Multi-Strand Wire (100+ vs 8)

[chemist308]

I sourced some of my equipment from a solar and wind company in Missouri, including 8 AWG PV wire. The insulation felt similar, but the wire was stiff. Since these were the same folks that sold me a decent inverter, and they're knowledgeable--this stuff is literally all they do--I thought nothing of it and ran the wiring from my pass through to the box on my roof.

Now I read the owners manual to my Victron after hooking everything up, and it's saying to never use that type of wire for PV array or solar charge controller. What it pictures as acceptable is much more like the 10AWG I used to link my panels and the 4 AWG I used to feed from my controllers to the batteries.

Is there really a risk or something wrong with using cable that has thicker stands and a lower strand count?

[MoonShadow_1911]

I sourced some of my equipment from a solar and wind company in Missouri, including 8 AWG PV wire. The insulation felt similar, but the wire was stiff. Since these were the same folks that sold me a decent inverter, and they're knowledgeable--this stuff is literally all they do--I thought nothing of it and ran the wiring from my pass through to the box on my roof.

Now I read the owners manual to my Victron after hooking everything up, and it's saying to never use that type of wire for PV array or solar charge controller. What it pictures as acceptable is much more like the 10AWG I used to link my panels and the 4 AWG I used to feed from my controllers to the batteries.

Is there really a risk or something wrong with using cable that has thicker stands and a lower strand count?

The only thing I can think of is a wire with 100+ strands is much more flexible than a wire with 8 strands. I would recommend emailing Victron and inquiring directly with them.

[Scott'n'Wendy]

The wire you used will not be a problem. The lugs in the victron equipment MAY be specially designed for fine strand though. And the difficulty of shaping stiffer wire may stress those lugs more - which could be the reason they insist on fine strand wire.

FYI, electricity runs mostly on the surface of wires. Higher strand count wire has a higher current carrying capacity - for wire of the same gauge.

[LMagelitz]

FYI, electricity runs mostly on the surface of wires. Higher strand count wire has a higher current carrying capacity - for wire of the same gauge.

*much more of a concern at higher frequencies than 60hz. At 8awg it’s irrelevant.

[chemist308]

*much more of a concern at higher frequencies than 60hz. At 8awg it’s irrelevant.

Just to be sure I understand you, my use of 8 AWG is running 2 series of panels in parallel down to the solar charge controller (2 series of 210w panels to 1 controller and 2 series of 100W panels to the other). Does that change anything? Expecting voltages around 50 volts and amperages around 25 amp max at 50 volt.

[Scott'n'Wendy]

At 8awg it’s irrelevant.

It was just an FYI, not really relevant to the op's question. But compare dlo to regular xlink. Very significant difference at 60hz. As I said, not a concern for the op.

[LMagelitz]

Just to be sure I understand you, my use of 8 AWG is running 2 series of panels in parallel down to the solar charge controller (2 series of 210w panels to 1 controller and 2 series of 100W panels to the other). Does that change anything? Expecting voltages around 50 volts and amperages around 25 amp max at 50 volt.

You should be fine, as others have said. If your concerned, give Victron a call about the stranding you are using.

@scott’n’wendy I think dlo is an RHH insulation type, compared to XHH for xlink, and THHN which is likely what OP has. They line up in the NEC as having same ampacity. You can have wildly differing ampacities based on diff applications.

[jkwilson]

It was just an FYI, not really relevant to the op's question. But compare dlo to regular xlink. Very significant difference at 60hz. As I said, not a concern for the op.

Skin effect doesn’t come into play until about 20KHz. No issue at all at 60Hz.

If you want to get really technical, electricity doesn’t flow in the wires at all. It flows in the fields around the wires.

[chemist308]

Thank you all for the replies. From the owners manual, the concern was wire surface area and resistance due to thicker strands. For the life of me I can’t see the difference at such low voltage, but was figuring that might be the reason all battery cable is super flexible multi strand.

[Scott'n'Wendy]

Thank you all for the replies. From the owners manual, the concern was wire surface area and resistance due to thicker strands. For the life of me I can’t see the difference at such low voltage, but was figuring that might be the reason all battery cable is super flexible multi strand.

It's because electricity flows on the surface. More surface area...more flow capabilities. More strands = more surface area = more flow = less resistance. Regardless of frequency. Applies to DC as well.

But I really thought the multi strand requirement was going to be about flexibility and putting less strain on the victron lugs.