Will this circuit work?

Idoc4u · Feb 21, 2010

I am will be adding a 20A breaker to my breaker box and intend to run 12-2 WG wire through EMT conduit to an unfinished basement bathroom.

Could you guys take a look at my wiring diagram and let me know if you feel this will work. The green pencil lines for the ground may be hard to see.

I will have 20A service but a 15A receptable, not 20A as depicted in the picture.

Can I use the 3 switch box like a junction box with all of those pig tails, or should I incorporate a junction box?

Thank you for your advice.

Dlarrivee · Feb 21, 2010

The 3 gang box will be where all of your connections are made. Why would you need a separate junction box?

Sponsor · 2022-01-29T12:20:58-0800

Jadnashua · Feb 21, 2010

Boxes are available in various depths. There is a volume associated with it. If you do not exceed the fill volume for the box, you can put as many leads in there as you want. Now, how to calculate that volume gets a little harder. One way to give yourself a little more room, if required, is to use a 4-gang box, when only using three switches. Make sure the receptacle is a gfci.

Idoc4u · Feb 21, 2010

circuit question

I don't recall the 3 gang switch box dimensions, but would guess about 6x4x2.125. I realize that there are only a certain number of wires allowed per box according to code. I believe a 4x2.125 box allows a max of 13 #12 wires, but I'm not certain.
I don't want to jam more wires than I should into the box.

How would I use a 4 gange box with 3 switches? Would I have to have a blank cover over one of the switch locations?

Thanks again for the replies.

Andrew21 · Feb 21, 2010

WOw excellent question! I was thinking of the similar situation. This is great!

Question, how many breakers are you using for this? (if this is the correct terminology). I was thinking of using 3 breakers in the panel for this. I will have a fan/light (not sure about the light), vanity light, outlet/GFCI, and possibly 2 recessed cans but with low wattage bulbs. Thinking about putting the vanity and cans on one circuit but don't know if this is too much.

thanks!

Jadnashua · Feb 21, 2010

Most companies make cover plates with a blank at one end in various sizes especially for this. You only need one breaker for the bathroom unless you have something like a whirlpool or some other high current device. Unless you are planning multiple big loads (say a hair dryer and hot rollers) at the same time, one 20A circuit with some lights should be okay. Now, if you have lots of wattage in lights, you may want to separate them. It's sort of nice to not have the lights go out if you overload the circuit.

Iminaquagmire · Feb 21, 2010

Your layout and where the wire comes into the room would determine the best way to run the wires. Code states bathroom receptacles require a 20amp GFCI circuit. You can feed the lights with this same circuit, but if you do this, the circuit cannot feed anything out of the bathroom. I'm confused as well on how to use a 4 gang box with only three switches.

If you feed from the circuit breaker into the switch box, you have one hot wire and neutral coming in. Pigtail the hot and neutral from the feed from the breaker, to the feed from the 1st (would be GFCI) receptacle and run it out of the box. You can use the switch box to get power from the breaker to the switches and as a junction box to get power to the receptacles. Off your hot pigtail, take your power off for your switches. From there you can go to your lights and fan. Or you can put the receptacle in the four gang box itself and do the same. Or you can run separate circuits for the receptacles and the lights.

hj · Feb 22, 2010

I would NOT use pigtails, but would take a single length of wire and strip sections of it to wrap around each switch terminal creating a "three switch module" which would take up a lot less room inside the box.

Jadnashua · Feb 22, 2010

Leviton makes a 2-gang cover with one blank side. They also sell blank inserts for their Decora sized switches and controls. You could use a larger box than you have devices, and put a blank cover in the unused slot, if you needed more space. there are probably ways to avoid that, but it is an option, if required.

Bpetey · Feb 22, 2010

They make 3 switches in a single gang unit. There is also a modulare cover system that you can use for a 3 or 4 gange box.

Idoc4u · Feb 22, 2010

If I have a 20A breaker with 12-2 WG serving the bathroom, would there be any problem with using a 20A GFCI outlet vs a 15A GFCI outlet? I can't see any reason why this would not function properly. It may not be common practice to locate a 20A GFCI outlet in that location, but I would think it would work properly since it is being served by a 20A breaker and #12 wire.

Thank you.

Iminaquagmire · Feb 22, 2010

There is no reason not to, you just don't need to. If you already bought one, its fine to use. The only thing different really is that the prong openings can accommodate a 20 amp plug. But I've never seen any device you would use in a bathroom that uses that kind of prong orientation.

Alectrician · Feb 22, 2010

Your circuit is correct. You understand the basics.

You can eliminate one cable from the 3 gang box by hitting the recep box first.

Use plastic nail on boxes

Run all cables into the top of the 3G box , run the switch legs into the appropriate space directly above the switch location
and your makeup will be "cleaner".

Don't leave too much sheath on the cable!!

Make up the grounds/pigtails first and tuck them back. Consider using only one ground pigtail and looping it thru all 3 switches because 7 or 8 #12's will be tough to squeeze under a wirenut.

Make up the neutrals second and tuck them back. Make up the hots/pigtails and get them tucked back to leave room for your switches.

.

Dlarrivee · Feb 22, 2010

Andrew21 said:
Question, how many breakers are you using for this? (if this is the correct terminology). I was thinking of using 3 breakers in the panel for this.
thanks!

It's a good thing you're not wiring an entire house then, you'd need a pretty large panel to run every single device or plug on its own breaker.

You might want to do a bit more reading on this.

Andrew21 · Feb 22, 2010

dlarrivee said:
It's a good thing you're not wiring an entire house then, you'd need a pretty large panel to run every single device or plug on its own breaker.

You might want to do a bit more reading on this.

haha I know. Thats why my dad is going to do the wiring. He's good at it and understands it more that I do. I want to learn but afraid of learning the wrong things. I'm looking into a school or college program that offers electrical classes for a fee. I'll pay to understand this and doing it right. When I do, i'll send the link to make sure its a good class =)

Furd · Feb 27, 2010

idoc4u said:
I am will be adding a 20A breaker to my breaker box and intend to run 12-2 WG wire through EMT conduit to an unfinished basement bathroom.

Running cable through conduit is difficult, if you need conduit for physical protection I strongly suggest that you use individual conductors.

Will this circuit work?

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