<p>Would an unopened metal junction box read “hot” on my circuit tester whether it was live with electricity or not?</p>
<p>I want to install a new receptacle on the wall to the right of my bathroom sink, tying into a junction box beneath the vanity counter on the left side of my sink (yes, it’s gfci protected). While there are three switches in proximity to the left receptacle and the junction box, one pair of them is hot and the single switch is not hot. The left receptacle is not hot and the receptacle downstream from the junction box (which I know is on the same gfci) is also not hot. Should I just open the junction box and check the wires inside with my circuit tester?</p>
<p>I’m not a licensed electrician, but am pretty familiar with residential wiring. Please proceed with caution.</p>
<p>I’m confused. In determining the metal box is “live” are you talking about touching one leg of the tester to the box to achieve ground (is the second leg of the tester on a known hot feed ? a known ground? a known common?) It would aid anyone diagnosing this if you were to explain your exact testing procedure (and equipment).</p>
<p>The metal box itself should not be hot (live). If it is, there is a wiring issue. Loose/missing wire nut, incorrect wiring. If the physical junction box is “live”, it is dangerous. You can test this by touching one leg of the tester to the metal box, the other leg to a known ground. Unless you are familiar with residential wiring, I would call a licensed electrician if you determine the metal box is indeed “live”. Are the feeds romex or armored cable?</p>
<p>The 3 switches in the gang box on the wall may well be fed by different circuits back to the service panel. Are the 3 switches single pole (controlling a circuit from only one location) or are any of the switches 3 or 4 way devices, controlling a circuit from more than one location?</p>
<p>I’m not sure I understand what you’re saying. You can certainly open the box and see what’s live but make sure you understand what might switch those wires because you don’t want to think they’re dead, flip a switch and find you were wrong. It would be odd in most houses to find unwired or dead receptacles, but I don’t know your house.</p>
<p>If you want to put in a receptacle, make sure it is also gfci. </p>
<p>I suppose if the question is what is the best way to figure out where to connect, then yes check inside the box and work from what you find.</p>
<p>Sorry…I did leave out some pretty pertinent info.</p>
<p>First off, I have flipped the breaker off on the target receptacle circuit, so the “dead” things are only dead because the breaker’s off.</p>
<p>I am using a voltage probe.</p>
<p>I broke down and asked my husband :D. He suggests that there are probably two circuits in the box, one of which is live; he further recommends that I flip breakers until both circuits are off and the box no longer tests hot. Smart guy my husband. :rolleyes:</p>
<p>If the circuit that feeds the new receptacle is already gfci protected at the breaker, the new receptacle does not have to be a gfci. If you are feeding from an existing gfci receptacle to a new one, this also applies, but you have to wire the new “downstream” receptacle in accordance with the “flow” instructions stamped or labeled on the existing gfci receptacle, or the protection is compromised. </p>
<p>Again, if at all in doubt,please consult with a licensed electrician.</p>
<p>Around here, we want gfci at the outlet as well. It’s not strictly necessary but it is a practice. One reason is that it’s easy to set and test an outlet.</p>
<p>Normally you wouldn’t find two separate breaker circuits feeding into the same junction box. If that were done, you would possibly find a 220 volt potential across two of the hot wires.</p>
<p>Normal circuits have two wires…a hot, and a neutral. Only the “hot” wire, which is normally black, is technically hot. It makes a circuit when connected through an applicance and switch to the neutral wire. The neutral wire is grounded at the pole transformer, and at the “service entrance” to the house. The ground wire is there, but is not part of the circuit. </p>
<p>Three way switches can make it more complicated to determine if you have the power off at the breaker. </p>
<p>If you are going to be involved in doing your own wiring work, buy a volt-ohm meter, and get familiar with the way the circuits work. Receptacles, (like all circuits) for instance, have the hot side, the neutral side, and the ground plug (when they are three pronged receptacles). They will measure 110 between hot and neutral, and also between hot and ground. neutral and ground will measure zero…all assuming that they are wired correctly. The smaller blade receptacle is the hot side. </p>
<p>If you are not certain that you have the power disabled, make certain you test everything you will touch with the VOM, and measure it to everything else. Mistakes in this area are quite unpleasant, and can be fatal. </p>
<p>I would think the right electrician could do what you want pretty easily and for a nominal cost.</p>