Wiring a 6 into 1 combiner box wire size.

[Watch Me Build]

here's the specs on the panel. Trying to do s2p6 into the combiner box. So 12 panels total.

The run from the combiner box to the PIP 3048LV-MK is 30 ft. Can I get away with 6awg wire? And what's the most cost effective wire I can go with when running through underground conduit?

Also what gauge wire from the panels to the combiner box?

 

[Tecnodave]

6 ga. wire is rated at 60 amps maximum,

calculation.....6 X 10.10 ( worst case short circuit current) = 60.60 times 1.25 safety margin = 75.75 amps

also in the NEC....continuously operated device , i.e. able to operate at maximum power for more than 2.0 hours requires an additional ampacity of 1.25 ............thus 1.25 times 1.25 is 1.56 .....1.56 times 60.60 is 94.68 worst case current....94.68 amps worst case 2 ga barely makes it

.however this worst case is very unlikely to occur in a solar installation since operating at short circuit over 2 hours is so unlikely the more correct calculation would be 6 X 9.58 X 1.25 =71.85 amps 2 ga. will be fine here

individual series panels to combiner 10.10 amps times 1.25 is 12.65 amps normal maximum current 14 ga wire is rated 15 amps under the NEC for household use

Best wire type THHW (thermoplastic-hot-hot-weatherproof) 105 deg C

assuming underground conduit....assumes water....waterproof wire required

for dry conduit THHN (thermoplastic-hot-hot-not weatherproof)

THHN and THHW is commonly available at home improvement stores

 

[Watch Me Build]

I was going by this chart, for the THWN-2 (the 90° C heading) . That's why I thought I could get away with the 6awg. Maybe the 4? The 2 seems like overkill going by this.

Chart

 

[TomC4306]

I am using 8 gauge from a 6-1 combiner. 45 feet.
That is the largest diameter wire that will fit in the MPP solar pip 3048. And it was a pia getting it in there clean.
But I'm running 3s6p. 90volts, 7.5 amps per string.
Call it 8 amps * 6 strings 48 amps.
ABYC chart says 70 amps with 90c wire AWG8.

Google Image Result for https://boathowto.com/wp-content/uploads/abyc_tables.png

 

[Tecnodave]

ABYC chart says 70 amps with 90c wire AWG8.

ABYC is the American Boat and Yacht Club

That has nothing to do with NEC as required by the building department and household insurance.

I did assume we were discussing a dwelling

And you did forget the NEC required multiplier 1.25 times 1.25 equals 1.56 times maximum continous amps @2.0 hours

 

[TomC4306]

Okay, but he's going to have to downsize to 8 gauge to fit it in the charger.
Don't think he's looking to get it permitted and inspected using an MPP solar unit.

 

[Watch Me Build]

Yeah, no permit or inspection, but I do want to do it correctly.

8 awg, definitely isn't large enough for the panels I have

 

[Tecnodave]

Okay, but he's going to have to downsize to 8 gauge to fit it in the charger.
Don't think he's looking to get it permitted and inspected using an MPP solar unit.

The other thing is the insurance......most have in the agreement ”compliance with the code”

Not everything that I do is “exactly code” but so near that the inspectors let me skate on not being permitted

My system is all U.L. listed, made in America,

 

[TomC4306]

Hmm.
Who in America is making inverters and batteries?

 

[Tecnodave]

Hmmm.......Schnerider Electric, Magnasine, Trace, Exeltech, Morningstar, Interstate Battery, Tesla 18650 and 20700 cells

<EDIT> dont know how I missed Midnight solar in there...inverters coming soon


Many manufacturers out there
my main bank of batteries are cnuk.....Rolls-Surette

All of my American gear has far exceeded expected lifetime
None of my chinese gear has made it one year

 

[Supervstech]

Why aren't you doing 3S?

 

[Tecnodave]

I am betting that Elon will open a LFP megafactory in Nevada

 

[Tecnodave]

Why aren't you doing 3S?

?

 

[Supervstech]

?

The panels, you are running 2S I'm curious why you aren't using 3S

 

[Tecnodave]

Personally I am running my panels 2S due to the fact that the voltage conversion ratio of 72 volts to 28 volts (2.5 to 1)is far more efficient than 108 volts to 28 volts (3.85 to 1) more efficent equals less generated heat equals longer life.

I have long life gear

Never had a power outage on main system since its been All-American

 

[Bud Martin]

ABF is doing it: https://www.teslarati.com/american-battery-factory-lfp-gigafactory-tucson-arizona/

I am betting that Elon will open a LFP megafactory in Nevada

 

[Tecnodave]

ABF is doing it: https://www.teslarati.com/american-battery-factory-lfp-gigafactory-tucson-arizona/

I just knew that was coming with emphasis on electric vehicles.

Crown, Gillig, and BYD Busses are all LFP as well as most of the yard tuggers (mini tractors that shuffle containers around at the ports are LFP).

BYD (China) has built a transit bus factory in Lancaster, California to serve American and Canadian Transit Markets.

All their busses are LFP.......the first busses that have passed all NTSB testing at the first pass, rollover, crash, fire safety, etc.

 

[Watch Me Build]

Why aren't you doing 3S?

Because I think it exceeds or is too close to exceeding the working voltage of the 3080.

 

[Watch Me Build]

Because I think it exceeds or is too close to exceeding the working voltage of the 3080.

Oh I thought you were asking me.

 

[TomC4306]

Personally I am running my panels 2S due to the fact that the voltage conversion ratio of 72 volts to 28 volts (2.5 to 1)is far more efficient than 108 volts to 28 volts (3.85 to 1) more efficent equals less generated heat equals longer life.

I have long life gear

Never had a power outage on main system since its been All-American

Dude, hijacked his thread. This one's not about you.