ELECTRICAL LEVEL 3 MODULE 1 LOAD
CALCULATIONS AND BRANCH FEEDER
CIRCUITS (Latest 2026) Questions and
Answers (Verified Answers) | Guaranteed
Success | 100% Correct
• maximum load that may be supplied by 20a, 120v circuit? -✓✓20a x
120v = 2400va
• maximum load that may be supplied by 20a, 3 wire, 120/240v circuit?
-✓✓20a x 240v = 4800va
• maximum load that may be supplied by 20a, 208v 3 phase circuit? -
✓✓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? -✓✓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? -✓✓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? -✓✓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? -✓✓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? -✓✓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? -
✓✓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? -✓✓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? -✓✓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? -✓✓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? -✓✓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
• size thhn recommended for a non-contiuous load with 130' of single
phase, 23a, 240v? -✓✓vd = 2 x L x r x i / circular mils
vd = 2 x 130' x 12.9 x 23a / 10380 no.10 wire
vd = 7.43v / 240 = 0.031
0.031 x 100 =3.10%
need to size up to no.8 wire
CALCULATIONS AND BRANCH FEEDER
CIRCUITS (Latest 2026) Questions and
Answers (Verified Answers) | Guaranteed
Success | 100% Correct
• maximum load that may be supplied by 20a, 120v circuit? -✓✓20a x
120v = 2400va
• maximum load that may be supplied by 20a, 3 wire, 120/240v circuit?
-✓✓20a x 240v = 4800va
• maximum load that may be supplied by 20a, 208v 3 phase circuit? -
✓✓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? -✓✓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? -✓✓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? -✓✓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? -✓✓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? -✓✓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? -
✓✓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? -✓✓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? -✓✓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? -✓✓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? -✓✓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
• size thhn recommended for a non-contiuous load with 130' of single
phase, 23a, 240v? -✓✓vd = 2 x L x r x i / circular mils
vd = 2 x 130' x 12.9 x 23a / 10380 no.10 wire
vd = 7.43v / 240 = 0.031
0.031 x 100 =3.10%
need to size up to no.8 wire
