Low voltage communication wire

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frofro19

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VA.
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Master Electrician
Can 300 volt communication wire (8 conductor thermostat wire) be run in the same conduit as the power conductors rated at 600 volts. An example would be 18/8 thermostat wire in same conduit with #2 direct burial cable running from a ATS to a back-up generator?
 
They can as long as the voltage on any circuit does not exceed the 300 V of the communication wire. :)
 
They can as long as the voltage on any circuit does not exceed the 300 V of the communication wire. :)
This isn't a full answer. There isn't enough information here to answer the question. ONE condition that allows or forbids it is the voltage limitation, but there are several other conditions including the Class of the wiring.
 
This isn't a full answer. There isn't enough information here to answer the question. ONE condition that allows or forbids it is the voltage limitation, but there are several other conditions including the Class of the wiring.
Could you cite a code reference?
 
No. Most electricians know the equal insulation rule in 300 3 C 1, but miss the information note in that section. The IN refers you to Art 725. I suggest you read the IN and referenced section. Also, per 90.3, the rules in chapter 7 can modify the riules in chapters 1-4, so take a look at 90.3
 
Could you cite a code reference?

He's right. See 800.133 and 725.136. The wire type is only half the story, the usage needs to be understood. The various conditions are too numerous to outline here.
 
There is a option to reclassify the class 2 Tstat wire to class 1. Class 1 wiring is done with a chapter 3 wiring method and can run in the same raceway if functionally related
 
Can 300 volt communication wire (8 conductor thermostat wire) be run in the same conduit as the power conductors rated at 600 volts. An example would be 18/8 thermostat wire in same conduit with #2 direct burial cable running from a ATS to a back-up generator?
the answer is maybe.

the thermostat wire idea suggests these are article 725 conductors and you would need to take a close look there to see what is allowed.
 
Could you cite a code reference?
There is an informational note the follows the code section that you cited that tells you where to look. Not sure why almost all code users skip over that informational note. Remember that while the note itself is not enforceable code, the section it tells you to look at is.
 
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