Hot phase

[Fanin6565]

New construction, 600 amp main breaker removed by electrical contractor to be bench tested by testing company and replaced by same electrical contractor in 2016.
Also as part of the project infrared inspection was performed in 2019, no issues were found.
Loads on panel; basement sump pumps, exhaust fans, FCU, two transformers (maybe 100 amps max).
"A-Phase" shows gaps between breaker line side lug to bus hardware and bolt/washer to breaker lug.
I spot checked temperature upon finding loose connection and recorded temperature of 245F, molten metal at loose connection.
"B & C"- Phase" do not show any issues.
Contractor says this problem was not the cause of poor workmanship by their doing; your thoughts?

 

[Hv&Lv]

The work was done in 2016, 3 years later (2019) an IR scan was done (hopefully with as many loads as possible running for a while), and now (2020) you did another IR scan and found this problem?

I say the contractor was covered by the 2019 IR scan as no problems had shown up in three years.

 

[xformer]

Standard contract language most of the includes just a 1 yr warranty.

 

[ptonsparky]

Too late.

 

[WasGSOHM]

temperature of 245F, molten metal at loose connection.

I never bought an IR meter but I'd think molten metal should read more than that.

Improperly torqued connections can still pass an IR scan? I'm sure somebody has a graph of contact resistance vs. lb-inches of torque.