[RE-wrenches] burnt wire

[Maverick Brown]

Looks like the wire was not completely seated in the back of the terminal before the set screw was tightened, the set screw grabbed a strand or two and felt as though it was tight, etc. or the screw wasn’t tightened enough. The resistive connection led to a lot of heat causing the insulation to burn. I prefer using ferrules on those big terminals when using smaller than maximum size wire. 

Maverick Brown
Off-Grid Solar Commander since 2006
Maverick Solar Enterprises, Inc.
 • Solar Commander Remote Power
 • SunFlow Systems Cathodic Protection 
maverick at mavericksolar.com
512-460-9825


> On Jan 31, 2022, at 7:51 PM, Dave Tedeyan <dave at sungineersolar.com> wrote:
> 
> 
> Hi All,
> 
> I was troubleshooting a Schneider system today (not my install, so I don't know the history) and came across a wire where the insulation actually burnt off. See the attached photo. I have never seen anything like it. Does anyone know how this could happen? It was a Conext MPPT 80 600 charge controller going to a 100A breaker, with what appears to be #2 CU wire. This is in a heated shed, and there is no evidence of water leakage. The charge controller was still working just fine. And it was only that last 6" or so of the wire, the rest of it appeared to be fine.
> 
> Cheers,
> Dave
>  
> -- 
> 	
> Dave Tedeyan, P.E.
> Owner | Sungineer Solar
> p: he | him | his
> a: 1653 Slaterville Rd. | Ithaca, NY 14850
> w: www.sungineersolar.com
> c: (607) 288-2898
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