Box and Conduit Fill Calculations · 2020-02-28 · without outer covering and 4 -14 AWG RHH Cu Conductors with outer covering ? Table 5 – Cross-Sectional Area of Individual Conductors

Copyright 1999-2019 Dan Dudley

Box & conduit Fill Calculations



Box andConduit FillCalculations













Conductor Counts for other than wire

CableClamps

FixtureStud

Hickey

NM 12-2 W/GRD

Fixture Stud = 1 ConductorHickey = 1 ConductorCable Clamps (2) = 1 ConductorTotal Conductor Count = 3 Conductors



Terminate in the box

Count 6 total conductorsAll ConductorsTerminate in the box

Through Box = 2Terminate in box = 4Total count = 6

Though the box



Factory installed clamps8-12’s & 1 clamp = 9

Factory or fieldinstalled clamps

#12 AWG Conductors #12 AWG Conductors



EGC

EGC = Equipment Grounding ConductorIEGC = Insolated Equipment Grounding Conductor

BJ = Bonding Jumper

BJ

IEGC

EGC = 1IEGC = 2BJ = 0Total = 2

To Receptacle



Octagonal / 4/0 Box

2 - #8 AWG2 - #12 AWG

2 - #12 AWG2 - #8 @3.00 Cu = 6 Cu inFix Stud/Hickey @3.00 Cu in = 3 Cu in4 - #12 @2.25 Cu in = 9 Cu inTotal = 18 Cu in



#14 BareEGC

#8 AWG

#12 AWG

#18 AWG fixture wire

#10 AWG

#18 = 1.5 cu in x 2 = 3.00 cu in#14 = 2.0 cu in x 1 = 2.00 cu in#12 = 2.25 cu in x 4 = 9.00 cu in#10 = 2.50 cu in x 2 = 5.00 cu in#8 = 3.00 cu in x 2 = 6.00 cu inFix Stud/Hickey = #8 = 3.00 cu in = 3.00 cu inTotal Box volume required = 28.00 cu in



Bad Planning





314.16(b)(1) ExceptionCanopy Cover

EGC

Terminations inCanopy Cover

To FanTo Fixture

4 - Smaller than #14 Fixture wires

Dome Canopy

Do not count for Box Fill Calculations



Counting with a device2 - #8 AWG

2 - #12 AWG

2 - #12 AWG

2 - #8 @3.00 cu in = 6 cu in4 - #12 @2.25 cu in = 9 cu inYoke/Device @2.25 cu in = 4.5 cu inTotal Volume Required = 19.5 cu in

Largest conductor allowed = #10NEC 110.14(A)



Total conductors = 11 - #12 AWG4 X 2 1/8 “ (Deep) Box Required



Total Conductors = 8 #10 AWGBox Required = 4 X 2 1/8” (Deep) Box





“U” pull Junction Box Calculation













Conduit FillCalculations



RMC and IMC With Threaded Couplings

NEC 344.30



Rigid PVC

NEC 352.30



Major Fraction Change

Chapter 9, Table 1, Note 7





Table 5 – Cross-Sectional Area of Individual Conductors2/0 AWG THW Cu = .2624 X 3 = .78724/0 AWG THHN Cu = .3237 X 4 = 1.2984Total Square Inches for Conductors = 2.0820

Table 4 – 40% fill column for “Over 2 wires”.2.0820 Sq.In. Requires a 2 ½ inch EMT Conduit40% fill for 2 ½ inch EMT = 2.343 Sq. In.

Answer = 2 ½ Inch EMT

What size EMT is needed for 3 - 2/0 AWG THW Cuconductors and 4 - 4/0 AWG THHN Cu conductors ?



What size IMC is required for 6 - 12 AWG RHH Cu conductorswithout outer covering and 4 -14 AWG RHH Cu Conductors

with outer covering ?

Table 5 – Cross-Sectional Area of Individual Conductors14 AWG RHH Cu With Outer Covering = .0293 X 4 = .117212 AWG RHH Cu Without Outer Covering = .0260 X 6 = .1560Total Square Inches for Conductors = .2732

Table 4 – 40% fill column for “Over 2 wires”..2732 Sq.In. Requires a 1 inch IMC Conduit40% fill for 1 inch IMC = .384 Sq. In.

Answer = 1 Inch IMC





Box & Conduit Fill Exam

30 Minutes

Documents

Box and Conduit Fill Calculations · 2020-02-28 · without outer covering and 4 -14 AWG RHH Cu Conductors with outer covering ? Table 5 – Cross-Sectional Area of Individual Conductors