Originally Posted By: phinsperger This post was automatically imported from our archived forum.
Possiblly one of the following
1) the load is severly unbalanced between the two legs and that the greater load is on the bottom leg resulting in warmer temp thus not coroding like the othe other leg.
2) There is water entering the cable at the other end (meter box) and coming down by gravity/capillary action
3) Lower leg only replaced (maybe mechanically damaged ot what have you)
Originally Posted By: rmoore This post was automatically imported from our archived forum.
Dennis…
Genuine request for education:
If the oxidization was being caused by heat from a loose connection wouldn't the top few strands be disclolored also? Or at least as much?
There is what appears to be a single spot of oxide on the lower conductor (a drip?) and then there is what looks like discoloration in the space between and behind the SECs. What's going on there?
-- Richard Moore
Rest Assured Inspection Services
Seattle, WA
www.rainspect.com
Originally Posted By: Greg Fretwell This post was automatically imported from our archived forum.
The heat starts at the point of worst connection and I bet that was right under the screw. The parts jammed into the lug will tend to stay put but if the screw loosens a little that will be the weak spot. Look at the bad conductors again.
Originally Posted By: rmoore This post was automatically imported from our archived forum.
OK…you’ve got me half convinced on the loose connection theory. How about… “Discoloration of one SEC indicative of a loose connection, moisture intrusion, or possibly other problems. Recommend investigation and repair by a licensed Sparky”. Should cover it!
Originally Posted By: roconnor This post was automatically imported from our archived forum.
Just throwing this out there, but that kinda looks like corrosion … possibly older dissimilar metals with missing/insufficient anti-oxidant compound on the top wire?
– Robert O’Connor, PE
Eagle Engineering ?
Eagle Eye Inspections ?
NACHI Education Committee
I am absolutely amazed sometimes by how much thought goes into doing things wrong
Originally Posted By: rmoore This post was automatically imported from our archived forum.
Let me toss this into the mix. Back last year, after finding the thick granular corrosion on a burnt conductor (pictured below), I did a little research. Turns out there are three different types of copper oxide and what you get depends a lot on how hot the copper gets. Below 150C, Cu2O forms. This is the “protective” patina on the Statue of Liberty and is the result of lower heats and/or moisture. Above 200C CuO can form. This is “significant” corrosion rather than a patina, and probably what is in my photo. Between 150 and 200C? There’s a third complex oxide I don’t have the letters for.
-- Richard Moore
Rest Assured Inspection Services
Seattle, WA
www.rainspect.com
