Mixing line and low voltage wires in a wireway

J

JoeNorm

Senior Member
Location
WA
I am wiring my first in-ground pool.

There is a mixture of low voltage control stuff and line voltage(lights, mainly) that has been routed to a mechanical room. All the conduits come up in a way that would make the use of a gutter ideal. But I am wondering if all those wires can be mixed within that enclosure?

The insulation on the lower voltage stuff says 300v, for whatever that is worth. And the highest voltage equipment is 240v.

Did I read in another post that solar components can all be mixed together? If that is the case why couldn't the same be done for a pool? It is all part of the same system after all.

Thanks, any insight appreciated.
 
See NEC Art. 300.3 (C)(1). From what I read ,If under 1000v, all the conductors occupying the same enclosure shall have insulation equal to at least the maximum voltage applied to any conductor in the enclosure. If your max voltage is 240v, I would say your 300v insulated conductors are ok.
 
Rick 0920 said:
See NEC Art. 300.3 (C)(1). From what I read ,If under 1000v, all the conductors occupying the same enclosure shall have insulation equal to at least the maximum voltage applied to any conductor in the enclosure. If your max voltage is 240v, I would say your 300v insulated conductors are ok.
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While this section is often cited, nearly all
miss the IN following it. So like infinity days you may have an issue. Low voltage is a very vague term.
 
I will have a look at the code. It's too bad it is not a little more straight forward. You'd think if the insulation is all within the voltage range things should be fine.
 
JoeNorm said:
I will have a look at the code. It's too bad it is not a little more straight forward. You'd think if the insulation is all within the voltage range things should be fine.
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From memory I think it's 725.136 or something close to that in Article 725.
 
JoeNorm said:
I will have a look at the code. It's too bad it is not a little more straight forward. You'd think if the insulation is all within the voltage range things should be fine.
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I disagree. I believe the intention is that Class 2 wiring is run without the mechanical protections of Class 1, power and lighting wiring, so, if a short should occur between the conductors in the raceways or enclosures, then the portion of the Clas2 wiring that is not protected, will present a shock and/or fire hazard.
 
Class 2 and 3 circuits can share the wireway (or any type of raceway) with power and light only if they are wired with Class 1 or power and light methods. You cannot for example put CL3R or UTP (catX) cable in there. There also is or has been a restriction to mixing only when the low voltage circuit is 'functionally related' to the power and light circuits.

The restriction on solar circuits applies only to PV DC circuits, essentially DC connected directly to solar panels. Those must be kept separate from everything else.
 
Strathead said:
I disagree. I believe the intention is that Class 2 wiring is run without the mechanical protections of Class 1, power and lighting wiring, so, if a short should occur between the conductors in the raceways or enclosures, then the portion of the Clas2 wiring that is not protected, will present a shock and/or fire hazard.
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I wonder how many times this has happened in history. My guess is not many.
 
Yeah, the hazard is pretty minor imho.

To be compliant in actual installation terms it's quite a bit more straightforward than the process of reading through and understanding article 725 (as of 2023 articles 724 thru 726).

Basically...
If you can run your low voltage with the same wiring used for normal (<1000V) line voltage then all is okay, just try not to mix in the low voltage where it doesn't make sense for it to be. You can further save a little money and conduit fill by using TFFN in 16awg or 18awg. See 715.49(B) in the 2023. The TFFN I've seen is always crosslisted as MTW which makes it okay for wet as well as dry locations.
 
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