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Thread: Power and low voltage same raceway

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    Power and low voltage same raceway

    Have an application where a # 18 cable to control ballast and #12 for power has to go to each light. Problem is we want to run it in the deck with these cables under one PVC jacket( cable) and NYC amended the code not allowing low and line voltage in the same raceway. Any ideas how to still do this efficiently in the deck? Thanks

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    Quote Originally Posted by mstrlucky74 View Post
    Have an application where a # 18 cable to control ballast and #12 for power has to go to each light. Problem is we want to run it in the deck with these cables under one PVC jacket( cable) and NYC amended the code not allowing low and line voltage in the same raceway. Any ideas how to still do this efficiently in the deck? Thanks
    Does the NYC amendment still apply when the low voltage conductors are insulated for the higher voltage? That configuration was specifically allowed under NEC. Also no NYC exception for low voltage wires associated with the operation of the same equipment that the high voltage wires are feeding?

    If you are only using an outdoor-rated cable assembly in a protective sheath, there is no "raceway" for them to share. A cable, by itself, is IMHO not a raceway.
    Of course the point where you break the wires out of the cable to go to high and low voltage terminals might still be considered part of one raceway, I suppose. Either that or part of a single listed control assembly, without an intervening raceway?

    How are the wires terminated at each light/luminaire? Is there even any provision for attaching two separate raceways there?

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    Quote Originally Posted by GoldDigger View Post
    Does the NYC amendment still apply when the low voltage conductors are insulated for the higher voltage? That configuration was specifically allowed under NEC. Also no NYC exception for low voltage wires associated with the operation of the same equipment that the high voltage wires are feeding?

    If you are only using an outdoor-rated cable assembly in a protective sheath, there is no "raceway" for them to share. A cable, by itself, is IMHO not a raceway.
    Of course the point where you break the wires out of the cable to go to high and low voltage terminals might still be considered part of one raceway, I suppose. Either that or part of a single listed control assembly, without an intervening raceway?

    How are the wires terminated at each light/luminaire? Is there even any provision for attaching two separate raceways there?
    I believe it does apply when LV conductors are insulated for the higher voltage. No sure about the association of LV cables operating same equip as HV, will check. Good point about the raceway. So a pvc coated mc cable you would not consider a raceway? You lost me in your paragraph where the wires breakout of the cable assembly.
    THe LV wires terminate on an Lutron Ecosystem ballast and the 120v wires terminate....hmm thata a good question. The detail surely shows the LV & HV cables going to light fixture and those who have looked into this understand that.

    Thanks.

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    Quote Originally Posted by mstrlucky74 View Post
    I believe it does apply when LV conductors are insulated for the higher voltage. No sure about the association of LV cables operating same equip as HV, will check. Good point about the raceway. So a pvc coated mc cable you would not consider a raceway? You lost me in your paragraph where the wires breakout of the cable assembly.
    THe LV wires terminate on an Lutron Ecosystem ballast and the 120v wires terminate....hmm thata a good question. The detail surely shows the LV & HV cables going to light fixture and those who have looked into this understand that.

    Thanks.
    2011 NEC, Article 100 Definitions:

    Raceway. An enclosed channel of metal or nonmetallic materials designed expressly for holding wires, cables, or busbars, with additional functions as permitted in this Code. Raceways include, but are not limited to, rigid metal conduit, rigid nonmetallic conduit, intermediate metal conduit, liquidtight flexible conduit, flexible metallic tubing, flexible metal conduit, electrical nonmetallic tubing, electrical metallic tubing, underfloor raceways, cellular concrete floor raceways, cellular metal floor raceways, surface raceways, wireways, and busways.
    Cable is not defined, but if conductors cannot be removed from or added to the inside of the protective covering of a cable, that protective covering would not constitute a raceway. (NEC does not allow you to assemble raceways with the conductors already inside them. You have to pull them in after assembly. Except for something that is an integral part of listed equipment.)

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    The voltage is not the real factor in the NEC rules for control wires in the same raceway or cable as the power wires. The Class of the power supply for the control wires is the major factor.
    It appears the control wire for that ballast can be either Class 1 or Class 2. Class 1 conductors are permitted to be installed with the power conductors as long as they have insulation rated for the highest voltage that any of the associated conductors is carrying. In general Class 2 circuit conductors cannot be installed with power conductors.
    Don, Illinois
    "It is the first responsibility of every citizen to question authority." B Franklin

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    Quote Originally Posted by GoldDigger View Post
    2011 NEC, Article 100 Definitions:



    Cable is not defined, but if conductors cannot be removed from or added to the inside of the protective covering of a cable, that protective covering would not constitute a raceway. (NEC does not allow you to assemble raceways with the conductors already inside them. You have to pull them in after assembly. Except for something that is an integral part of listed equipment.)
    Great explanation...thanks.

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    Quote Originally Posted by don_resqcapt19 View Post
    The voltage is not the real factor in the NEC rules for control wires in the same raceway or cable as the power wires. The Class of the power supply for the control wires is the major factor.
    It appears the control wire for that ballast can be either Class 1 or Class 2. Class 1 conductors are permitted to be installed with the power conductors as long as they have insulation rated for the highest voltage that any of the associated conductors is carrying. In general Class 2 circuit conductors cannot be installed with power conductors.
    Thanks. So how exactly do you determine whether a wire is class 1 or 2? The power supply gives that info? I have been trying the find the cose section that explains Class 1&2 wire in the same raceways as power wires.....which section?THanks

    EDIT: Is it 725.48? Thanks.
    Last edited by mstrlucky74; 07-12-13 at 08:38 PM.

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    Quote Originally Posted by don_resqcapt19 View Post
    The voltage is not the real factor in the NEC rules for control wires in the same raceway or cable as the power wires. The Class of the power supply for the control wires is the major factor.
    It appears the control wire for that ballast can be either Class 1 or Class 2. Class 1 conductors are permitted to be installed with the power conductors as long as they have insulation rated for the highest voltage that any of the associated conductors is carrying. In general Class 2 circuit conductors cannot be installed with power conductors.
    My second question is just what the NYC amendment actually says, if this is not just the applicable NEC cycle's restrictions being applied.

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    Also beyond what the code requires, their may be problems caused by capacitive coupling of the higher voltage current to the low voltage control wires which may or may not affect the operation of the light controls, you might want to check with the manufacture to see if this could be a problem, I saw this problem first hand on a Leviton remote motion detector where the installer had ran the LV conductors from the relay within the same conduit that the HV conductors ran in, it kept the lights on even hours after anyone triggered the motion detector, once the motion detector pulled the relay in the phantom voltage was just enough to keep it pulled in, ran a 18/3 class 2 cable between the relay and MD and it worked just fine.
    Wayne A. From: N.W.Indiana
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    Quote Originally Posted by mstrlucky74 View Post
    Thanks. So how exactly do you determine whether a wire is class 1 or 2? The power supply gives that info? I have been trying the find the cose section that explains Class 1&2 wire in the same raceways as power wires.....which section?THanks

    EDIT: Is it 725.48? Thanks.
    For Class 2 and 3 conductors the rule in is 725.136(A).

    Class 2 or 3 power supplies are so marked. The voltage and current limits for those power supplies are found in Chapter 9, Tables 11A and 11B.
    Don, Illinois
    "It is the first responsibility of every citizen to question authority." B Franklin

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