I recently did some rewiring work at my house to install an electrical outlet in a room where I have an electric baseboard heater. The heater is on a 20-amp circuit with 12 ga wire which runs down inside the wall from the attic above. I wanted to add an outlet in the room, which I’m renovating, and the heater circuit was the closest live line I could get to.
I tapped into the line in the attic, added a junction box, and ran a new 12 ga line out of the box and down inside the wall. Back in the room I cut a hole in the wallboard, inserted a plastic box, and connected a duplex outlet to it. I only intend to use the outlet for a plugging strip for phone chargers and what-not, nothing that would draw excessive load. Everything on the 20-amp circuit would only come to about 13 amps, so I have plenty of headroom.
I realize I should have used a 20-amp outlet but I only have 15’s on hand, so that’s what I used until I can pick up a 20. At the end of the day I plugged my ShopVac into it to clean up the room a bit and the thing sounded like a jet engine, and I quickly shut it off. There was a lingering ozone-y smell for about an hour. I checked the outlet with a meter and was getting about 220.
If I switch to a 20-amp outlet will I still be getting 220? Am I going to be able to use this outlet for something like a cell phone charger which only pulls less than an amp, or do I have to rewire the outlet with 14 ga wire from a 15 amp circuit?
Without having a very clear picture of your wiring situation it sounds as if you’ve mistakenly tapped into a 220 circuit which was dedicated to a 220volt baseboard heater . You might be able to confirm that by looking closely at any writing on the heater.
Changing your outlet won’t change the voltage.
At the risk of hurting your feelings I think that you aren’t prepared to work with this stuff. I’d rather have you mad at me and alive, but you need to call in a professional and have him repair and replace the stuff you’ve done.
Please don’t touch anything before you call in for help.
Your problem isn’t the outlet, you’ve tapped into a higher voltage circuit designed for the high load of a heater. You’re going to get 220V no matter what kind of outlet you attach, no matter what gauge wire you use. There may be a way to get back down to 110V, by capping one of the hot wires and running a new neutral, but that’s way beyond my skill level and yours.
Sorry, but there’s no way that the outlet form function can change the voltage. I’m guessing your heater is on a 220 Volt circuit (although that seems a bit unlikely if it only has 12 gauge wire).
The questions you’re asking indicate that you’re currently out of your depth here and should call in an electrician.
But, to quickly summarize, the gauge of the wire has nothing to do with the voltage. The gauge of the wire determines the maximum amperage that the circuit can handle. So using 12 gauge wire instead of 14 is almost always OK (except that 12 gauge is stiffer and may not be suitable for some connectors or smaller junction boxes). Using 14 gauge when you should use 12 is NOT OK, because you’re using wire that doesn’t have enough capacity to handle the current load.
Likewise, a 20A junction box is pretty much identical to a 15A junction box except that it accepts plugs that have a differently shaped pin so that you can’t accidentally plug a 20A appliance into a circuit that’s only wired for 15A.
All of this is predicated on the belief that you’re in the US and have normal 120V household service.
P.S. Your Shop Vac is probably dead – I’d be very reluctant to keep using it after subjecting it to 220 Volts. You probably heated all the insulation off the windings.
i agree that it seems the circuit was likely 220V as evidenced by measuring 220V (assuming the measurement was done correctly). if the circuit breaker you turned off to work on this was a dual breaker that is also evidence that it is a 220V circuit.
you show some knowledge of electricity. though you also show a lack of some very important issues.
your lack of knowledge is a hazard to life and property. just not killing yourself, either though knowledge or luck, doesn’t mean you haven’t created a hazard to life or property that won’t show up later.
good you didn’t die or your house set on fire. if your shopvac isn’t dead you likely have shortened its life.
there are little details to doing wiring properly to be safe and lasting. knowing some principles of electricity or some data values doesn’t mean you will do the wiring correctly. get some experienced and qualified help.
I definitely did something screwy here, I admit it, but I’ve done a lot of electrical work before. Most of the stuff I do I get a permit for and an inspection after, and I’ve always passed. In fact, I did the wiring for the baseboard heater myself and passed the inspection.
I think I will call an electrician because I’m really curious what’s going on. In the meantime, the breaker’s off.
Ha! When I was a kid my dad remodeled the bathroom and ended up with a 220v outlet. We found out when I plugged a hair dryer into it and I swear to god it looked like a jet afterburner. Fortunately I didn’t have it pointed at my head at the time.
Ah…good times. But it was a good lesson. I check the devil out of every wire I’m working on and check the voltage and polarity of my work every time.
My father also did a lot of electrical work himself, but I remember when he managed to bridge two 110 circuits into a 220. Sometimes the wires have a mind of their own.
One of the keys to doing your own electrical work AND living to a ripe old age is to never think, “there’s no way I could have screwed that up.”
You shouldn’t tap into a heater circuit to start with. Electric heaters draw a lot of current, and adding an outlet is just going to eventually overload the circuit. Maybe you personally will only plug a phone charger into it, but someone many years from now could easily want to use that outlet for something that draws a lot more current.
If you did the heater wiring then you should have known it was 220. The heater circuit should have had red and black wires to let you know that it was 220 instead of 110. If the wires are black and white then you’ve got another problem as well, and it is possible that the inspector didn’t catch it.
That ozone smell was from the motor coils in your shop vac being fried. If it still runs then you’ve probably shortened its life by quite a bit.
I have quoted this because it is very important and is worth repeating. You seem to think that you have more competence than you do, just because you’ve done this sort of thing many times before and it has always passed inspection. If you are going to keep doing your own wiring, I would very strongly suggest that you read up a bit more about electricity in general. Don’t take this as an insult, and I am all for people learning to do things on their own. I (and probably many others on this board) will be more than happy to answer any questions you might have.
As for your situation, you need to find another wiring run to tap into. The heater circuit may be close and convenient, but it’s not suitable for what you want to do. You seem to be willing to let an electrician sort it out from here, which is a good plan IMHO.
If you don’t already have an AFCI on whatever circuit you end up tying this into, I would recommend adding one, especially since you plan on using this outlet with a power strip. Faults in extension cords and power strips are exactly what AFCIs are designed to protect you from.
You’re probably right that I need to educate myself on some details, but I now know what I did wrong- it was indeed a 220v circuit. I knew that when I put it in but forgot it when I tapped into it partly because I didn’t turn off the breaker myself- I asked my wife to do it while I was upstairs mapping out what I wanted to do. I tested it to confirm it was off before working on it. If I had turned it off, I would have seen and remembered that it was a dual-pole breaker and a 220v circuit.
I used 12/2 wire, with the white as another hot (and so marked with red tape at the panel), but when tapping into it in the attic it just looked like any other 12/2 line. I’m just going to disconnect what I’ve done and tap off a 120v line and leave the heater circuit alone.
Well, it should have been marked with red tape at that end, too. To tell any other electrician (or remind you) that it was live 220V. Mark it now, when you disconnect your tap.
And switching that tap to another 120V circuit is the right thing to do.
Big mistake. Always personally confirm the type of incoming power and that the power is off before starting any work. For that matter, my factory’s lockout-tagout procedures require that a tech lock out the incoming power with his or her personal lock before beginning work unless they are close enough to the disconnect to keep it in their personal control while working. In theory, we could be fired for handing someone else our lock to place on a disconnect.
And people wondered why I didn’t want any help when working on something…
The OP’s heater circuit now has three places where voltage should be indicated by conductor color: inside the panel, inside the attic junction box, and inside the heater itself (there are 120V baseboards, and somebody might try to replace one with the other at some point). Also, I’d identify the box in the attic: write on the cover the circuit number from the panel, the voltage, the room the heater is in and “heat,” or something like that.
You are extremely fortunate you did not burn down your house and/or electrocute someone. I don’t mean to pile on but … why didn’t you test the voltage at the junction box before tapping in to it? Especially when you had someone else turn off the breaker for you. (A big no-no!)
I would also strongly advise against any “tapping” into existing circuits. I know it’s more work but I almost always fish back to the panel and create a new circuit.
testing a circuit to be dead is important. put your tester on a known good circuit (easy and safe to use a receptacle) and get a positive response before you trust the tester to indicate a dead circuit with a negative response.
testing a circuit to be live before working on it can be a hazardous step because of having loose exposed live wiring, which may stay loose and exposed until the breaker is turned off. sometimes this has to be done though you want to do it only when needed.
I just gotta tell you Corkboard that it concerns me that you still seem to be willing to work on this.
You made a number of safety omissions, demonstrated some outright carelessness and shown some poor methodology in working with this stuff.
Bring in some help! If you aren’t willing to pay for a pro to do this at least bring in somebody who has worked with house voltage before. Hopefully between the two of you the job will be completed safely and competently.
Thanks again for your comments. Contrary to the general consensus, I’m not a complete idiot. I admitted I screwed up. I know what I did wrong. I learned from my mistake and from the advice here; some of it, anyway.
I’ve done a lot of electrical work in both of my homes, all code-compliant. While I’m grateful for the concern, I’ll take it from here, thanks.
Now, I need to go find a fork to get my bagel out of the toaster.