel 200 Amps main disconnect\ transfer installed outside of home. 2nd ( sub) panel 100 amps, 3rd panel (sub) 100 amps. The main panel is just a 200 breaker with a transfer switch; that’s it nothing else. 2nd and 3rd panels are subs. 200 Amp meter service. My load cal was 180 something amps on my home. You can add breakers in the subs, but you don’t have to. i did add 100 amp dissconnects to the sub panels for many reasons. My install was approved by the AHJ, even complemented me on such nice work.

Check your load calculations. I’m sure you don’t need 400 amp service.

 

[stevenj]

I also did a home with a 200 amp main breaker\ transfer switch . 1st sub 200 amps 40 space square D panel. 2nd sub 100 amp 24 space square D panel, and a 3rd sub with 30 amp 6 space panel for the separate garage. 4 panels total. lots of underground work here in this job. this had 200 amp meter service. load cal I believe was 190 Amps.

 

[stevenj]

I'm going to disagree, what would be the difference if I ran one 200amp main panel, and 2 - 20 circuit sub panels fused at 100amps each? Why would you need a 400amp service if the calculation doesn't need it?

Ok, see what your doing here. I did something like this on my own home. My install is very close to yours. this is what i did

fist panel 200 Amps main disconnect\ transfer installed outside of home. 2nd ( sub) panel 100 amps, 3rd panel (sub) 100 amps. The main panel is just a 200 breaker with a transfer switch only that’s it nothing else. 2nd and 3rd panels are subs. 200 Amp meter service. My load cal was 180 something amps on my home. You can add breakers in the subs, but you don’t have to. My install was approved by the AHJ, even complemented me on such nice work.

Check your load calculations. I’m sure you don’t need 400 amp service.

 

[Cavie]

Load calc will need to be "connected load" clac.

 

[inspector141]

Why would he size it based on the connected load?

 

[Cavie]

Why would he size it based on the connected load?

Cause the AHJ who signed my paycheck said so. therefor, if you install in Lee County Fl you do a connected load calc. This is not correct?

 

[Jim W in Tampa]

OK i am seeing this as your main breaker is 200 amps and is 1 of the 2 breakers in this transfer switch. From the main breaker your feeding 2 ml panels. If the total calculated load for this job is 200 amps or less then why would you not be ok. If for any reason load ever got over 200 there is no danger as breaker should trip.
My own place starts with a 200 amp main 8 space panel with feed thru lugs that then feed a 40 circuit panel. This 40 in turn feeds a sub panel from a 100 amp breaker. The 8 spaces in first panel feed a shed with 20 circuits, another sub panel 16 space that handles washer ,dryer,5 ton heat pump ,2 ton window unit,4 dedicated 20 amp 120 receptacles. Also out of first i feed a 3.5 ton package straight cool with 10 kw heat. All total i have about 80 spaces for breakers and 70 are used now. Even when throwing a large party and all AC units running at night i only consume about 10 kw per hour for about 7 hours. Point is number of panels and spaces has nothing to do with actual load. 80 spaces from 2 -200 amp panels does not = 400 amps.