Separating the DC in a solar system.

[Isetech]

We all know that you cannot run AC and DC and comms cables together, what about battery cables and solar panel cables?

You battery cables are generally between 12 VDC and 48 VDC and in older solar systems the voltage was around 120 VDC.

Things have changed, the question is can you fit a DC Distribution board and use it to house all the DC safety gear and fuses?

Can I fit one DB, fit the fuse protection for the batteries and the solar panel fuses in the same DB?

Can I run the all the DC cables in the same wireway, if the batteries are 48 VDC and the solar panels are 450 VDC?

[GCE]

Generally you will not run battery and PV together
Battery will need a fuse in a holder because of the bidirectional current and DC C/Breakers cant all handle bi directional current
Pv you need to go into an isolator , fuse and onto DC surge arrestors per string
Surge arrestor is DC and designed for PV panels

If you do have them in the same trunking the cables would need to be able to handle the highest voltage

[Dylboy]

So can PV cables be in same trunking, conduit, wireways as AC cables ?

I see it on almost every single solar installation

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[Dylboy]

Valsa supplier have a AC and DC protection box... Double tier with both the AC protection and the DC protection... Is that allowed ? They bark on about being SANS what what but then I see this.

Also seen them use an AC isolator for DC, I asked the sales guy and he just said well they had engineers design and build it....

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[Isetech]

Generally you will not run battery and PV together
Battery will need a fuse in a holder because of the bidirectional current and DC C/Breakers cant all handle bi directional current
Pv you need to go into an isolator , fuse and onto DC surge arrestors per string
Surge arrestor is DC and designed for PV panels

If you do have them in the same trunking the cables would need to be able to handle the highest voltage

Everyone connecting batteries and solar panels, take note of these comments. If you have double insulated solar DC cables which should be rated to 600 or 1000 VDC, makes sure your battery cables are also rated to the string total open VOC.

[GCE]

So can PV cables be in same trunking, conduit, wireways as AC cables ?

I see it on almost every single solar installation

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No they may not - Unfortunately certain PV installers keep saying there are no regulations governing PV - They seem to miss the point that PV is Electrical installation work as defined and falls directly under SANS10142-1
Clause 6.1.10 is clear

6.1.10 Conductors that form part of a d.c. installation shall not be run in the
same wireway as conductors that form part of an a.c. installation.

[GCE]

Generally you will not run battery and PV together
Battery will need a fuse in a holder because of the bidirectional current and DC C/Breakers cant all handle bi directional current
Pv you need to go into an isolator , fuse and onto DC surge arrestors per string
Surge arrestor is DC and designed for PV panels

If you do have them in the same trunking the cables would need to be able to handle the highest voltage

6.1.7 If conductors that operate at different voltages run in the same wireway,
the insulation of each conductor shall be able to withstand the highest
conductor voltage in the wireway. Alternatively, the conductors shall be
separated by a continuous barrier of insulating material or earthed metal.


6.3.2.2 Conductors shall be so insulated as to withstand the highest
temperature and voltage to which they are likely to be exposed.

[Isetech]

I dont see a problem with using sprag to sleeve the wire to protect the cable /wire, it just cant touch at any point, even at a 90 degree cross.

The 90 degree crossing of cables/wires has nothing to do with voltages.

Networks, frequencies and stuff is a completely different topic, in some cases if a VSD is used you would also need to consider cable routes and cross over, shielded cables, etc.

[Dylboy]

No they may not - Unfortunately certain PV installers keep saying there are no regulations governing PV - They seem to miss the point that PV is Electrical installation work as defined and falls directly under SANS10142-1
Clause 6.1.10 is clear

6.1.10 Conductors that form part of a d.c. installation shall not be run in the
same wireway as conductors that form part of an a.c. installation.

I agree, DC and AC always seperate.

I do see with these inverters and the layout of the install or nature where it is they have cross over.

Can DC cut through AC wireway ?
I say no as it is in the same wireway but I want to make sure.

I think I have seen one install where AC and DC was seperate everywhere

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[Isetech]

I agree, DC and AC always seperate.

I do see with these inverters and the layout of the install or nature where it is they have cross over.

Can DC cut through AC wireway ?
I say no as it is in the same wireway but I want to make sure.

I think I have seen one install where AC and DC was seperate everywhere

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My understanding is, so long as you protect the cables from each other. You cant just cut a hole in the trucking and have all the cables touching each other.

The reality is you never every stop it from happening.