Low and High Voltage together?

[jessebmcneely]

Can i use 12VDC (for LED's) in same conduit as 120/240VAC?

 

[Dennis Alwon]

Can i use 12VDC (for LED's) in same conduit as 120/240VAC?

Read art 300.3(C). If the conductors have an insulation rating at least as high as the maximum voltage applied to any conductor then it should be good. Check the FPN but I am not sure it applies for LED.

 

[jessebmcneely]

!!

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Can i use 12VDC (for LED's) in same conduit as 120/240VAC?

FPN??....I read that....i have a 30Amp 240vac in the same conduit, each conductor is only carrying a max of 120v, so do i need the insulation rating on the DC wires to be rated for at least 240v or would 120 suffice?

 

[infinity]

The FPN references Article 725. If the LED's have a class 2 or class 3 power supply then they cannot occupy the same raceway as power or lighting conductors regardless of their insulation value.

FPN: See 725.136(A) for Class 2 and Class 3 circuit conductors.

 

[Dennis Alwon]

FPN??....I read that....i have a 30Amp 240vac in the same conduit, each conductor is only carrying a max of 120v, so do i need the insulation rating on the DC wires to be rated for at least 240v or would 120 suffice?

The way I read it if you have 240 V circuit then your max. applied voltage would be 120V to any conductor, therefore the LED must have insulation rated 120V minimum. I think you will find that the wires will have a 300V rating anyway.

 

[don_resqcapt19]

The way I read it if you have 240 V circuit then your max. applied voltage would be 120V to any conductor, therefore the LED must have insulation rated 120V minimum. I think you will find that the wires will have a 300V rating anyway.

This is likely an Article 725 circuit and even if it is a Class 1 circuit there are still limits to installing it with power circuits, no matter what the voltage rating of the conductor insulation is. 725.48(B)(1)

 

[gadfly56]

The way I read it if you have 240 V circuit then your max. applied voltage would be 120V to any conductor, therefore the LED must have insulation rated 120V minimum. I think you will find that the wires will have a 300V rating anyway.

Perhaps I misunderstand, but I read it that the conductor insulation has to match. If your "high" voltage wire insulation is rated to 600VAC then your LED wire insulation must also be rated to 600VAC. It's not about the actual voltage on the wire. But I could be wrong...

 

[don_resqcapt19]

Perhaps I misunderstand, but I read it that the conductor insulation has to match. If your "high" voltage wire insulation is rated to 600VAC then your LED wire insulation must also be rated to 600VAC. It's not about the actual voltage on the wire. But I could be wrong...

I think you are.

300.3(C)(1)...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.

But I am not convinced you can mix them no matter what the insulation rating is.

 

[iceworm]

Hi guys and girls -

I haven't been ignoring anyone, I've been working flat out for the last several months - didn't have much time to stop in.

However, this one caught my eye, since the subject recently came up. I think it is under the same code sections as the OP.

My application is control wiring in a 480V, 1200A switchboard, consisting of 4-20ma instrumentation loops, PLC low level inputs, PLC low level outputs, mixed in the same plastic channel with #12 480V conductors tapped to the 480V bus that go to fuseblocks (5A). then go to 480/120V PTs. I don't think they should all be mixed in the same Panduit channel.

I'm looking at 2011, 725.133, 136, 139:
I'm interpreting 4-20ma instrumentation, PLC low level inputs, PLC low level outputs, all as class 2 or class 3 - the same as your 12V LEDs. I'm thinking 725.136 specifically says that one should separate by barrier, or distance from power circuits. Infinity discussed this is post 4. The separation specifics are in 725.136.A - I.

Now, if the wiring were all in one enclosure, and the panel was constructed by a UL panel shop to UL1558, maybe it is okay to have then all mixed in one channel. That's what I'm researching now. It just doesn't seem right to mix them.

iceworm

 

[tom baker]

Hi guys and girls -

I haven't been ignoring anyone, I've been working flat out for the last several months - didn't have much time to stop in.

However, this one caught my eye, since the subject recently came up. I think it is under the same code sections as the OP.

My application is control wiring in a 480V, 1200A switchboard, consisting of 4-20ma instrumentation loops, PLC low level inputs, PLC low level outputs, mixed in the same plastic channel with #12 480V conductors tapped to the 480V bus that go to fuseblocks (5A). then go to 480/120V PTs. I don't think they should all be mixed in the same Panduit channel.

I'm looking at 2011, 725.133, 136, 139:
I'm interpreting 4-20ma instrumentation, PLC low level inputs, PLC low level outputs, all as class 2 or class 3 - the same as your 12V LEDs. I'm thinking 725.136 specifically says that one should separate by barrier, or distance from power circuits. Infinity discussed this is post 4. The separation specifics are in 725.136.A - I.

Now, if the wiring were all in one enclosure, and the panel was constructed by a UL panel shop to UL1558, maybe it is okay to have then all mixed in one channel. That's what I'm researching now. It just doesn't seem right to mix them.

iceworm

Panel shops do this all the time. But on the field wiring side its a violation, unless the field wiring is Class 1 and its functionally related.

 

[hockeyoligist2]

Personal experience, that I ran in to recently. Even though the installation was code compliant, 115v in same conduit as 24 v, contractor installed. The 115 shorted to the 24v and burned out 2 PLC's. A coworker got shocked, slightly, but that was his fault, he assumed that there was only 24v's in the cabinet and didn't check . In a factory/facility environment I run them separately, just because I don't want to run in to problems later on. After all, I have to repair all that stuff, sometimes in the middle of the night!

 

[gadfly56]

I think you are.

But I am not convinced you can mix them no matter what the insulation rating is.[/SIZE][/FONT][/SIZE][/FONT]

I stand corrected.:dunce: