Best ways to connect PV to THHN

[nm611]

I have an existing 16W ground array and am preparing to build another 16KW array next to it.
I am planning to use AWG 14 or 12 PV wire with MC4 connectors to connect to the strings, but then all the wires go into a junction box and then a 250ft conduit. Its a 1.5inch conduit. The existing array uses 7 AWG THHN (3 strings + GND) conductors running through the conduit - and I want to add another 6 conductors (3 strings). I am leaning to using THHN 14 AWG, since the conductors will be 10A max, and THHN has thinner insulation to ensure I stay within 60% usage of the conduct .
What is the best most water proof way to transition from the PV to THHN wire.
The old array used 2 to 1 screw in connectors since its was 6 strings going down to 3.
This year the junction box and 3/4 of my array ended up underwater due to heavy rain - so I should plan for some possible submersion for periods of a couple of days.
I am located in California - Bay area. Welcome any recommendations. Thanks.

 

[12VoltInstalls]

What is the best most water proof way to transition from the PV to THHN wire.

A probable ‘best’ is a waterproof junction box where you make up the connections inside with bare crimps and a couple layers of adhesive heat shrink. Alternatively a terminal strip/block (no jumpers) with crimped eye connectors on each inside a waterproof JB. Alternatively a “solar combiner box.”

A combiner box makes the most sense to me.

 

[BentleyJ]

These submersible Polaris connectors may be of help.

Submersible/Direct Burial Blue

 

[MrM1]

Perhaps busbars inside a water proof box.

 

[nm611]

Thanks for the tips - those polaris connectors look interesting, but I could achieve a pretty good connection like @12VoltsInstalls suggested- I'll also try to re-run the size calculations to see if I can fit the PV up the conduit - eliminating the need for a transition.

 

[MrM1]

We did pv wire through conduit to the combiner. Eliminates transition. Transitioned at the combiner. But not saying it's the cheapest.

 

[12VoltInstalls]

but I could achieve a pretty good connection like @12VoltsInstalls suggested

Not this brand and a different application but I’ve used these clones in the past and they were way handier than expected in a boat.

 

[Supervstech]

These are readily available. You could make the connection, pack with electrical paste, and heat shrink tight.

direct burial connection - Google Shopping

 

[Danke]

If it’s outside, even though it’s in conduit, don’t you want to use THWN for moisture?

”transition from the PV to THHN wire.”

 

[Supervstech]

If it’s outside, even though it’s in conduit, don’t you want to use THWN for moisture?

Ya pretty much cannot buy THHN anymore. It’s all THHN-2 which has wet resistance.

 

[nm611]

You are correct I was thinking of THHN-2, but failed to call it out.
You folks are all so helpful - appreciated.

 

[12VoltInstalls]

transition from the PV to THHN wire

I’d be disinclined to use wire nuts myself. I suppose that makes them ‘serviceable’ but I feel like ring terminals to a terminal block would be better. In my mind; ymmv?

 

[mvick30]

dinkle block

 

[12VoltInstalls]

dinkle block

I just put those in somebody’s basement to run the PV to their AIO.
They did say UL Listed so…