Good Morning,

I recently moved into a new home. In the garage is a storage closet, where I was hoping to run some electricity for lights and a little workshop. Present in this closet when I moved in was some uncapped wiring running down from the ceiling, not connected to anything (I was shocked that this hadn't gotten called out in my pre-sale home inspection, because danger, but I digress.) The breaker box is in the living space above the garage, so I believe that this wiring comes straight down from the breaker box. It appears to be standard, 3 wire wiring. So, I identified which circuit breaker it was connected to, shut it off, and installed a standard outlet. FYI, because I"m not sure if it makes a difference, the breaker is one of those cheater breakers with two 15 amp breakers in one space/slot in the box. Plugged my fluorescent shop light into the bottom receptacle, turned it on and everything appeared to be working well.

A few days later, though, I plugged a brand new box fan into the top receptacle of the outlet. When I turned it on, I noticed funny smell, but thought maybe it was just manufacturing dust or lubricating oil from the fan burning off on the first use. But after just 2-3 minutes, the fan completely died. I assumed I had gotten a bum fan, and went and got an old one from the house. Plugged it in, turned it on and the exact same thing happened. So now I'm thinking there is something about this outlet that is burning out my fans.

Is it possible that this is actually a 240 line? I can't understand why my shop lights would continue to work if the outlet was pulling too much power. Wouldn't they burn up/out too? Besides, this is three wire wiring, and isn't 240 4 wire? How would I check the voltage to the line? I do have an analog multimeter, but am not very adept at using it for anything other than seeing if there is power flowing to an outlet.

 

You need to check the wiring with a volt meter. Switch your meter to the AC range that is next higher than 240 (your meter may say 250 or 500). Then make sure the probes are plugged into the correct spot on your meter for testing AC current. Then put one probe into each slot of the outlet. The needle will rise and you need to look at the corresponding scale to read the voltage.

It is possible that the wire was not connected to the breaker you thought. It's also possible that the wiring is totally wrong and not to any code so you need to proceed with caution and check everything.

 

Just want to emphasize this point - while 120 volt circuits can kill, their shock usually just hurts. If this truly is a 240 volt circuit, the risk of harm goes up quite a bit.

 

No. What you are calling "3 wire" is really 2-conductot cable. Both 120 and 240 use 2-conductor cable. On 240 the white wire is supposed to be remarked black or red (or any color but gray or green) but often it isn't. What you are calling a "4 wire" is actually a 3-conductor 120/240 feed.

Some fluorescent and LED lights have a voltage range of 120-277v.

 

Do you have a GE brand panel? Can you post a picture of the breaker as it is installed, preferably with the panel cover removed if you're comfortable doing so.

 

Thanks for the input, everyone.

Guess I should leave the electrical work to the pros or at least not make assumptions. I tested the outlet/line when I got home last night and it is indeed a 240 line. Not only that, but the breaker that I THOUGHT controlled the line only controlled 1/2 of it. Upon testing with the breaker off, 1/2 of the outlet was still hot. I'm lucky I didn't burn my house down or electrocute myself.

With my wife, my multimeter and Pilot Dane's advice on how to use my multimeter to measure the voltage, I was able to track down the breakers to shut the whole line off. One side of the outlet/one wire of the line seems to indeed be controlled by a cheater breaker and the other seems to be controlled by a double breaker. This seems really weird to me, but I did confirm with the multimeter that this killed the line.

There are two rooms above my garage, a living area and a bedroom. The living area has an electric baseboard heater with a separate wall mounted thermostat/controller. The bedroom has the controller for the electric heater, but no actual heater. It appears that what this line is actually intended for is the electric heat that was supposed to be installed in the bedroom over the garage and never got finished. I'm assuming but don't know 100% if these heaters are 240V, but that seems to be the most likely scenario.

So, for now, I've confirmed that the line is shut off at the breaker box. I've still got to unhook the standard 120V outlet from the line to ensure nobody accidentally turns it on/tries to use it later, but for now at least I think we're safe.

Thank you again for the replies, and I'll let this serve as a reminder of the dangers of making assumptions when working with electricity.

 

Having an electrician look at it would not be a bad idea. If someone left a cable like that exposed and connected to two different breakers both of which are big no-no's it makes me wonder what else was done improperly. I'd be checking the wire sizes going to the electric baseboard heaters and the wiring inside the panel for obvious problems.

 

I'm with you on that, Pilot. That was my first thought, too. What else has this guy done screwy? The person who owned the house not immediately before us, but two owners ago gutted and rebuilt the whole house, including building this garage, himself. He is a professional builder/contractor, but as we all know, that doesn't mean he did things correctly.

Still can't understand what possible reason there would be to connect the line to two different breakers. That seems to be unnecessarily complicated, and I'm not seeing any advantage.

 

I've seen it done in a panel where there was no room for a 2-pole (240v) Breaker. If your interested no need to remove the receptacle. You can can convert it to 120v just by changing the connection of one or two wires in the panel.