Control Circuit 208V--Wire Gauge

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fifty60

Senior Member
Location
USA
Is it ok to use 16AWG on a contactor coil that is 208VAC? Or, will I have to use 14AWG even though it is just a contactor coil?
 

augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
I know of nothing that prohibits #16. 430.72 & 725.49 plus other sections address the situation.
 

augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
You can certainly send 208v down a #16 assuming it is fused properly and the insulation is rated for the highest voltage expected in the raceway or enclosure.

I was hesitant to make that statement as it may be dependent on the Code cycle the reader is using. 310.5 in the '08 Code has a minimum of #14 unless otherwise allowed.
 

kwired

Electron manager
Location
NE Nebraska
I was hesitant to make that statement as it may be dependent on the Code cycle the reader is using. 310.5 in the '08 Code has a minimum of #14 unless otherwise allowed.
Been some rearrangement in that area of NEC and I don't have 08 in front of me, but I'm sure it was about same content as in 2014 - 310.106, which is general conductor information - for a control circuit there are other sections like you mentioned that allow for smaller conductors and with that can be differences in permitted overcurrent protection as well.
 

templdl

Senior Member
Location
Wisconsin
Why are you asking the question? Is this a question concerning saving money? The cost of #14 MTM for a small job is insignificantly more than using #16. Often times projects are speced with #14 minimum even though smaller would be allowed by the code.
Please refer to NFPA 79 Art 15 Conductors, and 15.3 Conductor Sizing. a) Power Circuits, #14, b) Lighting and control circuits on the machine and in raceways, #16, c) Control circuits with control enclosures or operating stationed #18, and d) Electronic PLCs I/O #24 and #26.
Of course these are minimums as ampavcities are based upon table 9 for single conductor characteristics.
I you are asking the question please get a copy of NFPA 79 for your reference to have on file.
 
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fifty60

Senior Member
Location
USA
Thanks everyone, this was very helpful. I will look at all of the provided references. It is for wire that is already installed, trying to choose between replacing or leaving it as is. The answer is clear now, I appreciate the help.
 

augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
Been some rearrangement in that area of NEC and I don't have 08 in front of me, but I'm sure it was about same content as in 2014 - 310.106, which is general conductor information - for a control circuit there are other sections like you mentioned that allow for smaller conductors and with that can be differences in permitted overcurrent protection as well.

Very Good ! Your comment prompted me to complete my research. 310.5 ('08) is 310.106 (''11)
and #14 is the minimum unless otherwise permitted in the Code.
I will stand by my Post 4.
 
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