12 —
e
lectri
c
alc
®
P
ro
(cont’d)
Wire resistance (Wire res) —
Displays the
actual Resistance per 1,000 Feet of the Wire Size
in
based on NEC Chapter 9, Table 8.
Grounding Conductor Keys
Ground —
Used to find the Grounding electrode
conductor size for AC systems based on NEC
Table 250.66 and an entered or calculated
service-entrance conductor (largest size). Only
actual Wire Sizes are considered valid entries.
♦ First Press
Calculates the copper Grounding electrode
conductor size if you have entered a valid
Wire Size.
♦ Second Press
Displays the aluminum Grounding electrode
conductor size.
♦ Third Press
Displays the Circular Mil area used to calculate
the Grounding electrode conductor size.
♦ Fourth Press
Displays the NEC table referenced for
the calculation.
equipment Ground (eqGrnd) —
This function
uses NEC Table 250.122 to calculate the
minimum equipment Grounding conductor size,
given an entered Amperage rating or setting for
an over-current device up line.
Note:
This function deviates from the NEC Table
250.122 in that 1250 MCM AL is used instead of
1200 as specified in NEC Table 250.122.
♦ First Press
Displays the copper Grounding conductor size
for the entered Amp rating.
