Can AC and DC share the same conduit

[William-Mc]

Morning
I have a jacuzzi in my sun room, the PV panels are outside the sunroom
My DB is in the centre of the house under the staircase
The 220v power supply for jacuzzi runs in a 5 metre conduit, screwed to the ceiling, through two walls, to the sunroom
Can I share the same conduit for the 48v DC coming from combiner box in sunroom to the inverter under staircase
The jacuzzi is almost never used during periods of sunshine
5kva inverter, 4 x 260ah batteries, 6 x 330w panels, inverter set to UPS mode, via a 2-way switch
Wires used are 4mm² twin and earth to jacuzzi and 10mm² from combiner box
I have googled the question and found many YES and NO replies, I would really like to share one conduit on ceiling
A friend says I should either use two conduits or wrap one set of wires in tin foil
What about using black automotive flexible plastic split conduit around one set of wires
Thanks
William

 

 

 

 

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AC and DC can't be in the same conduit. You won't get a CoC for that.

Spend a few hundred and rent a large hammer drill and drill a new hole for the DC cabling. I know that's not what you wanted to hear... sorry

[William-Mc]

Thanks, not what I wanted to hear, how far apart should I put the conduits
I have a hammer drill, holes in walls not a problem, it's the unsightly conduits
Touching, side by side, not too bad I suppose  

 

 

[NigelL]

Another option is to use 110x50 trunking that has an internal divider to separate the AC and DC sides.  See https://www.efapel.pt/en/products/cable-trunkings/10-series-distribution-cable-trunkings 

I bought this trunking and corner sections etc. at AC-DC

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40 minutes ago, William-Mc said:

unsightly conduits

 

31 minutes ago, NigelL said:

trunking

I agree with Nigel here. Conduit can be ugly, but IMHO trunking looks better. You get trunking with two compartments. You could also run trunking within trunking, or even conduit inside trunking. As long as there is clear physical separation.

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44 minutes ago, William-Mc said:

how far apart should I put the conduits

They can run directly side by side. I think the reason for not allowing them in the same conduit is partly that if your insulation fails in some manner you can have high voltages passing onto low-voltage wiring, but also that there is an element of confusion for anyone who works on the system.

If we were purely concerned about wires touching, it would have been sufficient if both cables were armoured in some way. PV cable is pretty thick already, and if you had Surfix running in the same conduit I am sure it would be perfectly safe... but it's still a bit of a surprise to a future electrician working on it.

[William-Mc]

Thanks a lot for your help, I will put the twin and earth into a smaller conduit inside the bigger one

Conduit or trunking, not sure, it is the white plastic stuff Builders sell, the cover strip clips on
Builders call it PVC conduit,  RS Components call it Schneider Electric Mini Trunking

Not sure why electrician will get confused, the wires split after going through the wall into the room under the staircase
Twin and earth is white, goes to old DB on one wall, the PV wires are red, black and green and goes to the inverter on the opposite wall, width of staircase apart
William

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3 hours ago, William-Mc said:

Conduit or trunking, not sure, it is the white plastic stuff Builders sell, the cover strip clips on

Trunking is the square strips where the cover comes off and you smack it all down once all is in place. Conduit is a round pipe, and you get 20mm, 25mm, 40mm and 50mm diameters, 20mm being the most common one.