Nothing to do with heating

Harvey Ramer

This summer I got called to a regular customer of mine. The complaint was that every time Sparky, the red haired service manager, got mad and went stomping off to the shop in a huff slamming doors as he went, the breaker would trip off the lights in the parts room. After several hours of tracing buried wires and poking my video scope into wall cavities, I found this buried in the wall.



It was resting directly on the door header which is why it tripped when the door slammed.

Breakers trip for a reason.

DanHolohan

Which is why you will always be worth hiring.

Harvey Ramer

Thanks for the nice words Dan.

Abracadabra

Wow... just wow....

Was the door (and header) a later addition? Just wondering why in the world they'd do that.

Gordy

Nice detective work Harvey. Did the conduit fall down, or what? The store must have run out of conduit, and or junction boxes.

Harvey Ramer

It's been like that for 40 years I suppose. So I have no idea who was thinking what. Must have been part timers or summer help that did it.

Pretty scary stuff.

KC_Jones

I see and here this stuff then I wonder, how bad does it have to be to start an electrical fire? It's scary.

Harvey Ramer

Well, a spark won't usually ignite standard building materials unless it is something highly volatile. Typically, it will be the heat. For example, a wood like pine has a spontaneous combustion temp of around 575 degrees. Loose connections causing overheating are more often than not the catalyst for fires, rather than dead shorts.

KC_Jones

I have a family member that lost a house to an electrical fire, it's actually crazy how it can happen. His was due to an error made 10 years earlier when the house was built. Someone nicked a 220 line with a staple just enough to cause a weak point. Expansion and contraction over the years from the heat in the wire due to load made it worse and worse. One day when no one was home it finally ignited the main beam in the basement. Burned the house completely out when no one was home....small miracles.

ratio

I was never a fan of arc-fault breakers, but I saw first hand the kind of problem they find. Had to have been a manufacturing flaw in the insulation on a piece of MC, arced over just enough to char the 2x over the course of the weekend. No staple within several feet in any direction. No damage to the cladding save for a tiny hole melted in it, about the size of the head of a pin. A tiny pit in the copper, had to have been the hot wire, took me five minutes to find it looking over the piece I cut out, about two feet long.

Jamie Hall

I'd love to have arc fault breakers in this place. Anyone want to fund the conversion? (at least I have fuses which can only be replace with the correct size...). A lot of the fixture wiring is fabric over rubber insulation, and getting on for a century old. I have to -- and do -- keep an eye on it, and check the fixtures for faults from time to time.

Harvey's right, though -- it's the heat, not an arc (unless it's a real big one -- which will usually blow a fuse), that usually causes the damage. There are any number of houses which still have aluminium wiring; they can overheat remarkably easily if the right sort of connectors aren't used.

SlamDunk

My company gives me access to tools I couldn't afford on my own. Every year, I thermal scan every outlet, conduit, junction box and wall. Not because I like to play with toys but because I'm paranoid for just the reason KC_Jones mentioned.

My favorite pizza joint had to shut down for a week because of an electrical fire to wires outside their brick and stucco building that have been untouched for years. Poof!

KC_Jones

My neighbor has standard romex run on the exterior of their house for some circuit someone wanted to add years ago. The sun is destroying that insulation and I am pretty sure it's only a matter of time before something happens. It's a brick house so fire (hopefully) isn't a concern. I wanted to touch the wire once, but I seriously think the insulation would just fall off at this point. People do strange things with electricity. Oh and I should add it's on an alley where people walk and at least 20' of the wire is well within reach of even children.