30 — ElectriCalc LT
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. Am-
bient temperature is 50°C. What is the
derated wire size required if eight cur-
rent-carrying THHN wires were installed
in the raceway?
Steps Keystrokes Display
Reset calculator
[Set] [x]
0.
Set to 1-phase
[Set] 1
1 PH
Set to 90°C
[Set] 9
1Ø 90 Cu 1 PH
Toggle to alum.
[CU/AL]
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
Û &
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
Û &