Solar panel fires!

[Spiffy Solar]

Squirrel problem is very real

What kind of maintenance is there to do with the wires under the panels and in conduit all the way to the inverters? I thought solar panels and inverters were pretty much maintenance free.

I've got hundreds of installs under my belt as well and laughed at the salesman trying to sell us squirrel guard in the warehouse one morning. That's just how it was reported, personally I think it was a failed connection in a bp panel which has happened a lot lately.

You may have "hundreds of installs under your belt" and just be working in areas without a squirrel (or pigeon) problems. I talked to one installer whose first two installs, ever, got hit by squirrels. That was in Minnesota.

It is a relatively rare problem, but to a customer with squirrel damage, it's not a problem to be scoffed at. And that customer is going to want that system protected.

Arching from squirrel damage has definitely started fires, too. I heard directly of one in Maryland, from the installer. Fortunately, the homeowner came home, saw smoke and was able to take care of it quickly.

The real question is, how often does it happen? National solar leasing companies report that it's about 1% in some areas (Long Island, for instance). And that's just in one year. Other areas may never experience the problem at all. But undoubtedly, the more solar that gets installed, the more problems we'll see with critters.

My own neighborhood has a huge pigeon problem. That's how my business got started.

Here's the back of a panel, scorched by arching caused by a squirrel chewing on the wires. Fortunately, they burned themselves out (lost contact) before more damage was done.
BlackenedModuleBacking-tiny.png
This particular home had extensive damage. The squirrel nest itself was left for a long time and the moisture it retained caused the roof to rot. There was a hole in the roof, beneath the nest.

[SunEagle]

Well, apparently that is penny wise and pound foolish. If 90% of electrical failures are caused by improper connections, those industries that do not provide the proper tools are just foolish and some would say dangerous.

The NEC and manufacturers provide the torque specs and it would be wise to comply.

I agree that some companies do not think about getting the correct tool for it's maintenance people or provide them enough funding to get their own "specialty" tools.

That was one of the reasons I pushed for a Thermal IR camera and developed the entire PM program around using it to find potential issues including poor terminations. We spent about $10,000 on equipment and training to set up the program we probably saved 10 times that in the first year by finding issues before they caused a fire and downtime.

[inetdog]

Well if you have been around sola rcrews are like landscapers, No Comprendo.

"Green side up!"

[Sunking]

But the real problem is untrained installers not using the correct techniques.

Well if you have been around sola rcrews are like landscapers, No Comprendo.

[DanS26]

From a "global" perspective, this is why I design my machines using components with spring terminals as much as possible, and require ferrules on stranded conductors. It isn't perfect, but at least you don't have to trust someone to use a torque wrench correctly.

sensij.....yes it's in the design....if electrical manufacturers built in the proper torque it could be significant.

If the connections "clicked" like your locking gas cap at the right torque, it would be a vast improvement.

[DanS26]

Most all Electricians are self employed contractors. Your typical Solar Contractor is not even an Electrical Contractor or knows much about electrical. It is a General Contractor, Home Improvement, Roofing Contractor, and some EC's milking the market with the free money as a side job until the bubble bust next year. They in turn hire roofers and an EC to do the work on Sub Contract basis. Solar City is a Prime Example.

High voltage connections on the roof and improperly torqued connections. Sounds like a fire to me!

So what does the NEC do....require arc fault detection. OK.

But the real problem is untrained installers not using the correct techniques.

[J.P.M.]

From a "global" perspective, this is why I design my machines using components with spring terminals as much as possible, and require ferrules on stranded conductors. It isn't perfect, but at least you don't have to trust someone to use a torque wrench correctly.

Understood. I was thinking more of any system where the failures were concentrated in a very lopsided and possibly identifiable way. Sort of like forensic system engineering.

[sensij]

Depending on frequency and gravity of the failures, if I was looking at a spot where a large %age of those failures seemed to be concentrated, I'd take a long, global look at it and see if I could figure out why.

From a "global" perspective, this is why I design my machines using components with spring terminals as much as possible, and require ferrules on stranded conductors. It isn't perfect, but at least you don't have to trust someone to use a torque wrench correctly.

[J.P.M.]

Well, apparently that is penny wise and pound foolish. If 90% of electrical failures are caused by improper connections, those industries that do not provide the proper tools are just foolish and some would say dangerous.

The NEC and manufacturers provide the torque specs and it would be wise to comply.

Depending on frequency and gravity of the failures, if I was looking at a spot where a large %age of those failures seemed to be concentrated, I'd take a long, global look at it and see if I could figure out why.

[Sunking]

Well, apparently that is penny wise and pound foolish. If 90% of electrical failures are caused by improper connections, those industries that do not provide the proper tools are just foolish and some would say dangerous.

They are called self employed contractors. Just about all electrical shops require employees to provide their own tools.

Yes most electrical fires are from poor connections. Connections cover a wider area than you think. A switch and relay are connectors with connection terminals.

[DanS26]

You forgot to mention that most industries don't provide a large tool budget for their electricians to purchase a torque wrench.

Contractors like to work fast and use what ever tool is in their belt. Mostly a big screwdriver.

Maintenance electricians are more concerned with getting Electrically Insulated hand tools to prevent a shock or electrocution. Not everyone can perform the work de-energized.

Well, apparently that is penny wise and pound foolish. If 90% of electrical failures are caused by improper connections, those industries that do not provide the proper tools are just foolish and some would say dangerous.

The NEC and manufacturers provide the torque specs and it would be wise to comply.

[Sunking]

You forgot to mention that most industries don't provide a large tool budget for their electricians to purchase a torque wrench.

Most all Electricians are self employed contractors. Your typical Solar Contractor is not even an Electrical Contractor or knows much about electrical. It is a General Contractor, Home Improvement, Roofing Contractor, and some EC's milking the market with the free money as a side job until the bubble bust next year. They in turn hire roofers and an EC to do the work on Sub Contract basis. Solar City is a Prime Example.

[sensij]

Ahh.....Found it:

http://ecmweb.com/contractor/do-you-have-calibrated-arm

Neat data, although 2/0 connections are pretty serious. I would hope that the accuracy is better on the conductors normally used in residential PV systems... say, 6 to 10 AWG, but have no idea if that is true.

[SunEagle]

Ahh.....Found it:

http://ecmweb.com/contractor/do-you-have-calibrated-arm

You forgot to mention that most industries don't provide a large tool budget for their electricians to purchase a torque wrench.

Contractors like to work fast and use what ever tool is in their belt. Mostly a big screwdriver.

Maintenance electricians are more concerned with getting Electrically Insulated hand tools to prevent a shock or electrocution. Not everyone can perform the work de-energized.

[inetdog]

Ahh.....Found it:

http://ecmweb.com/contractor/do-you-have-calibrated-arm

Very interesting, thank you!
A second question that would be interesting to ask electricians specifically is "what is the proper torque value for this component?"
A torque driver is of no particular benefit if you do not know what value you are trying for.