I Need Help, Will this system work?

[coreyschlueter]

DIYer here trying to build out my first system. I have done hours and hours of research and I just want the community's opinion on my setup. Thanks

36 of these bad boys - https://tandem-solar-systems.com/product/longi-lr6-60pb-305ma-305w-black-ac-module/

Run in three strings of 12 connected to this - https://tandem-solar-systems.com/product/enphase-q-ba-3-1p-60-aggregator/

From there #6 wire from roof to this - https://tandem-solar-systems.com/product/enphase-x-iq-am1-240-4-iq8-combiner-with-iq-envoy/

Then I will be doing a line side tap with these. - https://smile.amazon.com/dp/B06XCYRRJQ?psc=1&ref=ppx_yo2ov_dt_b_product_details

one question I still need answered is where to put the disconnect and also what size disconnect I need.

Looking forward to everyone's impute!!!

 

[burgerking]

36 x 250W panels = 9000W
3 strings of 12 panels= 3000W / string (Voc ~ 480V)
Imp per string ~ 8-10A

one question I still need answered is where to put the disconnect and also what size disconnect I need.

Safety requires that you install Fuse/MCB (~15A per string) + SPD in that Combiner Box.
And then another Fuse/MCB (~45A) + SPD near the SCC/Inverter.
I was told that this Fuse/MCB can qualify as PV Disconnect.

However, you might still want a fancier PV Disconnect like this.

This Switch should be rated at least 45A, 600V.

 

[GregTR]

These panels have Enphase microinverters already, he's tying 12 of them in parallel and combines the parallel AC in a AC junction box/aggregator. It is not a DC combiner box. There is no 480V Voc here...

I'm no microinverter expert, but I'm pretty sure you're going to need to tie this setup into your regular breaker panel with a breaker, you can't just do the tap on the main line like you are thinking, there has to be a breaker for sure. I'll also venture that you probably also need an A/C disconnect somewhere in this setup that will isolate all of this from the grid with a single pull.

Here is the field wiring diagram for iQ7: https://support.enphase.com/s/article/IQ-7-IQ-7plus-Field-Wiring-Diagram

 

[burgerking]

These panels have Enphase microinverters already

I did not notice the micro-inverter on the panels.
my bad!

my earlier post = invalid

 

[coreyschlueter]

These panels have Enphase microinverters already, he's tying 12 of them in parallel and combines the parallel AC in a AC junction box/aggregator. It is not a DC combiner box. There is no 480V Voc here...

I'm no microinverter expert, but I'm pretty sure you're going to need to tie this setup into your regular breaker panel with a breaker, you can't just do the tap on the main line like you are thinking, there has to be a breaker for sure. I'll also venture that you probably also need an A/C disconnect somewhere in this setup that will isolate all of this from the grid with a single pull.

Here is the field wiring diagram for iQ7: https://support.enphase.com/s/article/IQ-7-IQ-7plus-Field-Wiring-Diagram

If I have a fusible disconnect do you think I would be able to get away with the line side tap? I don't have the room in my panel for more breakers and I don't want to replace it. Also the panels say 305 watts (Pmax/W) on the DC side but on the AC side power output is 250 VA. What number should I use to size my system?

 

[GregTR]

Sizing should be on the AC side. The 305W panels will clip sometimes but will produce 250W longer during the day than if they were 250W panels.

You can buy tandem breakers to squeeze some of your existing ones together. Only caveat with using those is to make sure you phase them right as both legs on a tandem breaker are the same phase.

So if you have this setup now in your breaker:
Phase A - circuit 1
Phase B - circuit 2
Phase A - circuit 3
Phase B - circuit 4

You should do this:
Tandem 1 Phase A - circuit 1
Tandem 1 Phase A - circuit 3
Tandem 2 Phase B - circuit 2
Tandem 2 Phase B - circuit 4
New Dual Breaker (phase A and B) - Enphase tie in.

Having a fused disconnect doesn't preclude the breaker requirement.