Stand Alone Solar Arc-fault protection devices.

FilterGuy

What, me worry?
I have been studying the NEC requirements for wiring solar panels and one of the requirements is arc-fault protection if the PV array is at 80V or more.
However, when I search for PV arc-fault protection product.... I find no stand-alone products.
  • Some SSRs have it built in.
  • Most grid-tie inverters have it built in.
  • Some Solar optimizers have it built in.
  • Some combiners have it integrated.
  • Some Rapid disconnect systems have it built in.
I have not found a stand alone product.... Does anyone know of one?
 

Hedges

Photon Sorcerer
Dirty Pictures!

 

Hedges

Photon Sorcerer
Here ya go


But I only see commercial size units there - 250A
Haven't found any small ones.



"Integrating AFCI functionality within the PV system inverter eliminates the cost and effort of installing additional arc-fault circuit protection components to meet 2011 NEC section 690.11 requirements."

Sounds like they do exist, or did back then.
 

Maast

Compulsive Tinkerer
Sorry, I didnt see this before. After a truely stupid amount of searching I've found one and only one solution: A Sensata PVAF-T or PVAF-R, you thread your Array wire through it and it has an internal NC switch that opens if it detects an arc fault. You can use this signal to drive a disconnect. Module requires 12-24v power applied. It says its not for use with optimizers but tigo says they will not interfere with arc fault detection circuits. Guess I'll find out. Right now there are PVAF-Ts on ebay for cheap.

What I'm using it for is to shut down my panel optimizers, I'm injecting the signal break it into the rapid shutdown loop.

And if the inspector doesnt like it, he can kiss my foot 'cause it's the only thing out there that doesnt require me to repurchase very expensive charge controllers.
 
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FilterGuy

What, me worry?
That is an interesting device. I had seen it before but did not pay much attention to it because it is only a partial solution.

I like the idea of tying it into a rapid disconnect.

As I was looking at it just now it occured to me you could repurpose a PV GFP breaker and set it up like this:
1610268768137.png
When the signal from the detector goes high it would trigger the SSR wich would dump enough current through the GFP breaker to trip it.

I don't know if an inspector would accept it but it would probably work.
 

Maast

Compulsive Tinkerer
Take a look at the inside of Outbacks AFCI combiner box, you'll see it's got what looks like a PVAF in it. And a gigavac contactor too. They sell their combiner and initiator for $1400 and it has about $200 in parts in it.
PVAF-T_Series.jpgicsbox.JPG
 

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FilterGuy

What, me worry?
Good Catch. I figured it must be used in other products someplace.

The contactor is interesting. Notice it has 4 smaller wires going to it. That tells me it is either a latching relay or has secondary contacts for a feedback loop... It is hard to tell from the picture

1610302362075.png


What did you have to do to interface it to your rapid disconnect?
 

Maast

Compulsive Tinkerer
All the panels will have Tigo TS4-O optimizers that are also capable of rapid shutdown. There is a wireless 'keep alive' signal sent by a gadget called a CCA along with a TAP. As soon as the power is cut to the CCA/TAP the optimizers shut down.

I'm running the 24V <1A power for the CCA/TAP through the NC switch in the PFAP. The 120v AC for the 24V wall wart DC power is fed direct from the Radian so as soon as the inverter is shut off the panels go into rapid shutdown. The same DPST switch used to cut the inverter also routes power from the chargery to the main gigavac contactor on the battery bank.

This way I get both: rapid total system shutdown, or just AFCI array panel rapid shutdown. Total cost, about $300 plus the optimizers. I have serious winter shading issues so I was always going to have optimizers.

Its dead simple, but you wouldnt believe how many brain bytes and google time I had to burn to come up with it. I've literally spent several weeks on and off trying how to figure how to meet the AFCI and rapid shutdown code requirements and not break the bank.

If the PFAP internal relay can't handle the power for the CCA I'll use the signal to drive a relay control board instead. I got 3 of them: one to screw up, one to use, and one as a spare.
 
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