Solar panel fires!

[DanS26]

I read a study done with electricians on how well they could "feel" the right torque. I searched but could not find it, but what I remember is that the vast majority under-torgued and some over-torqued. The bottom line was very few hit the proper torque. This study was done with very experienced electricians.

Maybe someone could find it and post. I'd like to read it again.

Ahh.....Found it:

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

[DanS26]

I didn't use a torque wrench for this project. I certainly endorse them if available along with
the required torque specs and a qualified operator. They get used here on critical items like
engine assembly.

However, some of us who have been assembling things at home & work for 5 or 6 decades
have gotten quite able to detect the border between "pretty tight" and "in danger of stripping"
with a good right arm. The electrical stuff I put together was far more uniformly tight initially,
than when I checked it after a few seasons. Bruce Roe

I read a study done with electricians on how well they could "feel" the right torque. I searched but could not find it, but what I remember is that the vast majority under-torgued and some over-torqued. The bottom line was very few hit the proper torque. This study was done with very experienced electricians.

Maybe someone could find it and post. I'd like to read it again.

[Sunking]

I lump EV charging into this too, although there is probably less that can go wrong. Cars can charge at 6.6 kW, in the middle of the night when cold terminations will rapidly heat up... seems like higher risk than your average appliance.

Already been multiple EV fires while charging. Neil Young burnt down his garage and part of his house. Over a million in damage. Added a new meaning to Crosses Burning justice.

[sensij]

You completely glossed over MY point. All that stuff is dangerous too, but the total running time
is on the order of a dozen hours a year. The total risk is MULTIPLIED by the number of hours in
operation, THOUSANDS of hours for solar. AND secondarily, my stuff is closely supervised against
fire risk; solar practically never is.

Candles, give me a break. Bruce Roe

I lump EV charging into this too, although there is probably less that can go wrong. Cars can charge at 6.6 kW, in the middle of the night when cold terminations will rapidly heat up... seems like higher risk than your average appliance.

[bcroe]

My point was simple- solar does not bring extra danger compare to any other equipment. Mistakes happen everywhere and yes, it's an additional component but following this logic we should use candles. Oh sorry, fire hazard again . Some of the equipment you listed is probably more dangerous than solar, you just get used to it.

You completely glossed over MY point. All that stuff is dangerous too, but the total running time
is on the order of a dozen hours a year. The total risk is MULTIPLIED by the number of hours in
operation, THOUSANDS of hours for solar. AND secondarily, my stuff is closely supervised against
fire risk; solar practically never is.

Candles, give me a break. Bruce Roe

[bcroe]

Bruce, did you torque all connections to specifications?

Torque screwdriver or wrench is an electrician's best tool but sadly hardly anyone uses them.

I didn't use a torque wrench for this project. I certainly endorse them if available along with
the required torque specs and a qualified operator. They get used here on critical items like
engine assembly.

However, some of us who have been assembling things at home & work for 5 or 6 decades
have gotten quite able to detect the border between "pretty tight" and "in danger of stripping"
with a good right arm. The electrical stuff I put together was far more uniformly tight initially,
than when I checked it after a few seasons. Bruce Roe

[DanS26]

That was one of the first things I thought about, and one of many reasons I have a ground
mounted array hundreds of feet from any building. I am going to add this which just might
relate to some fires.

After some 22 months of service, I have decided to join the "TIGHTEN ALL CONNECTIONS
REGULARLY" school. I have been running 15 KW out every sunny day not just at solar noon,
but for many of the daylight hours. None of the wiring is approaching its absolute limit,
but at the end of sun it can definitely be felt to be warmer than the surroundings.

There are a couple inverters, DC and AC disconnect boxes, several AC breaker boxes, and a
DC combiner box. All the connections were initially checked by me. About a year ago a
circuit breaker failed, apparently from heat at one of the line terminals. This month a DC
screw connection to a disconnect switch (carrying 21A @ 360 VDC) burned out. The
problem was detected & repaired in a couple hours, but the issue is, why did it happen
at all?

As others have suggested, perhaps the constant heat/cool cycles at significant power can
work these connections loose. Loose enough, the resistance will rise and they burn out.
I undertook (in the dark of course) to check them ALL for tightness. Sure enough, the
tightness of screws after 1.5 years varied A LOT. Since all were done by the same person,
often many the same day, some had apparently loosened up. My conclusion is that
these all need to be rechecked annually, at least until they ALL show some settling to
stability.

So far, no issues with split bolt or soldered connections. Bruce Roe

Bruce, did you torque all connections to specifications?

Torque screwdriver or wrench is an electrician's best tool but sadly hardly anyone uses them.

[SunEagle]

My point was simple- solar does not bring extra danger compare to any other equipment. Mistakes happen everywhere and yes, it's an additional component but following this logic we should use candles. Oh sorry, fire hazard again . Some of the equipment you listed is probably more dangerous than solar, you just get used to it.

We are not saying to stay away from a solar pv system because they are dangerous. We are saying that due to their nature of being outside (wind & water intrusion) and with the possibility of being installed by less than professional people will increase the chances of a fire being started from an electrical issue.

Nothing is perfectly safe. Just how and where something is installed can change the potential % of a failure.

[max2k]

Unlike most consumer equipment, solar runs quite high power, using facilities not too far
from capacity, for long hours, cycling every day, with no one watching. I think that raises
the chances of a fault a huge amount, with more serious consequences.

I do run a welder, a car lift, some multi horse electric motors. But those have an extremely
light duty cycle, and I am generally right there at the time. The huge majority of my house
wiring is just sitting there for my convenience, doing next to nothing all the time. Bruce Roe

My point was simple- solar does not bring extra danger compare to any other equipment. Mistakes happen everywhere and yes, it's an additional component but following this logic we should use candles. Oh sorry, fire hazard again . Some of the equipment you listed is probably more dangerous than solar, you just get used to it.

[bcroe]

I remember back in 1970 there were > 1000 deaths per year from accidental electrocutions. A lot of people who died were found in a wet crawl space when they grabbed a water pipe that had been accidentally electrified which help drive the NEC to include GFI circuits in more areas around the home.

Another change (which seems pretty straight forward now) was back before the sixties most homes had receptacles with 2 wires. The ground wire was not included.

I can still remember, in the 50s asking an electrician what that new 3rd wire was for. Since
then I have changed out an awfully lot of outlets. My earlier experience with the 3rd wire, was
that it didn't make a reliable contact at all. Haven't checked for improvement lately. I much
prefer to rely on GFIs and double insulated appliances. Bruce Roe

[SunEagle]

All you gotta do is watch TV or read the news. The Holidays is a busy time for FD's.

The reason for electrical codes getting stricter and more expensive each cycle is a result of fires. For every electrical code on the books, and all future codes are in response and paid for in blood and damages caused by fires.

I bet most members here think GFCI circuits in wet areas is old as dirt and think nothing of it. Care to guess how many people like babies had to die to get them written into the codes. How many kids got burned,electrocuted, and fatally injured by wall sockets each year? Do you even know in 2008 you are now required to use TR receptacles aka Child Proof sockets as a result.Can you say 2400 children per year or injured or killed playing with electrical sockets. That is almost 3 times as many people that police shoot each year.

I remember back in 1970 there were > 1000 deaths per year from accidental electrocutions. A lot of people who died were found in a wet crawl space when they grabbed a water pipe that had been accidentally electrified which help drive the NEC to include GFI circuits in more areas around the home.

Another change (which seems pretty straight forward now) was back before the sixties most homes had receptacles with 2 wires. The ground wire was not included.

[bcroe]

I don't think solar creates any extra fire hazard compare to your conventional power wiring

Unlike most consumer equipment, solar runs quite high power, using facilities not too far
from capacity, for long hours, cycling every day, with no one watching. I think that raises
the chances of a fault a huge amount, with more serious consequences.

I do run a welder, a car lift, some multi horse electric motors. But those have an extremely
light duty cycle, and I am generally right there at the time. The huge majority of my house
wiring is just sitting there for my convenience, doing next to nothing all the time. Bruce Roe

[Sunking]

Your just being a pessimist.

Thank you someone has to do it and inject reality.

Of course this is not limited to solar pv installation, it could involve an outdoor spa, water pumping systems or decorative lighting (Christmas) systems that can put a strain on the wiring.

All you gotta do is watch TV or read the news. The Holidays is a busy time for FD's.

The reason for electrical codes getting stricter and more expensive each cycle is a result of fires. For every electrical code on the books, and all future codes are in response and paid for in blood and damages caused by fires.

I bet most members here think GFCI circuits in wet areas is old as dirt and think nothing of it. Care to guess how many people like babies had to die to get them written into the codes. How many kids got burned,electrocuted, and fatally injured by wall sockets each year? Do you even know in 2008 you are now required to use TR receptacles aka Child Proof sockets as a result.Can you say 2400 children per year or injured or killed playing with electrical sockets. That is almost 3 times as many people that police shoot each year.

[SunEagle]

I would have to strongly disagree with that statement and any statistician would disagree. Anytime you you buy an appliance, add a circuit, plug anything in you just increased your chances you fire risk. Couple that with the Solar Industry having very low experience levels, little training, human error, and lax electrical licensing requirements all add up to higher risk. Add to that most of the equipment is outside and exposed to the elements and you get the picture.

Your just being a pessimist.

But I have to agree with your logic.

Adding complexity to an electrical system using low experience workers raises the chances of electrical fires. Of course this is not limited to solar pv installation, it could involve an outdoor spa, water pumping systems or decorative lighting (Christmas) systems that can put a strain on the wiring.

[Sunking]

I don't think solar creates any extra fire hazard compare to your conventional power wiring:.

I would have to strongly disagree with that statement and any statistician would disagree. Anytime you you buy an appliance, add a circuit, plug anything in you just increased your chances you fire risk. Couple that with the Solar Industry having very low experience levels, little training, human error, and lax electrical licensing requirements all add up to higher risk. Add to that most of the equipment is outside and exposed to the elements and you get the picture.