26401 Load Calculations - Feeders and Services Exam with || || || || || || || || ||
correct detailed solutions || ||
Load calculated at 2 circuit 1500VA. - ✔✔Small Appliance Ciruit
|| || || || || || || || ||
Voltage drop formula 1 || || ||
VD = (2*L*R*I)/1,000 - ✔✔VD = voltage drop (in volts)
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L = load center or total length in feet
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R = conductor resistance per NEC Chapter 9, Table 8
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I = current
|| ||
The number 1,000 represents 1,000' or less of conductor.
|| || || || || || || ||
Show window loads should be calculated at _____ per linear foot of show window. -
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✔✔200VA
What is the minimum demand required for the portion of a feeder that supplies 30' of show
|| || || || || || || || || || || || || || || || ||
windows?
6,000 VA ||
5,400 VA ||
3,000 VA ||
2,700 VA - ✔✔ft x va = va || || || || || || ||
30ft x 200VA = 6,000VA|| || || ||
NEC 220.14(C)(2) ||
At 200 Volt-amperes per linear 300 mm (1 ft) of show window
|| || || || || || || || || || ||
Voltage drop formula 2 || || ||
, VD = (2*L*K*I)/CM - ✔✔VD = voltage drop
|| || || || || || ||
L = load center or total length in feet
|| || || || || || || ||
K= constant (12.9 for copper conductors; 21.2 for aluminum conductors)
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I = current
|| ||
CM= area of the conductor in circular mils (from NEC Chapter 9, Table 8)
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Feeder conductor size is adjusted when? || || || || ||
The load supplied is a continuous-duty load.
|| || || || || ||
More than three current-carrying conductors are in a raceway.
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The ambient temperature surrounding conductors exceeds temperature ratings.
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Voltage drop exceeds 3% for feeders or 5% for the combination of the feeder and branch
|| || || || || || || || || || || || || || || ||
circuit.
All of the above - ✔✔All of those above
|| || || || || || || ||
In calculating feeder-circuit conductors, if noncontinuous loads equal 450 amperes and
|| || || || || || || || || || ||
continuous loads equal 550 amperes, what is the total calculated feeder load that the
|| || || || || || || || || || || || || ||
conductors must handle? || ||
A. 1137.50 amperes
|| ||
B. 1100 amperes
|| ||
C. 950 amperes
|| ||
D. 1317.50 amperes - ✔✔In order to calculate the total feeder load, you must add 100% of
|| || || || || || || || || || || || || || || || ||
noncontinuous loads to 125% of continuous loads. || || || || || ||
450 + (1.25 × 550) = 1137.50 amperes
|| || || || || || ||
correct detailed solutions || ||
Load calculated at 2 circuit 1500VA. - ✔✔Small Appliance Ciruit
|| || || || || || || || ||
Voltage drop formula 1 || || ||
VD = (2*L*R*I)/1,000 - ✔✔VD = voltage drop (in volts)
|| || || || || || || || ||
L = load center or total length in feet
|| || || || || || || ||
R = conductor resistance per NEC Chapter 9, Table 8
|| || || || || || || || ||
I = current
|| ||
The number 1,000 represents 1,000' or less of conductor.
|| || || || || || || ||
Show window loads should be calculated at _____ per linear foot of show window. -
|| || || || || || || || || || || || || || ||
✔✔200VA
What is the minimum demand required for the portion of a feeder that supplies 30' of show
|| || || || || || || || || || || || || || || || ||
windows?
6,000 VA ||
5,400 VA ||
3,000 VA ||
2,700 VA - ✔✔ft x va = va || || || || || || ||
30ft x 200VA = 6,000VA|| || || ||
NEC 220.14(C)(2) ||
At 200 Volt-amperes per linear 300 mm (1 ft) of show window
|| || || || || || || || || || ||
Voltage drop formula 2 || || ||
, VD = (2*L*K*I)/CM - ✔✔VD = voltage drop
|| || || || || || ||
L = load center or total length in feet
|| || || || || || || ||
K= constant (12.9 for copper conductors; 21.2 for aluminum conductors)
|| || || || || || || || ||
I = current
|| ||
CM= area of the conductor in circular mils (from NEC Chapter 9, Table 8)
|| || || || || || || || || || || || ||
Feeder conductor size is adjusted when? || || || || ||
The load supplied is a continuous-duty load.
|| || || || || ||
More than three current-carrying conductors are in a raceway.
|| || || || || || || ||
The ambient temperature surrounding conductors exceeds temperature ratings.
|| || || || || || ||
Voltage drop exceeds 3% for feeders or 5% for the combination of the feeder and branch
|| || || || || || || || || || || || || || || ||
circuit.
All of the above - ✔✔All of those above
|| || || || || || || ||
In calculating feeder-circuit conductors, if noncontinuous loads equal 450 amperes and
|| || || || || || || || || || ||
continuous loads equal 550 amperes, what is the total calculated feeder load that the
|| || || || || || || || || || || || || ||
conductors must handle? || ||
A. 1137.50 amperes
|| ||
B. 1100 amperes
|| ||
C. 950 amperes
|| ||
D. 1317.50 amperes - ✔✔In order to calculate the total feeder load, you must add 100% of
|| || || || || || || || || || || || || || || || ||
noncontinuous loads to 125% of continuous loads. || || || || || ||
450 + (1.25 × 550) = 1137.50 amperes
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