ELECTRICAL LEVEL 3 MODULE 1 LOAD
CALCULATIONS AND BRANCH FEEDER
CIRCUITS COMPLETE DETAILED CASE
STUDY
kAccording 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? - 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)? - 225%
Conductors must be derated when installed in conduit - on or above rooftops
Continuous loads are calculated at what percentage of the maximum current rating of the overcurrent
device? - 80%
For a given load and length, the branch circuit voltage drop should not exceed - 3%
For resistance welders, the rating for the overcurrent protection device should not exceed what
percentage of the primary current rating of the welder? - 300%
Show window lighting is calculated at 200VA per linear foot plus - 125%
The allowable ampacity for eleven No. 12 THHN copper conductors in a cable must be adjusted by - 50%
The load for 10' of multi-outlet assembly used to supply several loads simultaneously is - 1,800VA
The maximum size dual-element fuse for a 40hp, 3Ø, 460V motor with a Design Letter D is - 100A
CALCULATIONS AND BRANCH FEEDER
CIRCUITS COMPLETE DETAILED CASE
STUDY
kAccording 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? - 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)? - 225%
Conductors must be derated when installed in conduit - on or above rooftops
Continuous loads are calculated at what percentage of the maximum current rating of the overcurrent
device? - 80%
For a given load and length, the branch circuit voltage drop should not exceed - 3%
For resistance welders, the rating for the overcurrent protection device should not exceed what
percentage of the primary current rating of the welder? - 300%
Show window lighting is calculated at 200VA per linear foot plus - 125%
The allowable ampacity for eleven No. 12 THHN copper conductors in a cable must be adjusted by - 50%
The load for 10' of multi-outlet assembly used to supply several loads simultaneously is - 1,800VA
The maximum size dual-element fuse for a 40hp, 3Ø, 460V motor with a Design Letter D is - 100A
