Calculations and Branch Feeder Circuits
According to the NEC®, the ampacity of branch circuit conductors must be derated
when there are more than how many current-carrying conductors in a raceway? - ANS
- 3
Air conditioning overcurrent protective devices can never exceed what percentage of
the motor-rated load current or the branch circuit selection current (whichever is
greater)? - ANS - 225%
Conductors must be derated when installed in conduit - ANS - on or above rooftops
Continuous loads are calculated at what percentage of the maximum current rating of
the overcurrent device? - ANS - 80%
For a given load and length, the branch circuit voltage drop should not exceed - ANS -
3%
For resistance welders, the rating for the overcurrent protection device should not
exceed what percentage of the primary current rating of the welder? - ANS - 300%
Show window lighting is calculated at 200VA per linear foot plus - ANS - 125%
The allowable ampacity for eleven No. 12 THHN copper conductors in a cable must be
adjusted by - ANS - 50%
The load for 10' of multi-outlet assembly used to supply several loads simultaneously is
- ANS - 1,800VA
The maximum size dual-element fuse for a 40hp, 3Ø, 460V motor with a Design Letter
D is - ANS - 100A
What is the current-carrying capacity for No. 6 THWN aluminum conductors in conduit
run through an ambient temperature of 38°C? - ANS - 44 Amps