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AC and DC cable wiring CoC

Featured Replies

2 hours ago, Gnome said:

For trunking I don't think there is a difference because the same risk exists.  But I could have sworn they run cables from both power and other systems (ie Air Conditioning systems logic cables) in a cable tray.  But I'll confirm.  I can't see anything explicitly in the regs other than, keep your AC electrical wire away from your non-AC electrical stuff.  I expect the answer is going to be no mixing in a cable tray or you need to put it in a conduit or something.  But TBD.

I think the key to this is that one should provide separate channels for different services (e.g. AC wiring and DC Wiring) where the channels ensure both physical separation and an insulation barrier between the different services. See the following extract from SANS 10142-1:2017 Ed2.

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I believe that the split-trunking, as mentioned in my previous post, meets these requirements by implementing two separate channels.

Edited by NigelL

Can confirm, just checked with an engineer, they 100% don't share cable trays with AC power in buildings.  Non power wires run in isolated conduits.

On 2021/02/03 at 11:41 AM, Gnome said:

there are not professional engineers that sign for electrical installs

I think it depends where in SA you install a PV system. The CoCT for example requires professional Engineer sign off before they approve the system.

26 minutes ago, Fuenkli said:

The CoCT for example requires professional Engineer sign off before they approve the system.

This is only for grid-tied PV systems. For off-grid systems a COC is enough.

Off-grid installations have always been allowed. There was some confusion around the rules, but that has been resolved quite a while ago now.

The latest documentation from the CoCT is pretty clear about the requirements.

Just some info regarding DC wiring in SANS 10142-1-2:201x embedded generation installations. I guess this standard should be followed to stay on the safe side of things even for off-grid systems.

Inspection and Test report (Section 4)Nr. 7 - Different circuits are separated electrically? - If this is ticked no it is not compliant!

Again on Table 8.1: Inspection requirements. (DC system Equipment Selection and Erection) Nr. 26. The DC circuits are electrically separates from AC circuits.

Then under Surge Protection 6.2.6 d. Where a system features longer DC cables, longer than 50meter consideration shall be given to screened, armored or metal conduit/trunking.

On 07/02/2021 at 10:30 PM, Tariq said:

Wasn’t the issue that the off grid inverter could not be connected to the grid at all ??

If it was connected surely it wouldn't be off grid?

18 hours ago, Gerrie said:

Inspection and Test report (Section 4)Nr. 7 - Different circuits are separated electrically? - If this is ticked no it is not compliant!

Again on Table 8.1: Inspection requirements. (DC system Equipment Selection and Erection) Nr. 26. The DC circuits are electrically separates from AC circuits.

ok, excuse me, but separated electrically to anyone who is not completely off his rocker should imply that they run on separate conductors, which, hey they would have to, wouldn't they? Separated electrically certainly does not imply that DC circuits are socially or otherwise distanced from AC circuits.

The usual - "I love specifications, there are so many to choose from and to interpret in the way that suit me."

  • 1 year later...

Ok so long and the short, 

Solar DC Cables do not need metal trunking?


How do I know for sure> My solar installer has quoted for plastic trunking when I specifically asked for metal?  Do I fight them to change it to metal or is this not necessary?

Cable run is 20 to 30m MAX.

Edited by Zapnologics

11 hours ago, Zapnologics said:

Ok so long and the short, 

Solar DC Cables do not need metal trunking?


How do I know for sure> My solar installer has quoted for plastic trunking when I specifically asked for metal?  Do I fight them to change it to metal or is this not necessary?

Cable run is 20 to 30m MAX.

Came here to ask exactly this too. Do we have clarity?

  • 8 months later...

I am in the process of getting quotes from installers. When I enquired about the conduit used outside between inverter in the garage and the DB box inside the house, one installer stated that there is a change coming to the regulations that metal conduit may no longer be used.

 

Anyone heard of such a change?

  • 1 year later...

Only saw this topic after I allready posted. 

Can I put PV DC wires in conduit through an ACDB and into trunking to the inverter which has AC wiring and the DC batt cable. 

Thank you. 

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