Forgot to tighten lug

[MarkSolar]

I had to reconfigure my system and found one of the wires in this disconnect totally smoked. I realized I had forgotten to tighten it about 4 years ago when I put this together. I think what happened was I planned to add a terminating ferrule to that wire so I left it loose. Then I forgot to come back and put the ferrule on so it stayed loose and got hot enough to totally melt the insulation and corrode the lug.

 

[LakeHouse]

Thanks for sharing, glad that didn't turn out worse.
A suggestion for you and others: Get a FLIR camera (cheap ones from Amazon are about $100) and have a look at all of your connections when the system is working its hardest: charging in full sun for the generation side, running a large load on the ac side, etc.. Something like this almost certainly would have been super obvious.

 

[robbob2112]

OOOOPSS..

could have been worse ....

I went out and retorqued all the wires on a sub panel I put in a number of years back a few months ago and was amazed how loose some of the lugs were..... I was lucky most of the wires were to things seldom used. Went through the whole main panel and a lot of those had a 1/2 turn to tighten.

 

[MarkSolar]

Thanks for sharing, glad that didn't turn out worse.
A suggestion for you and others: Get a FLIR camera (cheap ones from Amazon are about $100) and have a look at all of your connections when the system is working its hardest: charging in full sun for the generation side, running a large load on the ac side, etc.. Something like this almost certainly would have been super obvious.

I'm going to get one of those, I have been using an infrared thermometer. The "problem" with these Square D disconnects is you can't turn them on with the door open, which is a great safety feature but makes it hard to measure the temp. I guess I can turn off that inverter then turn off the disconnect and hurry up with the camera before it can cool down.

 

[robbob2112]

I'm going to get one of those, I have been using an infrared thermometer. The "problem" with these Square D disconnects is you can't turn them on with the door open, which is a great safety feature but makes it hard to measure the temp. I guess I can turn off that inverter then turn off the disconnect and hurry up with the camera before it can cool down.

Usually it is just a spring loaded thing blocking the lever so you can turn it on pretty easy.

 

[MarkSolar]

I went out and retorqued all the wires on a sub panel I put in a number of years back a few months ago and was amazed how loose some of the lugs were..... I was lucky most of the wires were to things seldom used. Went through the whole main panel and a lot of those had a 1/2 turn to tighten.

I had the same thing happen when I did my recent upgrade. I installed a line side tap so I checked all the lugs, including the ones in the meter can that are generally not accessible. They were all loose, some were so loose it made me wonder if they were ever tight. I've started using a torque wrench. I used to think I could estimate pretty well but I tested myself and I'm always under torqued by 30-50%.

 

[robbob2112]

I had the same thing happen when I did my recent upgrade. I installed a line side tap so I checked all the lugs, including the ones in the meter can that are generally not accessible. They were all loose, some were so loose it made me wonder if they were ever tight. I've started using a torque wrench. I used to think I could estimate pretty well but I tested myself and I'm always under torqued by 30-50%.

Me too... my old standard of 3 squeaks just doesn't work unless it is on and car.

 

[MarkSolar]

Usually it is just a spring loaded thing blocking the lever so you can turn it on pretty easy.

I'll have to look at how it works. I know the door won't open if the switch is on, and once it's off I never had a reason to try to turn it on with the door open. But now I'm going to check everything every year or so.

 

[Tsolar]

You can turn them on with the door open. Most larger disconnects have a catch inside that wont let you OPEN the door with the switch on. But many of them have a little "knob" on the side that allows you to "lift" the safety latch and open the door, without turning the switch off. SqD switches have a little knob with a slot thru it, behind/above the operating handle, you can use a screwdriver or pocket knife in the slot and rotate this to lift the latch off the door catch and open the switch, if it seems hard to turn, turn the other way, or push some pressure on the door to to relieve tension on the latch, they usually turn pretty easy if everything is correct, so dont force it.

 

[Daddy Tanuki]

dont feel bad I did the same thing about 6 or 8 months ago... posted it in up in smoke as well. glad you caught it. I did it when rearranging wires and leads to neaten up my install, I was inserting to measure for exact lengths. and I got interrupted and forgot to put a ferule on as well as tighten... found out a week later upon return to Kendiana to see smoke and hear crackling coming form my midnite solar E panel...

 

[Chispas]

I've started using a torque wrench.

What brand do you have & how do you use it for slotted or Philips screws ? I was thinking I could just put a Phillips or slotted bit into a 6 mm socket. Then I'm thinking about the play or backlash & how it could affect the accuracy of the torque wrench.

 

[MarkSolar]

What brand do you have & how do you use it for slotted or Philips screws ? I was thinking I could just put a Phillips or slotted bit into a 6 mm socket. Then I'm thinking about the play or backlash & how it could affect the accuracy of the torque wrench.

I've collected enough torque wrenches over the years to start my own museum. I prefer using digital torque heads now, that allows me to use a ratchet wrench that I'm familiar with and use every day rather than some clunky torque handle that I only use once a week. I use a socket to hex drive adapter for screwdriver bits, although I don't recall ever using that on anything electrical. All the electrical things I've seen either use square drive, Allen drive, or some kind of regular bolt head.

 

[Chispas]

I prefer using digital torque heads now,

Something I didn't know existed, LOL. I'm still with my 1/2 inch fully analogue torque wrench that I've had for years.

 

[robbob2112]

Something I didn't know existed, LOL. I'm still with my 1/2 inch fully analogue torque wrench that I've had for years.

I bought a new torque wrench and torque screwdriver at home depot when I started playing with batteries. This was because my beam torque wrench from the 1960s and the screw handle wrench from the 80s didn't go low enough.

The digital type that beeps is much simpler to use and it warns you when you are getting close.

If I had it to do over I would buy a torque head.

 

[v_green57]

Do what the big SES mgfrs. (Siemens, Square D, etc.) do:

Put a slash mark across each nut, bolt, etc. with a Sharpie as you tighten them.

 

[Daddy Tanuki]

ahhh I am a tool slut... i have a 1/4" snap on for things like this... but then I always buy tools one time...at 68 my collection is yugely beautiful

 

[robbob2112]

ahhh I am a tool slut... i have a 1/4" snap on for things like this... but then I always buy tools one time...at 68 my collection is yugely beautiful

Does your wife know about this? Or does she catch you out in the shed making out with a 6ft cheater bar?

 

[Brucey]

Spreader bar?