e57
Senior Member
- Location
- San Francisco, CA
Alright this is some of my work.... Back from the holidays and I get this one spung on me.... I'm sticking the neck out real far here so play nice, I just want to know what happened, and looking for a little help explaining this to myself. Before you look any further this install is only say 3-4 months old - yet looks like it has been developing over years - really rapid deteriation. (Also I did not take the pic's - as I was off - and am also wondering some more about the conditions here myself. So bear with me...)
Pic below is a box outdoors that feeds ~40+' of RMC up hill on a grade above this point, and obviously drained into the box with the finger tight seal on the bottom that I "thought" would drain what little water I "thought" would possibly make it here - but seems to sealed itself with corrossion... I will also say that I knew the conduit run would pick up a 'bit' of water (But not this much) so the conduit goes down below this box, where I figured it would drain at fittings - then back up and over and down to this box. (which is semi-protected on the side of the building) And yes it is fed with NM, as I did not want to drian into the house - kill me.... It is also sealed pretty well with silicone in the back...
Note the amount of corrossion..... 3-4 months... Paint removed????
There is now a nice hole in the bottom of the box from what I understand.....
Sure - water in a box - what else is new.... The next part of this is the worrisome part. Almost 18 years at this and nothing like this have ever happened to me - and I DO NOT want it to happen again.... The NM feeding the box shown above goes up slighlty, then back down into the crawl space below where this happened. There wasn't much evidence of water here - but obviously so do to the green corrosion???? But it is possible that water capileried up then back down ~2' into the box where this short obviously occured. It's possible there was a knick in the isulation here - but you can't tell as there isn't much left....
Apparently the breaker tripped, and was reset - who knows possible a few times before they called. Also there has not been much rain untill recently at which point it DUMPED hard off and on for a few days - 3 storms in a row.
Not sure if or how this was corrected yet....
Any ideas????? (other than I need a desk job.)
IMPO the splices in the first box became submerged cooking the NM and causing some sort of electrolitic reaction to the box finish - portions of the NM which may have been cooled by water drawn in by the craft paper, and the eventual short occured at the second box closer to the source as soon as it wasn't cooled by water. Either way I'm changing a few bad habits and not taking drainage so much for granted.
Pic below is a box outdoors that feeds ~40+' of RMC up hill on a grade above this point, and obviously drained into the box with the finger tight seal on the bottom that I "thought" would drain what little water I "thought" would possibly make it here - but seems to sealed itself with corrossion... I will also say that I knew the conduit run would pick up a 'bit' of water (But not this much) so the conduit goes down below this box, where I figured it would drain at fittings - then back up and over and down to this box. (which is semi-protected on the side of the building) And yes it is fed with NM, as I did not want to drian into the house - kill me.... It is also sealed pretty well with silicone in the back...
Note the amount of corrossion..... 3-4 months... Paint removed????
There is now a nice hole in the bottom of the box from what I understand.....
Sure - water in a box - what else is new.... The next part of this is the worrisome part. Almost 18 years at this and nothing like this have ever happened to me - and I DO NOT want it to happen again.... The NM feeding the box shown above goes up slighlty, then back down into the crawl space below where this happened. There wasn't much evidence of water here - but obviously so do to the green corrosion???? But it is possible that water capileried up then back down ~2' into the box where this short obviously occured. It's possible there was a knick in the isulation here - but you can't tell as there isn't much left....
Apparently the breaker tripped, and was reset - who knows possible a few times before they called. Also there has not been much rain untill recently at which point it DUMPED hard off and on for a few days - 3 storms in a row.
Not sure if or how this was corrected yet....
Any ideas????? (other than I need a desk job.)
IMPO the splices in the first box became submerged cooking the NM and causing some sort of electrolitic reaction to the box finish - portions of the NM which may have been cooled by water drawn in by the craft paper, and the eventual short occured at the second box closer to the source as soon as it wasn't cooled by water. Either way I'm changing a few bad habits and not taking drainage so much for granted.
