ELECTRICAL LEVEL 3 MODULE 1 LOAD
CALCULATIONS AND BRANCH FEEDER
CIRCUITS PRACTICE TEST 2026 QUESTIONS
WITH CORRECT SOLUTIONS GRADED A+
◉ maximum load that may be supplied by 20a, 3 wire, 120/240v
circuit? Answer: 20a x 240v = 4800va
◉ maximum load that may be supplied by 20a, 208v 3 phase circuit?
Answer: 20a x 208v x 1.732 = 7205.12va
◉ minimum size circuit breaker required for 9 florescent ballast
rated at 1.5a at 120v, as a continuous load? Answer: determine
branch circuit load
9 x 1.5a = 13.5a
determine the continuous duty load
13.5a x 1.25 = 16.88a
minimum breaker size is 20a
,◉ how many receptacle outlet devices in other than residential
occupancies can be connected to a 20a, 120v circuit? Answer:
determine branch circuit capacity
20a x 120v = 2400va
nec section 220.14.i each outlet is assigned a lad of 180va so
2400va / 180va = 13.33 or 13 receptacle outlets
◉ what is the minimum size branch circuit required to serve a 17a,
120v copy machine? Answer: nec sections 210.23a1 and b, the
rating of any one cord connected utilization equipment shall not
exceed 80% of the branch circuit rating.
30a x 0.8 = 24a so the minimum size circuit is 30a
◉ maximum lighting load connected to a 20a circuit supplying
equipment with a rating of 8.5a, 120v? Answer: 20a - 8.5a = 11.5, the
equipment load is only 50% of the circuit rating so 11.5% may be
added.
◉ minimum size branch circuit required to supply a 14.7a, 208v, 3
phase, continuous load restaurant dishwasher? Answer: 14.7 x 1.25
= 18.38a, so 20a is the minimum
,◉ derated ampacity for each of 8, no.12 thhn wire in a single
conduit? Answer: 310.15b16 ampacity is 30a
310.15b3a adjustment factor is 70%
70% or 30a = 30a x 0.7 = 21a
◉ maximum load connected on each of 6, no.2 thwn wires in a single
conduit? Answer: 310.15b16 ampacity is 115a
310.15b3a adjustment factor 80%
80% of 115a = 155a x 0.8 = 92a
◉ the ambient temp. in a room is 92f (33.3c) minimum size thhn
wire to supply equipment? Answer: 310.15b16 ampactiy is 75a
310.15b3a adjustment factor 0.96
75a x 0.96 = 72a is no.6 thhn is required
◉ minimum size wire and over current protection device required
for a 16a circuit of continuous loads, with 12 thhn in a raceway with
an ambient temp. of 105f? Answer: 210.19a1 conductors
210.20a overcurrent
, 16a x 1.25 = 20a for a continuous load
310.15b3a adjustment factor 50%
20a / 0.50 = 40a
310.15b2a ambient temp. adjustment
40a / 0.87 = 45.98a
310.15b16 no.8 thhn on a 20a ocpd
◉ will 95' of no.12, 120v, 14.5a, non-contiuous load, exceed 3%
voltage drop? Answer: chapter 9, table 8 no.12 resistance is 1.93
ohms
vd =2 x L x r x i / 1000
vd = 2 x 95' x 1.93 x 14.5a / 1000
vd = 5.32
divide by 120v to find percentage
5.32v / 120v = 0.0443
0.0443 x 100 = 4.43% so yes it will exceed the 3% allowed
CALCULATIONS AND BRANCH FEEDER
CIRCUITS PRACTICE TEST 2026 QUESTIONS
WITH CORRECT SOLUTIONS GRADED A+
◉ maximum load that may be supplied by 20a, 3 wire, 120/240v
circuit? Answer: 20a x 240v = 4800va
◉ maximum load that may be supplied by 20a, 208v 3 phase circuit?
Answer: 20a x 208v x 1.732 = 7205.12va
◉ minimum size circuit breaker required for 9 florescent ballast
rated at 1.5a at 120v, as a continuous load? Answer: determine
branch circuit load
9 x 1.5a = 13.5a
determine the continuous duty load
13.5a x 1.25 = 16.88a
minimum breaker size is 20a
,◉ how many receptacle outlet devices in other than residential
occupancies can be connected to a 20a, 120v circuit? Answer:
determine branch circuit capacity
20a x 120v = 2400va
nec section 220.14.i each outlet is assigned a lad of 180va so
2400va / 180va = 13.33 or 13 receptacle outlets
◉ what is the minimum size branch circuit required to serve a 17a,
120v copy machine? Answer: nec sections 210.23a1 and b, the
rating of any one cord connected utilization equipment shall not
exceed 80% of the branch circuit rating.
30a x 0.8 = 24a so the minimum size circuit is 30a
◉ maximum lighting load connected to a 20a circuit supplying
equipment with a rating of 8.5a, 120v? Answer: 20a - 8.5a = 11.5, the
equipment load is only 50% of the circuit rating so 11.5% may be
added.
◉ minimum size branch circuit required to supply a 14.7a, 208v, 3
phase, continuous load restaurant dishwasher? Answer: 14.7 x 1.25
= 18.38a, so 20a is the minimum
,◉ derated ampacity for each of 8, no.12 thhn wire in a single
conduit? Answer: 310.15b16 ampacity is 30a
310.15b3a adjustment factor is 70%
70% or 30a = 30a x 0.7 = 21a
◉ maximum load connected on each of 6, no.2 thwn wires in a single
conduit? Answer: 310.15b16 ampacity is 115a
310.15b3a adjustment factor 80%
80% of 115a = 155a x 0.8 = 92a
◉ the ambient temp. in a room is 92f (33.3c) minimum size thhn
wire to supply equipment? Answer: 310.15b16 ampactiy is 75a
310.15b3a adjustment factor 0.96
75a x 0.96 = 72a is no.6 thhn is required
◉ minimum size wire and over current protection device required
for a 16a circuit of continuous loads, with 12 thhn in a raceway with
an ambient temp. of 105f? Answer: 210.19a1 conductors
210.20a overcurrent
, 16a x 1.25 = 20a for a continuous load
310.15b3a adjustment factor 50%
20a / 0.50 = 40a
310.15b2a ambient temp. adjustment
40a / 0.87 = 45.98a
310.15b16 no.8 thhn on a 20a ocpd
◉ will 95' of no.12, 120v, 14.5a, non-contiuous load, exceed 3%
voltage drop? Answer: chapter 9, table 8 no.12 resistance is 1.93
ohms
vd =2 x L x r x i / 1000
vd = 2 x 95' x 1.93 x 14.5a / 1000
vd = 5.32
divide by 120v to find percentage
5.32v / 120v = 0.0443
0.0443 x 100 = 4.43% so yes it will exceed the 3% allowed
