Buried Solar DC and 120VAC Conduit; proximity

[12VoltInstalls]

I’m pretty sure I’ve seen threads on this… coupla searches and I couldn’t find what I needed.

Plan:

• “Stationary RV” - 25’ Camper- ~65 feet from my shop building
• 0ne conduit to contain six 10ga 120VAC conductors: two green, two neutral, two hot. One ‘set’ will serve generator output to camper, one will serve inverter output from camper to to shop.
• AIO will receive generator input for charging battery bank if needed. (AIO is not connected to camper 120VAC system, and can’t be unless main inverter is physically disconnected in case someone worries about that) The AIO inverter serves only as an SCC unless I wind up needing to connect ‘house’ system to it
• Second conduit to contain 4 pairs of 10ga / 12ga thhn from 2500W solar panel array mounted to shop feeding 4 separate SCC’s (one of which is the AIO).
• I have buried and tamped in a pressure treated post to mount a weather box for disconnects and standard RV ‘shore power’ pedestal outlet and inlet, and will run watertight MC4’s into a separate weatherproof JB to connect the four solar panel strings.

All other devices and configurations are ‘handled’ and irrelevant to my question.

Question:

How close can the two conduits (one containing AC, one containing DC) in a trench be to each other? They are inches apart.

Code compliance or inspection is a non-issue here, and I’m ignoring that aspect.
The aspect that crossed my mind was inductive transfer between the two conduits. Is that an issue to be concerned about?

I don’t know why i didn’t think of this when I dug the trench…and buried the conduit. Over the summer the DC solar cables and 120VAC lay side by each on the grass and I’ve experienced no problems or oddities I’m assuming putting thhn in conduit next to each shouldn’t be an issue either but I don’t know everything; I do recall phone and tv cable conduits having to be separated from AC service conduit(s) by 48” when I was doing construction work and supervision, but I’ve never had to think about solar cabling before.
Thanks in advance for your comments.

 

[CoolWill]

You're fine. It's done all the time with much higher voltages and currents.

 

[pvgirl]

The conduit provides the needed seperation of the ac and dc circuits

 

[richard cabesa]

45 years in home building and have no problems of ac/dc in the same ditch . Just don’t put them in the same conduit

 

[12VoltInstalls]

45 years in home building and have no problems of ac/dc in the same ditch . Just don’t put them in the same conduit

Working on ~35 years for me!

But course not in the same conduit; I just recall conversations regarding inductively introduced ripple/noise and meters ‘seeing’ AC waveforms on solar cables; what’s been mentioned in the past is people talking about it potentially interfering with the mppt functions.

You're fine. It's done all the time with much higher voltages and currents.

The conduit provides the needed seperation of the ac and dc circuits

So the 4’ of separation is just a telecom function/rule/caution?

 

[CoolWill]

Working on ~35 years for me!

But course not in the same conduit; I just recall conversations regarding inductively introduced ripple/noise and meters ‘seeing’ AC waveforms on solar cables; what’s been mentioned in the past is people talking about it potentially interfering with the mppt functions.


So the 4’ of separation is just a telecom function/rule/caution?

Yeah. Or a specific utility rule. But it's not an electrical code rule.

 

[Shimmy]

So the 4’ of separation is just a telecom function/rule/caution?

If you have unshielded data cables in one conduit and AC power in another for a long run then greater separation can be warranted. But in reality, you commonly see combined-service trenches supporting Cable, Telco, and Power.

It can cause issues, but it is pretty rare unless the AC phases are separated into different conduits or you have current imbalance between parallel sets.

 

[12VoltInstalls]

Thanks