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Overnight Open Thread »
March 06, 2010
AoS Ongoing Weekend Home Improvement Series™
Electricians behaving badly
OK, so you throw a switch, and hear something that sounds ominously like a fresh bowl of Rice Crispies snap crackling and popping and think there's maybe some grim shit going south in the wall conspiring to burn your crib down.
I just got done straightening one of those scary situations out for one of the neighbors.
In their case it was due to something commonly known as "backstabbing". On the really cheap residential grade switches and receptacles, there's usually a "feature" on the devices that allows for quick/easy(and bogus) attachment of #14 wire (commonly used on 15 amp circuits).
To backstab, all you do is strip the wire and poke it into a little hole and some internal spring fingers grab it and make the connection. It is quick, it is easy, it is UL and NEC legal for #14 wire, so an inspector is compelled to pass an installation that's done using backstabbing. However, backstabbing will also invariably FAIL over time.
Those little spring fingers get weak, the connection goes bad and starts to arc (that may be the ominous crackling noise you're hearing), or in some cases the wire falls right out the back of the device and you wind up with nothing.
In my neighbor's case, all I had to do to get their shit working again sans-drama, was eliminate the backstabs, loop the end of the wire and use the screws on the side of the device. Easy/cheap fix. If the original cretins installing the stuff had done it that way, the problem would never have developed and his wife wouldn't have been panicking about the joint burning down.
Moral of the story -- don't let your electrician backstab you.
A while ago backstabbing became prohibited on 20A circuits using #12 wire, so a newer joint shouldn't have a problem there. Older places built in the 1980's and mid-90's and earlier may still have backstabbed 20A circuits. Backstabbing can really cause problems on a dishwasher/disposal receptacle found under sinks. Those are often a split feed with a 220V circuit coming into them where one each half of the receptacle has 120V going to it with a shared neutral. If you see a 2-pole 20A breaker in your panel, you may have one of those type hookups.
Another neighbor had a fire in the box under his sink due to backstabbing on the dishwasher/disposal receptacle. That shit was scorched and burned up real good with smoke pouring out. 220V shorts make for nice toasty arcs.