Electrical Level 3 Module 1 Load Calculations and Branch Feeder Circuits
What is the required circuit ampacity for a noncontinuous, three-phase load of 6kW at 208V?
16.65A
What is the total ampacity for a 120V branch circuit consisting of four duplex receptacles rated noncontinuous duty and six duplex receptacles rated continuous duty?
17.25A
What is the load center distance for a 208V, four-wire, three-phase branch circuit with fixed noncontinuous loads from the source of 60A at 45', 40A at 60', 30A at 75', and 25A at 100'
63.55'
What is the required circuit ampacity of a noncontinuous, single-phase load of 8.5kW at 277V?
30.69A
For resistance welders, the rating for the overcurrent protection device should not exceed what percentage of the primary current rating of the welder?
300%
What is the demand load for one household range with a nameplate rating of 11.75kW, 240V, 1Ø?
8kW
What is the total load required by the NEC® for two appliance branch circuits plus a laundry branch circuit?
4,500VA
The allowable ampacity for eleven No. 12 THHN copper conductors in a cable must be adjusted by
50%
What is the motor full-load current for a motor with a nameplate rating of 50hp, 460V, 3Ø?
65A
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
What is the load center length for a branch circuit with noncontinuous loads of 20A at 60' and 50A at 125'?
106.43'
Show window lighting is calculated at 200VA per linear foot plus
125%
What is the load for 55' of show window using the linear foot method?
13,750VA
What is the lighting load on a 120V circuit for six 100W incandescent lights and four fluorescent fixtures with a ballast rating of 1.5A, all operating continuously for 8 hours per day? 13.75A
13.75A
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%
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?
3
For a given load and length, the branch circuit voltage drop should not exceed
3%
What is the current-carrying capacity for No. 6 THWN aluminum conductors in conduit run through an ambient temperature of 38°C?
44 Amps
What is the voltage drop for a 120V, single-phase, two-wire branch circuit, 100' long, using copper conductors of 6,530 circular mils with a noncontinuous load of 13A? 5.14V
5.14V
Continuous loads are calculated at what percentage of the maximum current rating of the overcurrent device?
80%
What is the load center length for a branch circuit consisting of noncontinuous loads of 125A at 80', 75A at 110', and 50A at 100'?
93'
When connected to 15A or 20A multi-outlet general-purpose branch circuits, which of the following shall not exceed 50% of the branch circuit ampere rating?
Fastened-in-place utilization equipment
What size copper conductor would be required for a 240V, 1Ø circuit supplying a noncontinuous load of 27.5A at a distance of 145', and a maximum voltage drop of 3%?
No. 10
Conductors must be derated when installed in conduit
on or above rooftops
