Solid vs stranded wire

[BlueMarblePA]

I am about to start my grid tied, permit approved solar panel installation on my roof. I want to buy wire, but I just realized I am not sure whether I am supposed to get solid or stranded THHN.

My design is PV wire to soladeck to 50 feet of 3/4" EMT to Solaredge 7.6kw inverter. I am planning 10 Awg (black, red, black, red) and 8awg green. This will be thhn through emt conduit. The DC will stay exterior to house.

Then from main electrical panel to AC disconnect to solaredge inverter, I am planning 40amp breaker and 8AWG thhn (red, black, white, green) through emt and liquid tight. This will be a transition from inside to outside.

Do I buy stranded wire for the DC and solid for the AC?

 

[Ampster]

Do I buy stranded wire for the DC and solid for the AC?

Voltage and DC or AC doesn't matter. Stranded is much easier to pull.

 

[42OhmsPA]

Stranded is much easier to pull.

Yes! I'm still bitching at myself for being cheap and buying solid ground, that was the shittiest most miserable pull I've ever done. Trying to pull 2 stranded and a solid from the roof at dusk with only me, never again.

 

[BlueMarblePA]

Voltage and DC or AC doesn't matter. Stranded is much easier to pull.

Thank you. This is helpful

 

[farmhand]

In skeewl I learned stranded is up to 10% more efficient as the electrons travel on the surface area, not (in) the conductor. Stranded has more surface area when added up compared to solid. Of course less headaches as mentioned above

 

[brb58]

In skeewl I learned stranded is up to 10% more efficient as the electrons travel on the surface area, not (in) the conductor. Stranded has more surface area when added up compared to solid. Of course less headaches as mentioned above

No skin effect with DC. Even at 60Hz, you don't even need to worry about it for the most part.

 

[chrisski]

From what I read here on this thread, stranded or solid, but stranded is easier to pull.

I do wonder if this applies to all AOJ (authority of jurisdictions).

 

[Ampster]

I do wonder if this applies to all AOJ (authority of jurisdictions)

AFAIK the AWG and insulation are all that matter.

 

[DougfromdaUP]

In skeewl I learned stranded is up to 10% more efficient as the electrons travel on the surface area, not (in) the conductor. Stranded has more surface area when added up compared to solid. Of course less headaches as mentioned above

See if they’ll refund your tuition

 

[Bluedog225]

I recall the Victron manual wanted fine stranded. I wonder why?

 

[Ampster]

I recall the Victron manual wanted fine stranded. I wonder why?

It is used in vehicles and boats because stranded doesn't fatigue and break from vibration.

 

[farmhand]

See if they’ll refund your tuition

I would but it's already paid for itself so I'm good.

 

[featherlite]

The manual for the Victron MPPT 100/50 says:

 

[featherlite]

deleted duplicate post

 

[Old_Skewler]

The manual for the Victron MPPT 100/50 says:

View attachment 135202

I am shopping for wires to connect to and from my Victron and I came around the same requirements above for fine stranded wires. Were you able to find wires in the market that meets this strand requirements?

For instance, I found a 8 AWG 19-Stranded THHN but nothing close to what Victron wants:

https://www.amazon.com/gp/product/B09LWGTNY4/ref=ox_sc_act_title_2?smid=A3LZLP6ULNJFN7&psc=1

 

[JoeHam]

I am shopping for wires to connect to and from my Victron and I came around the same requirements above for fine stranded wires. Were you able to find wires in the market that meets this strand requirements?

Temco.

See wire count table on this page :

TEMCo WC0085 Welding Cable - 6 AWG 30 ft - Black

temcoindustrial.com

 

[Old_Skewler]

Temco.

See wire count table on this page :

TEMCo WC0085 Welding Cable - 6 AWG 30 ft - Black

temcoindustrial.com

Very good find, thank you.

 

[Warpspeed]

Fine stranded will always be much nicer to work with because of its flexibility.

There is only really one situation where its inferior. If its used outdoors or where water can get to it, especially at the ends, it will suck up water like sponge. The copper will quickly go green and turn to powder and then go open circuit. This is particularly a problem with buried cables, where even a single pin hole will let in water, and the moisture will then travel an amazing distance in both directions.

Thicker and fewer strands, has the same problem but to a much lesser extent. Tinned copper wire is much better than bare copper wire.
So if its in a boat, or up on a roof, be mindful of possibly wet conditions.

 

[pvgirl]

If you need listed fine stranded wire look for MTW or Machine Tool Wire.

 

[Warpspeed]

Just to be clear, the difference between tinned copper cable and bare copper cable.
Tinned copper has much better resistance to moisture and corrosion and is what should be used outdoors.