How many lightening arrestors needed for a 120/240 system?

[Nashville]

Hello!
I need to figure out how many lightening SPD's I need if I have a 120/240 system with dual 3648 Grid tie Outbacks, two classics with the Dual Bypass / Tom's Weird Slider. I've already figured out what I need for the combiner. Is it 6 SPD's like the stacked diagram shows? Is there a diagram on this wiring?

Thank!

Brit in Nashville

Do I get a Midnight Solar shirt for all the dough that I have spent on your stuff? lol

[Halfcrazy]

Brit
For 2 inverters in a 120/240 system with two Classics the minimum would be 1 for each classic and one per inverter for 4 SPD300's I would also highly recommend one at the AC mains panel as this is where most of the nasty's will come from. I also could say putting one in the combiner and possibly one on the DC battery is not a bad idea but would be down the priority list. below is the order of priority in my mind and how they wire in:

1-SPD300 in the AC mains panel Red to L1, Black to L2 and green to ground
2+3 SPD300's on the DC input of the Classics. Red to PV+, Black (with the white heat shrink on it) to PV- and green to ground
4+5 SPD300's on each inverter. Black to AC in, Red to AC out and green to ground
6- SPD300 in the combiner. Red to PV+, Black (with the white heat shrink on it) to PV- and green to ground
7- SPD115 on the battery in the Epanels. Red to Bat+, Black with the white heat shrink to Bat- and green to ground.

Ryan

[Nashville]

Thanks Ryan.

Should I use the SPD 150's at the Classics and Inverters, since I have 2-arrays of nominal 120 volt dc coming from my combiner to each of the classics?

Thanks!
Brit

[Halfcrazy]

No I would stay with the 300's the SPD115 is to low it can bleed at those voltages.

Ryan

[Nashville]

Ok, thanks Ryan! Ordering your recommended parts now.

[Westbranch]

Nashville, do you have grid available?  Just wondering about the hook up on the inverters Ryan recommends..?

[Nashville]

Yes, grid tie interactive.

[Alanbrad]

a minimum of three is required for it, with proper parallel or in series connected.