Outlet brainteaser

[Audiopile]

Friday I experienced a new one on me I haven't seen before concerning a problem duplex outlet. Fixing the outlet is not really within my pay scale... but it's got me bugged that I'm at a loss to explain it to myself the "why" of how it's doing what it's doing... a bit of a brain teaser (for me anyway).

 

Here's the situation as near as I can determine: It's a standard 117v 15a duplex outlet, wired up in a quadbox along-side a light switch. The light switch is one of 2ea. two-way switches operating a bank of fluorescent lights in a farm shop (read that "the Friday night venue"). The bank of fluorescent lights seemingly function normally via the light switches; however, the duplex outlet is only energized when the switch in the same quadbox is in the "off" position (fluorescent lights off). Also, when the outlet is energized, it reads 117v across the neutral and load when unloaded, but the voltage sags considerably (drops 30 volts) with just a few amps of draw (tested with sheep shear clippers that were close at-hand at the time). And the ground lug for the outlet is "not wired" (no ground wire present in the quadbox).

 

The 60 yo. farmer's son of the farmer who wired it up 30 years ago was on-hand... and admitted that outlet has been messed up from day one when his dad wired it up... and added: "I've always wondered what was up with that?" I was at a loss to offer an explanation.

 

I did take the cover plate off the combo outlet & switch and had a quick look at the wiring in the quadbox... discovered there's only 3 wires wired to that quadbox... and from what I know, that's about 2 wires shy of what it would take to properly wire in a duplex outlet and one of the two-way switches... at a minimum what would be needed would be a ground, a neutral, one live conductor, and the L1 and L2 conductors running between the two switches.

 

I put the cover plate back on and said: "Don't use that outlet." But it's got me bugged why the symptoms are what they seemingly are.

[Dogoth]

Two way switches always confuse me (I have to draw out a diagram every time to make sure I can make it work). There's no reason they can't share a neutral (well maybe code) but the voltage drop is certainly a concern (14 ga with about a >500' run?). I'm guessing this box is not at the "feed (home run)" side of the 2 way but rather at the end of the line? That means that at the very least you'd need to run an "always hot" split off from the feed side to energize this duplex. I dunno but with that much voltage drop, short (pun intended) of a dedicated circuit from the breaker box, I'd just leave the "Don't use that outlet." rule in place anyway.

 

Just my uninformed .02

[fdew]

There are at least 3 ways to wire a three way switch (two switches for one load) that actually work. Two of them meet code most places.

 

One of them will allow a switch and a outlet at the far (Non powered fed) end using just 3 wires (plus a safety ground)

http://www.electriciantalk.com/f2/three-way-switching-standard-coast-carter-2229/ But that one hasn't met code for many years.

 

BUT you have something wrong. I suspect that when the switch next to the outlet is off the hot side of the outlet is connected to one side of the lights and the other side of the lights are connected to the hot. Plugging something into the outlet puts that something in series with the lights, therefor the quick voltage drop) turning on the lights connects the neutral wire to the lights and puts neutral on both sides of the outlet.

 

In this case a number of wrongs don't make a right but they do turn on the light.

 

I would remove the outlet. Even better would be to get it wired correctly.

 

[srp72ee]

I'll bet if you plugged a shop vac or circular saw into the outlet and turned it on, the lights would come on. Just guessing the voltage drop your seeing is through the light fixtures themselves.