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
For box fill calculations, each conductor that originates in the box, and terminates in the box is counted as
Zero
For box fill calculations, one or more clamps counts as ____ and is sized based on the ____
One
Largest conductor entering the box
For box fill calculations, each luminaire hickey counts as ____ and is sized based on the ____
One
Largest conductor entering the box
For box fill calculations, each yoke in the boxx counts as ___ and is based on the ___
Two
Largest conductor terminating on the device
For box fill calculations, each multigang yoke count as ___ per gang, and is based on the ___
Two
Largest conductor terminating on the device
For box fill calculations, all EGC’s entering a box count as ___ and is based on the ___
One
Largest EGC entering the box
For box fill calculations, and isolated EGC counts as ___
One additional
For box fill calculations involving wire sizes 4awg and larger, Table ____ must be used
314.28
For straight pulls through a junction box, the size of the junction box must not be less than ___ times the size of the largest raceway entering the box
8
For angle pulls through a junction box, the size of the junction box must not be less than ___ times the size of the largest raceway plus the sum of the trade sizes of the raceway(s) on the ___
6
Same row/side
For U pulls through a junction box, the size of the junction box must not be less than ___ times the size of the largest raceway plus the sum of the trade sizes of the raceway(s) on the ___
6
Same row/side
For splices pulls in a junction box, the size of the junction box must not be less than ___ times the size of the largest raceway plus the sum of the trade sizes of the raceway(s) on the ___
6
Same row/side