ac/dc in conduit

[Traveler004]

Anyone know if you can run both ac and dc conductors in the same conduit? I'm planing to run dc to dc converter to a bunch of usb outlets in the house and I want to put the wires in the same conduit that I have AC wires in. (Assume conduit fill is respected.)

 

[Supervstech]

As long as the insulation ratings are the same, it shouldn’t be an issue.
I would not do it, simply because it could be confusing.
audio equipment can pick up noise from the ac lines, and induced voltage might be an issue if you have high voltage AC, and very low voltage dc long runs.

 

[nosys70]

no , as per electrician rule, low and high tension, AC and DC cannot be mixed.
after that, you can break the rule, it will not blow up the thing, but insurance could find the easy way to not pay you in case of problem.

 

[Steve_S]

NO, it's a BAD IDEA you will get field effect and more... DC & AC should always be separate.
Lookup DC Wiring in Conduits & Raceways, there are a lot of discussions on that.... LOOK at credible sites there is a bit of FUD out there.

 

[newbostonconst]

Not recommended. It would suck to have to re due everything if it didn't work.... Just do it right the first time in my opinion.

 

[TheDroidsYouAreLookingFor]

It will work without issues, USB cable won't care and ac cables won't care. I may or may not have done the same thing with active USB adapters and power for projectors in ceilings. Side note: Plenum rated cat 5 cable can be terminated for usb and doesn't burn or make toxic fumes when burning. It's used to run data through air conditioning and heating vents... legally too!

Edit: check max distance for usb. You may need active adapters to reach 30-50 ft. I don't want you saying it didn't work after you try to run a 150 ft usb cable and say it didn't work. Lol I've seen some crazy stuff in I.T.

 

[Supervstech]

USB Cables are shielded, so interference is going to be minimum... the cable ends pulling through the conduit is going to drastically limit the number of cables that will fit, so, unless you are building the cables, wire fill isn’t going to be an issue... 40% fill is the code limit..

 

[rjbuckley]

National electric code prohibits it. You can mix in a box if you have a non-conducting shield between them. Maybe put the inverter outdoors and run the AC in the conduit? I can't put batteries outdoors because of winter....

 

[Supervstech]

National electric code prohibits it. You can mix in a box if you have a non-conducting shield between them. Maybe put the inverter outdoors and run the AC in the conduit? I can't put batteries outdoors because of winter....

I would like you to show the code prohibiting this..

 

[Supervstech]

There are low voltage and high voltage conductor limits, because the conductor insulation must be separated from each other, but I can find zero codes prohibiting ac and dc runs if the same wire insulation is used.

 

[rjbuckley]

OK. I am wrong. Taking the word of the local electrical inspector is bad form. Checked with my son the E2. Not illegal, just bad practice as someone already pointed out. Sorry.

 

[Supervstech]

Yeah, I scoured my code book, and couldn’t find a code forbidding it, as long as the insulation is equal rated, it is legal... but I wouldn’t do it.

 

[DerpsyDoodler]

if i have ac lines in conduit and dc lines next to it (but not in the conduit) in the same raceway, is that OK?

 

[Supervstech]

if i have ac lines in conduit and dc lines next to it (but not in the conduit) in the same raceway, is that OK?

It is all ok.
It just makes differentiation cumbersome.
if you use different color conductors it makes things easier.

 

[DerpsyDoodler]

It is all ok.
It just makes differentiation cumbersome.
if you use different color conductors it makes things easier.

im not worried about confusion. dc is 4/0 lines for the inverter. ac lines just need to come back up from the underbelly to feed the coach. i can find a different path, but prefer not to make any more new holes than i have to. i want to either identify a way to have them coexist in a standard/approved way or find a different route for the ac lines.

 

[Supervstech]

Coexisting is completely code compliant.

 

[A.Justice]

It's been mentioned a few times here, but ghost voltages (induction, I think) could be an issue for AC run with DC. I've personally had funky readings on stuff run in the same conduit. I would think that it could be an issue for voltage sensitive DC stuff on that circuit.

I had a line that was off at the breaker read almost 50 volts because it was run with a bunch of other wires. For AC runs of the same voltage, there shouldn't be an issue, for lower voltage DC runs, there might be.

 

[Supervstech]

It's been mentioned a few times here, but ghost voltages (induction, I think) could be an issue for AC run with DC. I've personally had funky readings on stuff run in the same conduit. I would think that it could be an issue for voltage sensitive DC stuff on that circuit.

I had a line that was off at the breaker read almost 50 volts because it was run with a bunch of other wires. For AC runs of the same voltage, there shouldn't be an issue, for lower voltage DC runs, there might be.

That may be true, but NEC codes do not have rules against it.
As long as insulation on the conductors is rated for the same voltages, there aren't code rules against it.

 

[DerpsyDoodler]

That may be true, but NEC codes do not have rules against it.
As long as insulation on the conductors is rated for the same voltages, there aren't code rules against it.

is there any way i can shield one from the other so i don’t have to worry about induced voltages? if i can reliably mitigate the potential problems without breaking the bank, I’m game.

 

[MarkSolar]

In my barn I have the fence charger line (~8000v pulsed), Ethernet line, and camera video line zip tied to the outside of a conduit carrying 60A ac. I've never had a problem. If you had a low voltage dc signal line carrying the launch signal for a nuclear device I probably wouldn't do it. But otherwise I wouldn't worry about it.