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Adding a switch to current circuit

460 Views 13 Replies 6 Participants Last post by  cvh4878
I have a simple 20 amp, 4 receptacle circuit, wired with 12-2 Romex, with a standard duplex receptacle at the end of the run. I want to tap into this receptacle to extend the circuit so I can add a new single pole switch. Ultimately the switch will control a couple of ceiling lights in the attic.

To extend the circuit, I plan to connect 12-2 cable to the unused screws on the end of run receptacle, run to the new switch (tying neutrals together inside the new switch box), then run new cable from the switch to the new light fixture in the attic.

I don't foresee any problems doing this, unless I am missing something in the equation. Basically, I am just utilizing power from the end of run receptacle to get power to a new switch, then from there off to a new light fixture.

OK to do so?
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That will work. It's your choice but I never use a receptacle or any other device to make a junction. Better to use pigtail leads for wire nutted connections to serve the receptacle so it won't become part of a down stream circuit.
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Thanks. So what you are saying is to splice into the hot side of the receptacle instead, rather than utilizing the two available unused screws on the receptacle?
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Yes, that's considered better workmanship by most professionals and inspectors like it too.

Same goes for not using the back stab holes you'll see on some receptacles. The screws are not as bad for becoming loose connections as the back stabs but why chance it. It also makes replacing the receptacle a lot easier job, if you ever need to.

Don't cut the wires... remove them and connect a 6" pigtail along with your new wire.
Better to use pigtail leads for wire nutted connections to serve the receptacle so it won't become part of a down stream circuit.
Good advice. Unfortunately the other 3 receptacles before the last are probably daisy chained instead of pigtailed.
Guess you have to start somewhere.:wink2:
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Greatly appreciate everyone's experienced advice. I will go ahead and splice the connections and do it right. I now understand the reasoning, but didn't think it through that far in the "planning it out" phase. �� Tks!!!
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Greatly appreciate everyone's experienced advice. I will go ahead and splice the connections and do it right. I now understand the reasoning, but didn't think it through that far in the "planning it out" phase. �� Tks!!!
Well if you feel ambitious you could re-wire all of the outlets with pig tails.
Then if one of them should fail, and that does happen, the rest would still work.
Using the screws would be my choice. There is no advantage using nuts instead of the screws.
I will file away your suggestion, but taking action any time soon is likely doubtful! Should I win the lottery and break free of my work life, then I may set aside a day and do it. ����
Using the screws would be my choice. There is no advantage using nuts instead of the screws.
Relying on the device to provide continuity is taking a chance.
There are some very cheap receptacles available that are less than adequate for powering an entire circuit. Pigtails ensure that a solid wire connection is available at each device. In addition to that, it is actually easier to install an outlet with only two wires on it than to try to bend 4 wires into place when using the screws.
The code supports either way.
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I consider screw connections more reliable than wire nuts. Plus in Canada wire nuts count for box fill.
The bulk of my electrical experience was in commercial and industrial applications. It is standard practice to not use a device for a junction. It is especially important to not do that on a multi phase circuit using a shared neutral. I don't do that kind of work or recommend it to others.

We built several chain restaurants to turn key status and if we used less than specification grade devices and didn't pig tail them, their maintenance man would catch it and we'd get some flack come bid time for the next job.

Some equipment suppliers even specify pig tailed receptacles... for instance the POS system receptacles. Replacing a receptacle that killed the cash registers downstream wouldn't be acceptable. Some POS systems lose program data and require a reload from backup when power is lost during a memory write transaction.

You can appreciate how popular you would be if you had to replace some device and removing it shut down several other important operations downstream. A shared neutral could kill several downstream devices.

It also puts the electrician in harms way to a greater degree since he will usually be encouraged to do the repair live to avoid a shutdown. A pig tailed device can be much easier to work with live.

I notice residential electrical standards and inspectors allow lots of things that aren't commonly done at the commercial level. I have no quarrel with that but doing things like running NM cable or UF cable in conduit and using devices for junctions are among some of the things that you won't likely see outside of residential work. We never used any 49¢ receptacles like I see in many homes either. The spec. grade stuff costs more and it costs more time to pig tail receptacles. It up to the electrician to decide whether it is up to his standards.

If you can't make the wire nut connection in a professional way, maybe you're better off using the screws. I had some people like that working for me at times. Code allows both ways... to each his own. As the saying goes, YMMV.
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Since we don't know the cubic inch capacity of the last receptacle box that you plan on tapping into one suggestion would be to be sure that adding the romex will not cause an over fill of the box. Just because you may be able to jam all the conductors and receptacle back into the box does not mean it is safe and to code.


Any idea what type of box or the cubic inch capacity of it is?
You can use pigtails or use the receptacle screws for extending your switch. As far as residential is concerned it’s really up to you...an added light fixture is so low on power consumption I wouldn’t think twice about just using the screws.
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