Parts for squirrel damaged junction box on Trina panel

[tastewar]

I have four 250W panels that were damaged by squirrels, and our solar provider replaced them (at my cost...) so I asked for the old panels back. It appears that the only damage is to the leads that come out of the junction box. So what was returned to me did not have the leads with the MC4 connectors, and also apparently the "nuts" (there's a better word, of course...) that tighten the leads to the junction box. Our provider tells us that Trina don't sell the spare parts, hence the need to replace the entire panels.

Here are some pictures in a flickr album of the situation:

https://www.flickr.com/photos/tastew...57670593669370

I have found these inexpensive solar junction boxes on eBay:

http://www.ebay.com/itm/191890876668

And wonder if I can scavenge the leads and nuts from them. Anyone who's dealt with lots of these (different brands, etc) know if those "nuts" (i.e diameter and threading) are standard??

[solarix]

Those are called "strain-reliefs" or some people call them "glands". You should be able to find something suitable in a local supply house or hardware store. If not go to Digikey.com or Mouser.com. The Leads ought to be PV wire - or could use USE-2 wire. Digikey also sells the MC4 connectors although you really need the right crimper to install them. Lots of solar suppliers sell solar wire of various lengths with a MC4 connector on each end. You just cut these wherever you want to get a lead of each polarity.

[bcroe]

My experience the best prices will be on the internet. Digi frequently provides me with excellent service, often at a premium rate. Bruce Roe

[tastewar]

Thank you both! Any reason to think the glands on the eBay product wouldn't be compatible? At $6 per, I suspect it would be hard to beat for 2 glands and 2 leads.

[Mike90250]

When installing new wires into a J box, how does a person decide which cable goes to which terminal? How to tell the polarity of the MC connectors, is a + or - molded into them ?

[bcroe]

When installing new wires into a J box, how does a person decide which cable goes to which terminal? How to tell the polarity of the MC connectors, is a + or - molded into them ?

Well gee, just check a good panel. Put a meter on the PV. Bruce Roe

[littleharbor]

MC-4 connectors.jpg
Output cables from panel, MC-4 connectors. Top of photo is the negative female connector, bottom one is the positive Male connector. Amphenol and Tyco connectors are similar.

[Robert1234]

If you look closely at the original picture posted, the + and - are indeed imbedded in the plastic. Additionally if you can't pickup the panel voltage there with a meter to determine the polarity, then the panels are toast anyway. It does appear that simply the leads were yanked out of the box. Everything else looks intact. Simple lead change.

If these panels are for play, have you considered just soldering in some leads with MC4's on the ends of them?

[tastewar]

Sure! I've even considered connecting wires without the fancy connectors! It just seems like $6 to repair each panel back to "nearly new" condition would be a good investment. I haven't seen MC4 leads cheaper than that, really.

[bcroe]

Sure! I've even considered connecting wires without the fancy connectors! It just seems like $6 to repair each panel back to "nearly new" condition would be a good investment. I haven't seen MC4 leads cheaper than that, really.

It only took a minute to find 10 MC4 pairs for $6.01 (free shipping). Make repairs, extension cords, experiments. For this environment, I don't
use standard electronic connectors or wiring. I am guilty of soldering them. Bruce Roe

[tastewar]

You are awesome! Of course, if I didn't care about the glands, I would just use wire I have on hand -- no need for the MC4's either. But it pleases me to (hopefully...) make them good as new. I ordered those boxes; will report back how they work out.

[tastewar]

The boxes arrived. I was able to remove the cables with MC4 ends, and the connectors crimped onto the "bare" ends of the wires seem a perfect fit for the connectors inside the Trina boxes. But the glands are not interchangeable. The glands that came with the boxes I bought are clearly a stand-alone part, and are simply meant to seal around a hole in a chassis. But the Trina boxes have a threaded piece as an integral part of the box. So those won't work as direct replacements. May just end up using silicone, or other sealant, around where the wires enter the box and call it a day.