Service Disconnect Sizing

[Aistobasbistoc9]

I've got 6 panels each serving a different tenant suite being fed from a single bussed gutter. There is a main fused 800A disconnect for the bussed gutter. Each panel load is calculated per NEC with continuous, lighting, etc. loads at 1.25 of the kVA, and non continuous, receptacle, etc. loads (receptacles under 10kVA to keep this example simple)at 1.00 of the kVA. Each panel load is calculated individually and then for the load summary are added together for a total of 780A. Does the fused disconnect need to be sized at 1.25*780 amps and upsized to a 1000A (closest to the resulting 975 amps), or will the 800A fused disconnect suffice?

Please provide with all NEC reference where possible and I appreciate all the help.


Thank you

 

[JoeStillman]

If the downstream feeders were calculated at 100% non-continuous plus 125% of continuous, then there is no reason to multiply the total by 125%. The 100%/125% rule is found at 215.(A)(1)(a).

You can also apply the 10 kVA + 50% receptacle diversity if the total receptacle load on the main feeder is over 10 kVA, but that won't work if you've already applied it on any of the downstream feeders. That would be double dipping on any receptacles you've already diversified.

 

[Aistobasbistoc9]

If the downstream feeders were calculated at 100% non-continuous plus 125% of continuous, then there is no reason to multiply the total by 125%. The 100%/125% rule is found at 215.(A)(1)(a).

You can also apply the 10 kVA + 50% receptacle diversity if the total receptacle load on the main feeder is over 10 kVA, but that won't work if you've already applied it on any of the downstream feeders. That would be double dipping on any receptacles you've already diversified.

Thank you