Minimum Wire Size - Motors

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janderson

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Is there a minimum wire size (i.e. 16 AWG or 18AWG) that can be used as a feed to a motor in an industrial application?
 
janderson said:
Is there a minimum wire size (i.e. 16 AWG or 18AWG) that can be used as a feed to a motor in an industrial application?
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The smallest BC cond listed in the NEC is a 18 GA cu.
see 240.4(D)

This new material to the 08 was driven by NFPA 79 the proposal stated that 18 and 16 ga is used in industrial mach for branch circuits to eq. (Not the exact wording).

some one may have it on disk.
 
cpal said:
The smallest BC cond listed in the NEC is a 18 GA cu.
see 240.4(D)

This new material to the 08 was driven by NFPA 79 the proposal stated that 18 and 16 ga is used in industrial mach for branch circuits to eq. (Not the exact wording).

some one may have it on disk.
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Ask and you shall receive.

240.4 Protection of Conductors.

(D) Small Conductors. Unless specifically permitted in 240.4(E) or (G), the overcurrent protection shall not exceed that required by (D)(1) through (D)(7) after any correction factors for ambient temperature and number of conductors have been applied.

(1) 18 AWG Copper. 7 amperes, provided all the following conditions are met:

(1) Continuous loads do not exceed 5.6 amperes.

(2) Overcurrent protection is provided by one of the following:

a. Branch-circuit-rated circuit breakers listed and marked for use with 18 AWG copper wire

b. Branch-circuit-rated fuses listed and marked for use with 18 AWG copper wire

c. Class CC, Class J, or Class T fuses


(2) 16 AWG Copper. 10 amperes, provided all the following conditions are met:

(1) Continuous loads do not exceed 8 amperes.

(2) Overcurrent protection is provided by one of the following:

a. Branch-circuit-rated circuit breakers listed and marked for use with 16 AWG copper wire

b. Branch-circuit-rated fuses listed and marked for use with 16 AWG copper wire

c. Class CC, Class J, or Class T fuses


(3) 14 AWG Copper. 15 amperes


(4) 12 AWG Aluminum and Copper-Clad Aluminum. 15 amperes


(5) 12 AWG Copper. 20 amperes


(6) 10 AWG Aluminum and Copper-Clad Aluminum. 25 amperes


(7) 10 AWG Copper. 30 amperes
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Going back to what I thought prior to the "motor and industrial" and go with 310.5 chart.
 
Need clarification from the OP. Having a hard time imagining the need for smaller than #14. #14 MTW is the standard control wire in a lot of places, and, can be used for motors if it meets al the requirements of the NEC.
 
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