I was checking outlets to insure that they were wired correctly, and in doing I discover this one. The outlet tester said it wasn't grounded. There is one black wire coming from what appears to be a light switch, wrapping around a brass screw and going off to another light switch(I think). The other black wire goes elsewhere. Is this appropriate?

THank you, Kathleenoutlet image

3 Answers 3


If the outlet tester said the outlet is not grounded, it is not wired properly.

The three black wires are not the problem. this is a common technique for bringing power to an outlet and then continuing the power down the line to other outlets or fixtures.

The connection between the outlet and the switch may be one of two things: - if the switch is downstream (further away from the power source) the outlet is passing current to the switch and then on to a fixture. - if the switch is upstream (between the outlet and the power source), the outlet, and everything else powered by the black wires shown, are controlled by that switch. It is not possible to tell from the wiring shown.

The white wires in the background may be correct, but it is hard to be sure from this picture.

The real problem is the lack of ground. There should be a green or bare wire in the outlet box. This wire needs to be attached to the grounding screw of the outlet. If it is already attached to something else in the box, you need to remove the grounding and attach two pigtails to that ground and then attach tem to the other grounded item and the outlet.

Given the information in your question, it sounds as if you have little experience in handling electricity. It might be advisable to have this project done by someone with a bit more experience while you look on and become more familiar with power.

Above all, make sure that the power to all wires in the box is off (test with a non-contact tester) before attempting anything.


If you tested the ground while the outlet was out of the electrical box, that might explain why you aren't getting a ground. It looks like you have a metal box, which should be grounded. It's important that all metal boxes are grounded. There are receptacles which are "self grounding", which will test as grounded only when installed in the box. If your receptacle has a bit of copper wire in contact with one of the mounting screws, then it is self grounding.

There are a few things that stand out to me in the picture:

  1. It looks, to me, like there are two wires connected to a screw. If so, this is not right. Only one wire per screw. If this restriction is a hinderance, you will need to make a pigtail with a wire nut.

  2. There is way too much copper showing. The wire should be striped just enough to wrap the wire around the screw terminal. The insulation should stop just short of the screw, and not be under the screw.

  3. It looks like the wall was drywalled over the original install. You should have an outlet extender to make the box flush with the wall. If the receptacle was installed so that it was 1/2 inch away from the box, this could explain why the box isn't "self-grounding". If the box extender is not metal, then you will definitely need to add a grounding wire to the receptacle as described in other answers.

If the receptacle is connected to a switch, you may want to check out the answer I gave yesterday concerning a problem that can occur if the receptacle is not configured properly in this scenario. How to identify the purpose of this switch?


With the exception of a lack of ground, it appears perfectly normal to me. Circuits are wired often as a sequence of outlets that are wired in parallel, so the hot from one outlet will go to another. And when running the wire, some installers will simply cut away the insulation without cutting the wire itself. The pro to this is that it's much less likely to have a broken or shorting connection since the copper is continuous. The con is that you have to be very careful when measuring your wire where most installers leave about a foot of wire in the outlet during rough install and cut away the excess when installing the receptacle. On a side note, I personally hate the push in connectors on the back, but it's perfectly reasonable to use those too.

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