Raceway and Box Calculations Flashcards
Primary references in the NEC for determining raceway size and conduit fill
Chapter 9 and Annex C
Reference for when multiple conductors of the same size will be installed in a raceway
Annex C
Reference for calculating raceway size based on different wires
Chapter 9
Fill percentage of a raceway when one conductor is installed
53%
Fill percentage of a raceway when two conductors are installed
31%
Fill percentage of a raceway when three or more conductors are installed
40%
Fill percentage of a nipple (>24”) long when conductors are installed
60%
Wire jamming can occur when the ration of wire size to open space in a raceway is
2.80 and 3.20
The maximum number of wires allowed into a metal wireway is limited to ____ % of the _____
20% of the cross sectional area
Table for sizing boxes with wire sizes 6awg - 18awg
314.16(A)
Table for determing volume required for wire sizes 6awg - 18awg
314.16(B)
For box fill calculations, each conductor that is spliced is counted as
One
For box fill calculations, each conductor that terminates is counted as
One
For box fill calculations, each conductor that passes through the box without a 12” loop is counted as
One
For box fill calculations, each conductor that passes through the box with a 12” loop is counted as
Two