What percentage of panel rating?

[AZsparky]

What is the latest NEC on what percentage of a 200 amp rated main breaker Residential panel (Entire Service) that you can use? Load Calcs come out to 167 amps. I thought it was 80%. Installing a Tesla 240 volt electric car charge station that is capable of 80 amps continuos load, but it has dip switches that allow it to be modified to 80, 64, 40, 32, 24, 16 and 12. I'm figuring only on the 40 amp setting for my load calcs at 167 amps, as the 80 amp setting would put it well over the service rating.

Who the hell installs a 200 amp service for a 4,500 s.f. residence to begin with?

 

[Smart $]

200A non-continuous.
160A continuous.
Somewhere in between for combination loads (100% non-continuous plus 125% continuous).

IIRC, EVC's are to be considered continuous loads.

 

[kwired]

Service/feeder calculations from art 220 already account for continuous loads as well as demand factors, if your art 220 calculation is 200 amps - you can use a 200 amp conductor and a 200 amp overcurrent device, if your art 220 calculation is 201 amps - next standard sized overcurrent device is 225 amps - but you still only need 201 ampacity for the conductor.

 

[Smart $]

Service/feeder calculations from art 220 already account for continuous loads as well as demand factors, if your art 220 calculation is 200 amps - you can use a 200 amp conductor and a 200 amp overcurrent device, if your art 220 calculation is 201 amps - next standard sized overcurrent device is 225 amps - but you still only need 201 ampacity for the conductor.

Article 220 calculations do not account for continuous loads.

 

[kwired]

Article 220 calculations do not account for continuous loads.

220 doesn't require any adjustments because you have a continuous load, therefore continuous loads are already accounted for as is. Or even if I/you/we did miss something, your final result after running through art 220 is still your minimum ampacity needed with no further adjustment to the load values. Though the conductors may need further adjustments depending on installation conditions.

 

[Smart $]

220 doesn't require any adjustments because you have a continuous load, therefore continuous loads are already accounted for as is. Or even if I/you/we did miss something, your final result after running through art 220 is still your minimum ampacity needed with no further adjustment to the load values. Though the conductors may need further adjustments depending on installation conditions.

Articles 210, 215, 230 in a roundabout way, all require factoring continuous loads by 125% to determine minimum ungrounded wire size and ocpd rating... unless you are using 100% rated equipment. Other than the latter, I do not know of any instance where you can have a 200A panel with 200A of continuous load.

 

[kwired]

Articles 210, 215, 230 in a roundabout way, all require factoring continuous loads by 125% to determine minimum ungrounded wire size and ocpd rating... unless you are using 100% rated equipment. Other than the latter, I do not know of any instance where you can have a 200A panel with 200A of continuous load.

So we go through art 220 and find a load level for general lighting based on square footage and type of occupancy and maybe even apply demand factors where allowed - are you saying we then need to multiply that result by 125% if it is continuous load? I always understood art 220 calculations to be a final result and we do not need to add 125% for continuous loads - you make no adjustment to the result, if you determine the load for a feeder to be 146 amps via methods in art 220 then you need a 146 amp conductor and next higher standard overcurrent device of 150 amps as a minimum to supply that load.

 

[Smart $]

So we go through art 220 and find a load level for general lighting based on square footage and type of occupancy and maybe even apply demand factors where allowed - are you saying we then need to multiply that result by 125% if it is continuous load? I always understood art 220 calculations to be a final result and we do not need to add 125% for continuous loads - you make no adjustment to the result, if you determine the load for a feeder to be 146 amps via methods in art 220 then you need a 146 amp conductor and next higher standard overcurrent device of 150 amps as a minimum to supply that load.

To determine wire size, ocpd rating, panel rating, disconnecting means rating.... yes... but you also need the total value without 125% continuous factoring.

See Examples D3. Noncontinuous and continuous loads are tracked separately through the calculation. Continuous load portion is then factored 125% in the minimum size feeder (or service) overcurrent protection section and note the section references.

 

[kwired]

To determine wire size, ocpd rating, panel rating, disconnecting means rating.... yes... but you also need the total value without 125% continuous factoring.

See Examples D3. Noncontinuous and continuous loads are tracked separately through the calculation. Continuous load portion is then factored 125% in the minimum size feeder (or service) overcurrent protection section and note the section references.

I see, thanks.