MikeD wrote:TimLee: The root cause of the overheating was attributed to an over-torqued termination screw whose threads (or perhaps that of the screw receiver) were stripped, i.e. it no longer applied sufficient contact force between the wire (possibly with a crimped-on ring connector connector?) and this now defective termination screw. I don't see that this means the terminations block used was inadequate or defective. Am I missing something?
If I had such a device that overheated at a termination (and I didn't use my small torque wrench when I installed it), would it be fair for me to conclude the device was clearly at fault?
But it was the factory screw that was grossly loose.
I tend to believe Ingineer's evaluation that the terminal block design was inadequate for the service.
I think replacement with a well designed termination block is prudent and looking for information on the right choice.
Ingineer wrote:... it was Blink's engineering that specified a crappy low-cost terminal block. It's a marginal part for 20A, let alone 30A! On top of that, it was not installed correctly.
Several people personally inspected Berman's unit, I was one of them. One of the factory screws was not very tight, and the middle one was loose enough you could actually see a gap in-between the pressure plate and the conductor. I'm not even sure it was tightened at all. I think this is what started it down a path of overheating. The overheating looks like it eventually carbonized the plastic and then an arc-over event occurred on the input side. ...
Use of torque measuring driver is probably a good idea.
But I have observed quite a few electricians through my 45 years being involved in electrical work and have never seen one used.