Sizing Service Entrance Conductors - 2014 NEC

[srbtrout]

I am studying for the code calculations portion of my WA State Residential Administrator's exam (based on 2014 NEC).

When sizing service entrance conductors for a single family dwelling using either the standard or optional methods, which value of current do I multiply by 83%?

The calculated load (27600 volt-amps divided by 240 volts = 115 Amps?

or

The service rating determined by the next standard breaker size, 125 Amps?

 

[ramsy]

The conductor is allowed to be sized 83% of the Main breaker.

..shall be permitted to have an ampacity not less than 83 percent of the (service or feeder) rating.

 

[Dennis Alwon]

Ramsy got it... If you have a 200 amp main breaker then the conductors feeding that 200 amp breaker can be sized at 166 amps (200 x .83) or larger.

 

[srbtrout]

Thank you both! ?