SPD Off-grid Wiring?

[crunnells]

Hey guys,

I just got 2 SPD300's to protect my upcoming PV array install and to protect the AC side of my house. The PV side makes total sense, but I'm trying to figure out how to wire up the AC side. Let me give you a quick backstory.

We're off-grid, currently running an IOTA transfer switch hooked up to our Honda 2000 generator and a 1250watt inverter. I have a MNDC250 enclosure where my Classic is connected, along with the inverter and battery hookup wires.

Now, I don't really have an AC in/AC out like the documents show. Our house distribution panel is small so I never wired up a master "off" breaker figuring that the DC disconnect and turning off the genset does the same thing.

Where should I be hooking the AC side of the SPD? Should I hook it up in the transfer switch to protect the house output and the inverter input?

Or, should I just ignore the AC side and put a second one to protect the DC side of the inverter in the DC disconnect panel?

[Halfcrazy]

I would definitely put one on the AC side somewhere. If all the wiring between the inverter and the transfer switch is fairly short I would put it where it is the most convenient but if you run off the generator much I would probably install it on the AC out side of the transfer switch. If the system is all 120vac and there is no charger in the inverter I would use the red for Inverter out and black for generator out.

Ryan

[crunnells]

I've got the inverter and the transfer switch on the same wall, so it's a 3' run from one to the other. About another 12' from the TS into the main panel. The genset is a little further away (~25, but I've got a 50' extension cord on it at the moment).

I like your suggestion of connecting the inverter and the generator... There shouldn't be any problems with that right? I don't want the one to fry the other.

[crunnells]

I got the SPD on my PV array wired in, but only one of the blue LEDs light up; the other one is off. Is this a wiring problem on my end, or is there a problem with the unit?

[niel]

say how you have it wired and maybe that'll give us a clue.

[Halfcrazy]

I got the SPD on my PV array wired in, but only one of the blue LEDs light up; the other one is off. Is this a wiring problem on my end, or is there a problem with the unit?

Thats normal. One LED is on the DC negative and it will be referenced to ground through the GFP in the system. Thus there will be no voltage present so no LED on that channel.

Ryan

[crunnells]

say how you have it wired and maybe that'll give us a clue.

I've got two strings of PV panels wired into a MNPV3, with the SPD wired as shown in the manual (red wire to PV+, black wire to PV- bus bar, green to ground bus bar).

Thats normal. One LED is on the DC negative and it will be referenced to ground through the GFP in the system. Thus there will be no voltage present so no LED on that channel.

Okay, I see now that's it's mentioned in the documentation. I'd suggest adding a paragraph somewhere that explains that only one LED will be on in certain setups. Thanks!