control wire

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Location
Virginia
Iam pulling #14 stranded with 600 volt insulation into a wire way thats being used by the control contractor.His wires are 18/2 sheilded cable with 300v insulation carrying 24v ac.My conductors are also carrying 24v ac.The control guy say's I can not use his wire way becouse of the different insulation value. If we are carrying the same voltage I do not see why use it!
 

bphgravity

Senior Member
Location
Florida
Re: control wire

Refer him to the 2002 NEC 300.3(C). This code states that conductors of different insulation ratings CAN occupy the same raceway as long as the applied voltage does not exceed the minimum voltage insualtion rating of any conductor. So basically, up to 300-volts may be applied to these conductors in the same raceway.
 

stamcon

Senior Member
Re: control wire

(99NEC) 300-3(c)(1) 600 Volts, Nominal or Less -
"Conductors of circuits rated 600 volts nominal, or less, ac circuits and dc circuits 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."

There are some exeptions under 725-54 dealing with mixing class 1, 2 and 3 circuits, though.
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Re: control wire

You must know the classification of these circuits before the question can be answered. These are Article 725 circuits, but we don't know if they are Class 1, 2 or 3. This information is needed as per 90.3 the rules in Chapter 7 modify those in Chapter 3. If they are both Class 1 or both Class 2 there is no problem, but if one is Class 1 and the other Class 2 they cannot be mixed.
Don
 

tom baker

First Chief Moderator
Staff member
Re: control wire

300.3(C) is often incorrectly cited as allowing different volages in the same enclosure, box or raceway. As Don pointed out 90.3 states the rules in Article 725 modify the rules in chapers 1-4.
And we miss the fine print note at the bottom of 300.3(C).
 
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