Can Solar DC wiring share conduit with AC power?

[Old_Skewler]

I currently have a 1-1/2" electrical conduit running to the cabin from the shed, underground, with split-phase AC power and a generator signal (control) wire inside the conduit.

I need to run 8 AWG wire from the roof to the shed. Can the new PV DC wiring run inside the same conduit with the AC power?

Thanks in advance!

 

[BobR]

I am not giving advice but you may want to read this:
NEC
Section 300.3(C)(1)

(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.

 

[pollenface]

Poking it all the way through will be interesting....

 

[timselectric]

Yes
As long as all conductor insulations are rated for all available voltages.

 

[Maitake]

I don't think so.
I put a divider in my gutter to keep pv dc and ac circuits separate.
Can't recite code but pretty sure it was in there somewhere to keep it separate.

PVDC is a bit of a wild beast.

 

[meetyg]

I was wondering the same thing. But from my research online, it's not recommended.
See:

Can DC and AC cables run in same conduit?

Can DC and AC cables run in same conduit?

www.ecosoch.com

https://www.allaboutcircuits.com/textbook/alternating-current/chpt-7/mixed-frequency-ac-signals/

ac/dc in conduit

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.)

diysolarforum.com

For example...

 

[OzSolar]

I suspect the generator signal wire has a low voltage jacket so code was busted a long time ago. I bet nobody's died so "if it fits, it ships".

 

[Maitake]

Separation of pv dc circuits
I am not an electrician...

690.31(B) PV source circuits and PV output circuits shall not be contained in the same raceway, cable tray, cable, outlet box, junction box, or similar fitting as conductors, feeders, branch circuits of other non-PV systems, or inverter output circuits, unless the conductors of the different systems are separated by a partition.

 

[Old_Skewler]

I am not giving advice but you may want to read this:
NEC
Section 300.3(C)(1)

(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.

Good find and thank you for posting it!

 

[Old_Skewler]

Poking it all the way through will be interesting....

The poking seems easy actually, it is a very straight up run and plenty of room inside the conduit... the issue could be pulling a set of two 6 AWG cables thru it after running the snake...

 

[Old_Skewler]

Separation of pv dc circuits
I am not an electrician...

690.31(B) PV source circuits and PV output circuits shall not be contained in the same raceway, cable tray, cable, outlet box, junction box, or similar fitting as conductors, feeders, branch circuits of other non-PV systems, or inverter output circuits, unless the conductors of the different systems are separated by a partition.

Interesting.. this seems to be more specific than Section 300.3(C)(1) quoted previously.

Thanks for clarifying, I will further investigate but likely I'll run another conduit.

 

[Danke]

I was going to run my PV DC wires in same conduit as GEN AC wires. Especially being that if my generator is running, I wouldn’t be getting PV power.

But worried about inspector not liking it, so I plan on separating them.

 

[Old_Skewler]

I was going to run my PV DC wires in same conduit as GEN AC wires. Especially being that if my generator is running, I wouldn’t be getting PV power.

But worried about inspector not liking it, so I plan on separating them.

I hear you... I am in similar position and don't want to have to re-do any work later on...

 

[SparkyJJO]

Whether it is required or not, I prefer to keep my AC and DC stuff separate.

 

[curiouscarbon]

Whether it is required or not, I prefer to keep my AC and DC stuff separate.

Thank you for this guidance.

AC and DC can interfere with each other by causing a magnetic field nearby which the other type is exposed to which generates some unexpected voltage in a non-electrically-conducted circuit domain.

The magnetic coupling interference between AC and DC conductors is the main reason I understand to physically separate them.

That and of course if insulation somehow fails, the physical partition limits how many circuits may be affected.

I'm still designing a system for myself and plan to design for separate AC and DC conductors in raceways etc as much as possible.

Thanks again

 

[Wet1]

If running separate conduits for AC and DC conductors, how far should they be apart if in the same trench (recommended depths for each)?

 

[timselectric]

If running separate conduits for AC and DC conductors, how far should they be apart if in the same trench (recommended depths for each)?

No seperation distance requirement.
18" below the surface. Unless under a driveway, then 24".

 

[Wet1]

No seperation distance requirement.
18" below the surface. Unless under a driveway, then 24".

Thanks Tim!

 

[Danke]

Just wondering if anybody had ideas or examples of putting a barrier into a large trough to separate AC and DC?

 

[timselectric]

Just wondering if anybody had ideas or examples of putting a barrier into a large trough to separate AC and DC?

Yes, I've done barriers many times.
Just bend a piece of sheet metal into an L on the back side to give you a mounting flange. And fold the front side over to give it some rigidity.
Access to a metal break makes it very simple.