42 — ElectriCalc Pro
IMPORTANT NOTE ON
VOLTAGE DROP CALCULATIONS
The
ElectriCalc Pro
calculates Voltage
drop and wire size using DC resistance as
defined by the 2008 NEC. To find the
Voltage drop for a
specific
wire size, you
must
first enter Amps and the one-way
wire Length
(and other required variables),
entering the specific wire size
last
.
Otherwise, for your safety the calculator
will recalculate the wire sizes based on
the NEC Ampacity Tables and maximum
allowable Voltage drop.
Finding Single-Phase Voltage Drop
You are installing 175 Feet of 75°C, #8 THW
branch circuit copper conductors to supply
an 11A load on a 208V 1Ø system. What is
the source Voltage drop at the load?
Steps
Keystrokes
Display
Clear calculator
o o
0.
Set to 1-phase
S 1
1 PH
Set to 75°C
S 7
1Ø 75 Cu 1 PH
Enter Amps
1 1 A
AMPS 11.
Enter Volts
2 0 8 U
VOLT 208.
Enter Length
1 7 5 l
FEET 175.
Enter wire size*
8 w
AWG 8 CU
WIRE SIZE
Solve volt. drop
v
DROP 3.0 V
Solve % v.drop
v
DROP 1.4 V %
* Wire size can also be entered in
Circular Mils (e.g.,
1 6 5 1 0 w
enters 16,510 CMILs and displays 8 AWG
wire size).
