User’s Guide — 41
Sizing Temperature-Adjusted
Derated Wires
A circuit was built with 90°C aluminum
wire connecting a 47,650 volt-amp load
to a 240 volt, single-phase source.
Ambient temperature is 50°C. What is
the derated wire size required if eight
current-carrying THHN wires were in-
stalled in the raceway?
Steps
Keystrokes
Display
Reset calculator
[On/C]
0.
Set to 1-phase
[Set] [1]
1 PH
Set to 90°C
[Set] [9]
1Ø 90 Cu 1 PH
Toggle to alum.
[Set] [4]
1Ø 90 Al 1 PH
Enter volt-amps
47650 [VA]
47,650. VA
Enter volts
240 [Volts]
240. VOLT
Set to 50°C amb
50 [Set] [2]
AMB° 50˚ C
Find adjst wire sz. [WireSz]
300 AL
AWG WIRE SIZE
Find derated
8 [Set] [ParSz]
500 AL
wire size
D/R WIRE SIZE
NOTE: Ambient temperature should be
changed back to 30°C to avoid conflicts
in answers through out the rest of this
manual.
Reset to 30°C
30 [Set] [2]
AMB° 30˚ C
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