PSA: Electrical Wiring

[alfsauve]

Older son just bought a new washer/dryer and it came with a 4 prong plug.  Of course his town home only has 3 prong sockets, so the store sold him a 3 prong replacement cord.  They gave him instructions on how to swap them out and he distinctly remembers they said make sure the screws are tight. 

W R O N G


#1 Son isn't the overly technical type.  Fortunately, he called me to inspect his installation.  The first thing I did was wiggle the wires, AND THEY MOVED.  The screws were tight, but the wires weren't.  (Too long an explanation of how that happened but it can.)  This is a serious fire hazard as wires that aren't secure will arc and arcing comes with a tremendous amount of heat.  Hot enough to melt steel.   Below is a picture of what's left of an outlet that had an unsecured neutral.

So what should the store clerk instructions have been?

TIGHTEN THE SCREWS UNTIL THE WIRES ARE TIGHT.

A minor wording difference but it makes all the difference.  Yes the screws will be tight as well, but just remember always check the wires.  It's one of those cases where A implies B but B does not imply A.

[Rastus]

Exactly. 

I had a similar experience but with a 50 AMP 220/240V RV hookup that a contractor had installed.  Power on...power off...shake it and it's on...shake it and it's off.  Actually, it wasn't power on/off it was a leg that dropped out.

[alfsauve]

I guess instinctively I always check the wires.  It never occurred to me until now that not everyone understands that. 

I also instinctively  check trailer tongues by trying to yank them off the hitch.  Maybe Im just not a very trusting guy.