From Today's Inspection

Name the obvious issues, and see if you recognize some of the less obvious issues…






Zinnsco & aluminum wire…
and all that comes with it…

Well, that does sum it up nicely :wink:

arcing at the breaker connection (pic 3)…
arcing and melting of the wire nut (pic 4)… is that the neutral connection?

First picture, appears to be oversized conductors cut to fit the breaker, difficult to be sure
Second picture solid aluminum conductors, excessive conductor exposed #2 and 3
Third picture ZINSCO = Kiss of death, corrosion maybe arcing?
Fourth picture excessive heat in wire nut, something is going on there

Yes, neutral. My guess is that there is no anti-oxidant paste in the pigtail (from AL to CU) which caused the heat build-up in the wire nut. I don’t believe these wire-nuts are rated for that connection anyway.

The breaker happens to be the 125 service breaker and it has almost completed its “fusion” to the bus bar :smiley:

Would you call out that the strands on what appears to be the SEC were nicked pretty deep? Or the insulation cut back too far? Were the AL wires loose on the breakers or was the insulation cut that far back on all of them?

Jeff, do you take any thermal images of these to show the heat/connection issues?

That would make a nice pic…

Those were at the AC circuit. I will call out nicked wires if they are severe, but I didn’t think it was warranted here. Same with the insulation. I didn’t think the missing insulation warranted a call-out at this degree. The wires were good and tight.

I do. This particular house was unoccupied. No significant heat “anomalies” developed in the short time I was there. In fact (surprisingly enough), even the voltage-drop measurements were unusually low.

The only indicators of poor connections (other than the obvious visible indications) were at the grounding conductors. Many of the receptacles measured near 2 ohms of impedance on their egc’s.

I see the aluminum wire.
I see several skinned back to far ??? Questionable.
In pic. #3 is there arcing in there back top side of the breaker on the bus. #4 is obvious. Its plain arc fault. Is this a paste problem I read about?

even the voltage-drop measurements were unusually low.
Some one point me to doing this testing please. I have read a bit about doing drop testing.
Links please.

You can start here then go


Thanks Mr.Mallarkey

I’m curious, what do you guys do with the results you get from voltage drop testing?

[FONT=@Arial Unicode MS][size=3]National Electric Code 110.12 Internal parts of electrical equipment, including bus bars, wiring terminals, insulators and other surfaces, shall not be damaged or contaminated by foreign materials such as paint, plaster, cleaners or abrasives, and corrosive residues. There shall not be any damaged parts that might adversely affect safe operation or mechanical strength of the equipment such as parts that are broken; bent; cut; deteriorated by corrosion, chemical action, or overheating. Foreign debris shall be removed from equipment.

Simply provide the information. When it’s excessive (10% or higher at multiple locations), I will recommend evaluation.

So with a VD that high are you looking for a poor connection or is 10% just a standard that inspectors use? The NEC is silent on the issue (unless you’re installing a fire pump) so I was just wondering how you apply this information.

That’s my own “guideline” and it fluctuates. Most inspectors don’t measure voltage drop. I use voltage drop measurements as an indicator for many things, but a “poor connection” is certainly a consideration.

As I’m sure you know, excessive VD indicates high resistance within the circuit. This resistance can be caused by a number of things, so it really depends on what I’m looking at, and/or what I’m looking for.

For instance, in a home with AL branch circuit wiring, measuring VD can help to determine the integrity of the connections at the pigtails and/or receptacles. I use my findings to help determine my written recommendations.

The NEC recognizes voltage drop as an “efficiency issue,” but makes no comment as to the cause (other than conductor length) or effects.

Good tool to buy Mr.Pope ?