Pic of melted lug

[electricmanscott]

I agree. Why take any chances with this? Just de-energize and replace the set-screw and/or lug. You can then torque to specs and never worry about it again.

I am not worried about it at all.

Maybe the pics don't show it well but ONLY the inside of the set screw is affected. It is most definitely melted. There are no other signs of melting on the lug or the wire.

As I mentioned, it is a pretty good bet that this panel came out of another building somewhere. My guess is that either on removal or new installation the wrench was inserted into the lug set crew and shorted. It did not hit the can as there are no signs of any blow outs. Same for all the wiring in the area of the lug.

This has been this way for ages and I left it as is.

 

[Jim W in Tampa]

Is another possable answer here. As indicated it was likely a used panel. Could it have been missing the screw and this screw we are seeing was simply a truck answer to finish the job ?

 

[K8MHZ]

Is another possable answer here. As indicated it was likely a used panel. Could it have been missing the screw and this screw we are seeing was simply a truck answer to finish the job ?

The owner is a commercial construction guru and his buddies "found" the panels on a job.

And they may or may not have been all in one piece at the time.

About the only prudent thing to actually do is to replace the bolt and that may not even help to do anything but alleviate stress from the burning question as to whether or not there is more damage than visible.

That is, of course, if it comes out without a fight.

 

[mcclary's electrical]

And they may or may not have been all in one piece at the time.

About the only prudent thing to actually do is to replace the bolt and that may not even help to do anything but alleviate stress from the burning question as to whether or not there is more damage than visible.That is, of course, if it comes out without a fight.

Scott doen't seem to be as worried about it

 

[electricmanscott]

Scott doen't seem to be as worried about it

I'm not at all.

Just look at that copper. Looks like new! This is a large all electric house with a fairly large load. If that lug was loose causing that melting on the lug the conductor would be fried.

 

[iwire]

Just look at that copper. Looks like new! This is a large all electric house with a fairly large load. If that lug was loose causing that melting on the lug the conductor would be fried.

I agree .......... but considering the lack of work I might ofer to fix it.

 

[George Stolz]

Why not simply replace it.

It would give Scott a chance to get rid of that obscure lug for that 30 year old panel he's been carrying around in his pocket all these years. You would think it would have occurred to him that it's time had come.

 

[wptski]

I have very limited electrical knowledge but I always thought the bolt, setscrew, etc. was to make mechanical contact between two conductors but not be a conductor of current itself. If the setscrew is indeed melted, it carried current which it shouldn't for some reason.

 

[iwire]

If the setscrew is indeed melted, it carried current which it shouldn't for some reason.

That is exactly why most of us figure that the person had an Allen wrench in the screw while it was live and the other end of the Allen wrench hit something grounded. The current appears to have been flowing through the Allen wrench to the inside of the Allen screw. A very unusual situation.

 

[Jim W in Tampa]

Even with a new screw part of the current will be going threw this screw and that is normal.
Was his call to replace or not based on what he saw. The only reason it likely was melted was from what looks like an accidental short while tightening it and that seems not to been part of this install. Do hope who ever did this lived as it would been one hell of an arc.

 

[wptski]

Even with a new screw part of the current will be going threw this screw and that is normal.
Was his call to replace or not based on what he saw. The only reason it likely was melted was from what looks like an accidental short while tightening it and that seems not to been part of this install. Do hope who ever did this lived as it would been one hell of an arc.

Part of the current? Every termination is a parallel path?

 

[Jim W in Tampa]

Part of the current? Every termination is a parallel path?

Yes all metal parts are part of the conductor and all are in paralel like it or not

 

[K8MHZ]

Yes all metal parts are part of the conductor and all are in paralel like it or not

And series at the same time!

 

[electricmanscott]

This call was to address home inspection report issues. The goal was to address as cheaply as possible. The lug will remain. Maybe until the next home inspection.

 

[Jim W in Tampa]

Just gotta love them HI guys. They know just enough to cost the customer the price of an electrician to do what they were paid for.

 

[dcspector]

The Home Inspector was simply documenting as would anyone. I personally see this all the time. As an Inspector simply document what you see, compile a report and be done with it.

 

[mcclary's electrical]

I'm not at all.

Just look at that copper. Looks like new! This is a large all electric house with a fairly large load. If that lug was loose causing that melting on the lug the conductor would be fried.

Just so you know Scott, that was an observation, not a judgement.

I think I would have done the same thing

 

[wptski]

Yes all metal parts are part of the conductor and all are in paralel like it or not

Not always! Had a machine from Magneform, second picture on that page of the actual part, a automotive drive shaft.

It had a thick copper alloy plate wth a series of cables clamped with a bar held with socket heard bolts. The tapped holes were helicoiled from the factory. They had a problem with helicoils breaking up in pieces as I remember.

Machine would blow up frequently and somewhere along the line, somebody left out special insulators for the bolts. Current carried through the bolts to the helicoils and damaged them.

This was some machine too! Anything that was a bit loose like a simple cover would create arcing.

 

[AV ELECTRIC]

If the Lug can not be loosened or tightened you cant know what your torque is you cant provide proper maintenance with the damaged lug now or in the future. It should be replaced .

 

[electricmanscott]

If the Lug can not be loosened or tightened you cant know what your torque is you cant provide proper maintenance with the damaged lug now or in the future. It should be replaced .

What maintenance does a lug require?