725.48

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ceb58

ceb58

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Raeford, NC
I want to see if I am over thinking this one

725.48 Conductors of Different Circuits in the Same
Cable, Cable Tray, Enclosure, or Raceway.
Class 1 circuits
shall be permitted to be installed with other circuits as
specified in 725.48(A) and (B).
(A) Two or More Class 1 Circuits.
Class 1 circuits shall be
permitted to occupy the same cable, cable tray, enclosure, or
raceway without regard to whether the individual circuits are
alternating current or direct current, provided all conductors
are insulated for the maximum voltage of any conductor in the
cable, cable tray, enclosure, or raceway.
The way I read this is it is the maximum rated voltage of the conductors not what they are carrying. Example:
If you have a 120/240 feeder wire in conduit and it is THHN/THWN rated at 600v and you also pull in control wire with it, that wire must also have an insulation rating of 600v.
Am I over thinking this one?

 
I read that as the actual voltage of the circuit, not the rated voltage of the insulation.

I also note that 725.48(A) does not apply to your installation. You have Class 1 conductors with power conductors. 725.48(A) only applied when you have multiple Class 1 circuits in the same raceway.

725.48(B)(1) applies and that section does not say anything about the rating of the conductors. That would mean that 300.3(C)(1) would apply to your installation and it more clearly written than 725.48(A).
(C) Conductors of Different Systems.
(1) 600 Volts, Nominal, or Less. Conductors of ac and dc circuits, rated 600 volts, nominal, or less, shall be permitted to occupy the same equipment wiring enclosure, cable, or raceway. All conductors shall have an insulation rating equal to at least the maximum circuit voltage applied to any conductor within the enclosure, cable, or raceway.
Click to expand...

Note that 725.48(B)(1) says that the Article 725 Class 1 control conductors can only be installed in the same raceway as the power circuit conductors if they are functionally associated with those power circuit conductors. Your post said that the Class 1 conductors are being installed with "feeder" conductors. If the power conductors are really feeder conductors (per the NEC definition) it would be unlikely that there would be functionally associated control conductors.
 
The charging statement is " 2 or more class 1 circuits"

Class 1 Circuit. The portion of the wiring system between the load side of the overcurrent device or power-limited supply and the connected equipment.
(A) Class 1 Power-Limited Circuits. These circuits shall be supplied from a source that has a rated output of not more than 30 volts and 1000 volt-amperes.

I agree with Don 300.3(C)(1) for your analysis
 
I think it would say "...provided all conductors are insulated for the maximum voltage rating of any conductor in the cable, cable tray, enclosure, or raceway..." if they wanted you to look at the rating of the insulation.

I agree it's voltage going through the conductor. That's something you have control of and will not change.
 
don_resqcapt19 said:
I read that as the actual voltage of the circuit, not the rated voltage of the insulation.

I also note that 725.48(A) does not apply to your installation. You have Class 1 conductors with power conductors. 725.48(A) only applied when you have multiple Class 1 circuits in the same raceway.

725.48(B)(1) applies and that section does not say anything about the rating of the conductors. That would mean that 300.3(C)(1) would apply to your installation and it more clearly written than 725.48(A).


Note that 725.48(B)(1) says that the Article 725 Class 1 control conductors can only be installed in the same raceway as the power circuit conductors if they are functionally associated with those power circuit conductors. Your post said that the Class 1 conductors are being installed with "feeder" conductors. If the power conductors are really feeder conductors (per the NEC definition) it would be unlikely that there would be functionally associated control conductors.
Click to expand...

I agree 300.3 (C)(1) dose make it clearer. The debate was about 2 utility sensing wires and 2 start wires in the same conduit with the feeder wires for a generator. The difference is in the wording "at least the maximum circuit voltage applied" verses "insulated for the maximum voltage of any conductor" that to me says you could not mix 300v and 600v insulation rating.
 
ceb58 said:
I agree 300.3 (C)(1) dose make it clearer. The debate was about 2 utility sensing wires and 2 start wires in the same conduit with the feeder wires for a generator. The difference is in the wording "at least the maximum circuit voltage applied" verses "insulated for the maximum voltage of any conductor" that to me says you could not mix 300v and 600v insulation rating.
Click to expand...

And I disagree with that because if you are not talking about applied or nominal, there is no reason to include the word "circuit".
 
ceb58 said:
I agree 300.3 (C)(1) dose make it clearer. The debate was about 2 utility sensing wires and 2 start wires in the same conduit with the feeder wires for a generator. The difference is in the wording "at least the maximum circuit voltage applied" verses "insulated for the maximum voltage of any conductor" that to me says you could not mix 300v and 600v insulation rating.
Click to expand...
As long as the maximum voltage on any conductor in the raceway is 300 volts or less, you can mix 300 and 600 volt rated conductors.
 
ceb58 said:
I agree 300.3 (C)(1) dose make it clearer. The debate was about 2 utility sensing wires and 2 start wires in the same conduit with the feeder wires for a generator. The difference is in the wording "at least the maximum circuit voltage applied" verses "insulated for the maximum voltage of any conductor" that to me says you could not mix 300v and 600v insulation rating.
Click to expand...

What did we do this time?.......
 
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