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Old 07-09-2014, 11:07 PM   #1
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Single Gang Double-switch to Double Gang w/ Two Single Switches


All - (Pls see pix below)

I'm no electrician and am converting a single-gang double switch (which controls a ceiling fan and a light attached to the bottom of that same ceiling fan) to a double gang box that will have 2 separate switches to control that same ceiling fan and light. My son and I think the following info is correct:

- The light blue wire carries power from the attic to the switch. Pls note that in the picture the blue wire is NOT cut (sorry for the blurry pix) but is merely stripped, makes contact with the switch and then continues down through the conduit to energize an outlet slightly right and below this switch (not pictured).

- The 2 black wires carry power from the double switch back up through the wall to the ceiling fan and light; 1 black wire is for the ceiling fan and 1 black wire is for the ceiling fan light.

- The white wire is simply a common/return line bringing power back from the lower outlet (bypassing the switch) up to the junction box in the attic.

- There is no ground wire.

Have I got all that correct?

If so....

Question #1 - I know I need to cut the light blue wire and connect it to the new light switch (with the dimmer), but to what specific terminal? Top left? Bottom left?

Question #2 - I need a jumper wire to carry power from the new dimmer light switch on the left to the new fan switch on the right?

Question #3 - If so, what terminals do I connect from/to with the jumper wire?

Question #4 - With the limited number of terminals (4 total) in the pix, should I connect the blue wire bringing power down to the left switch with the jumper wire taking power from the left switch to the right switch? In other words, physically connect BOTH the downward traveling blue wire and the jumper wire to the SAME terminal screw?

Question #5 - Connect the (newly cut) lower blue wire to one of the terminals on the (right) fan switch to get power down to the lower outlet? If so, what terminal?...top or bottom?

I'm pretty sure I know what to connect where but burning down my house due to wrong wiring would not be fun so thanks in advance!

Single Gang Double-switch to Double Gang w/ Two Single Switches-single-gang-double-switch-wiring-1.jpg

Single Gang Double-switch to Double Gang w/ Two Single Switches-single-gang-double-switch-wiring-2.jpg

Single Gang Double-switch to Double Gang w/ Two Single Switches-l-light-switch-dimmer-r-fan-switch.jpg
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Old 07-10-2014, 04:45 AM   #2
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Cut the blue wire and pigtail the ends together with a wire nut and 2 short jumpers. Connect a jumper to each switch (either terminal, it does not matter). Connect the black wires to the other terminal on each switch.

You have a ground, it is the conduit. Buy sell grounding switches or run a jumper to a ground screw in the back of the box.



Not sure why you are doing this, but the hardest part of the job will be changing the box.
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Old 07-10-2014, 05:35 AM   #3
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Changing the box or adding another gang is going to involve drywall work.

If you are just using single pole switches it. Does not matter top or bottom screw. Any special sw8tch should have a wiring diagram.
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Old 07-10-2014, 06:44 AM   #4
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Typo in my post

Self grounding not sell grounding.
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Old 07-10-2014, 08:42 AM   #5
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When you've got more than once device in a box (or connections that continue through the box) it's typical to use a short pigtail for each device. So your blue wire from the top would be twisted together with the blue wire leading down and two new short pigtails for the switches. Those would lead to the black terminal on the new switches. Then the switched output from the switches would lead up to the respective devices on the upward leading black wires.

Note, some newer switches and dimmers might require a neutral connection of their own. You'd use a new pigtail for each of them, as necessary. Smart switches or ones with an indicator light typically require their own neutral. From the looks of your box you don't have a lot of length to play with regard that neutral. Whoever did the wiring did you no favors setting it up that way.

How are you planning on adding the 2nd gang? Because it's very likely you'll come up short on that white neutral wire...
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Old 07-11-2014, 01:57 AM   #6
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Quote:
Originally Posted by rjniles View Post
Cut the blue wire and pigtail the ends together with a wire nut and 2 short jumpers. Connect a jumper to each switch (either terminal, it does not matter). Connect the black wires to the other terminal on each switch.

You have a ground, it is the conduit. Buy sell grounding switches or run a jumper to a ground screw in the back of the box.




Not sure why you are doing this, but the hardest part of the job will be changing the box.
Yes, getting the metal single-gang box out was a pain in the rear. It was spiked/cleated to the stud next to it. Don't know why I didn't realize that ahead of time.

1 - The power-carrying wires are solid copper 12-guage. Don't the jumper wires need to be 12-gauge, too?

2 - Pls correct me if I'm wrong, but the wire in your pix is not the jumper wire, is it? Isn't that the ground wire you recommend?
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Old 07-11-2014, 02:04 AM   #7
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Quote:
Originally Posted by wkearney99 View Post
......So your blue wire from the top would be twisted together with the blue wire leading down and two new short pigtails for the switches. .....Those would lead to the black terminal on the new switches. Then the switched output from the switches would lead up to the respective devices on the upward leading black wires.

Note, some newer switches and dimmers might require a neutral connection of their own. You'd use a new pigtail for each of them, as necessary. Smart switches or ones with an indicator light typically require their own neutral. From the looks of your box you don't have a lot of length to play with regard that neutral. Whoever did the wiring did you no favors setting it up that way.

How are you planning on adding the 2nd gang? Because it's very likely you'll come up short on that white neutral wire...
- So FOUR wires pig-tailed together under the wire nut, right?

- "Smart switches or ones with an indicator light typically require their own neutral".....there's no indicator light on either of the 2 new switches. So how do I know if any of my 2 new switches needs its own neutral?

(FYI, 2nd gang box will be added immediately to the right of where the one is pictured now. Already cut the drywall for it today. Reason for going from 1 double-switch to two single gangs is I want to make this switch match the light-switch style (Cooper Aspire) throughout the rest of the house.)
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Old 07-11-2014, 05:04 AM   #8
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Quote:
Originally Posted by Twister View Post
Yes, getting the metal single-gang box out was a pain in the rear. It was spiked/cleated to the stud next to it. Don't know why I didn't realize that ahead of time.

1 - The power-carrying wires are solid copper 12-guage. Don't the jumper wires need to be 12-gauge, too?

2 - Pls correct me if I'm wrong, but the wire in your pix is not the jumper wire, is it? Isn't that the ground wire you recommend?
Yes the jumpers(pigtails) need to be #12.

The green wire in my pix is to connect the ground from a screw in the back of the box to the switches..
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Old 07-13-2014, 01:51 AM   #9
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Size of jumper wire depends on which electrical code the premises is subject to, if any.

The CEC and ESC for example require same size be used, in your case apparently 12 AWG.

The NEC has an exception allowing us to go one size smaller, here 14 AWG, if the [smaller] wire does not leave the same enclosure, as appears to be your case.

And some jurisdictions like Vermont for example, still exempt owner-occupied single-family homes from any and all code requirements, meaning you could use 30 AWG or smaller if you were so inclined, though I wouldn't recommend going smaller than one size down (14 AWG).

FWIW, all electrical inspectors working under the ESC have consistently accepted the one size smaller I typically use under the NEC exception, recognizing that safety isn't compromised to any extent thereby.

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Old 07-13-2014, 06:50 AM   #10
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And note that when you put the wires together you need to twist them tight BEFORE putting the wire nut on them. Use a pair of lineman's pliers to make a tight twist and clip the end. The wire nut is not there to make the twist, that has to be done first with the pliers.

Your switches should include wiring diagrams. That would tell you if they need a neutral connection.
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Old 07-13-2014, 07:54 AM   #11
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Pretwisting is a matter of preference not code. Personally I twist with solid wire and do not wth stranded. Not sure why I do it that way but is what I was taught.
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Old 07-13-2014, 09:13 AM   #12
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Pretwisting or not is primarily a matter of what type wire connector you're using. Secondarily, what type and wire size(s) you're connecting. If you always do it or don't, you'll be in trouble quickly.

E.g, original Marrette type (2 pc unit with brass screw in inner piece; still sold at most if not all supply houses, fortunately) should NEVER have any wires twisted into them. Ditto with all split-bolt type wire connectors, inter alia.

If you don't know why you're doing something a certain way, don't do it, until you find out. In the case of splicing wires, don't use any wire connectors. Instead, solder the connections and insulate using a couple of layers of PVC electrical tape; rubber tape if the place is subject to moisture. (UL and CSA approved electrical tapes have one layer good for 600V worth of insulation. Second layer is therefor for security, not insulation value. Add'l layers are waste of tape, and space.) Overlay with a couple of layers of friction tape if there's likelihood of underlaying tape rubbing against something.

Remember too that every pair of wire connectors counts as one wire for box fill. Eliminating wire connectors thus allows you to legally stuff more wires into a given size of box. (This is the same under all electrical codes.) And yes, pretwisting is nec'y for most solder connxns.

When you've learned how to properly use different types of wire connectors, gradually resume using them; limited to only those you've learned.

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Old 07-13-2014, 10:17 AM   #13
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Quote:
Originally Posted by VRP View Post
Pretwisting or not is primarily a matter of what type wire connector you're using. Secondarily, what type and wire size(s) you're connecting. If you always do it or don't, you'll be in trouble quickly.

E.g, original Marrette type (2 pc unit with brass screw in inner piece; still sold at most if not all supply houses, fortunately) should NEVER have any wires twisted into them. Ditto with all split-bolt type wire connectors, inter alia.

If you don't know why you're doing something a certain way, don't do it, until you find out. In the case of splicing wires, don't use any wire connectors. Instead, solder the connections and insulate using a couple of layers of PVC electrical tape; rubber tape if the place is subject to moisture. (UL and CSA approved electrical tapes have one layer good for 600V worth of insulation. Second layer is therefor for security, not insulation value. Add'l layers are waste of tape, and space.) Overlay with a couple of layers of friction tape if there's likelihood of underlaying tape rubbing against something.

Remember too that every pair of wire connectors counts as one wire for box fill. Eliminating wire connectors thus allows you to legally stuff more wires into a given size of box. (This is the same under all electrical codes.) And yes, pretwisting is nec'y for most solder connxns.

When you've learned how to properly use different types of wire connectors, gradually resume using them; limited to only those you've learned.

Vic
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Soldering is way too cumbersome of a procedure and is way outdated. Mechanical connectors like wire nut and push-in connectors are a safe and proven method.

Also the rule about wire nuts counting towards box fill does not apply under the NEC.

I have never seen the two piece wire nuts in a supply house, only pictures on the web.

There is no need to pre-twist in a split bolt since you are only splicing two conductors, one on each side of the clamp bar.
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Old 07-13-2014, 01:32 PM   #14
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My comments in red
Quote:
Originally Posted by VRP View Post
Pretwisting or not is primarily a matter of what type wire connector you're using. Secondarily, what type and wire size(s) you're connecting. If you always do it or don't, you'll be in trouble quickly.

We were discussing wire nuts.


E.g, original Marrette type (2 pc unit with brass screw in inner piece; still sold at most if not all supply houses, fortunately) should NEVER have any wires twisted into them. Ditto with all split-bolt type wire connectors, inter alia.

Not used very often today

If you don't know why you're doing something a certain way, don't do it, until you find out. In the case of splicing wires, don't use any wire connectors. Instead, solder the connections and insulate using a couple of layers of PVC electrical tape; rubber tape if the place is subject to moisture. (UL and CSA approved electrical tapes have one layer good for 600V worth of insulation. Second layer is therefor for security, not insulation value. Add'l layers are waste of tape, and space.) Overlay with a couple of layers of friction tape if there's likelihood of underlaying tape rubbing against something.


HUH?

Remember too that every pair of wire connectors counts as one wire for box fill. Eliminating wire connectors thus allows you to legally stuff more wires into a given size of box. (This is the same under all electrical codes.) And yes, pretwisting is nec'y for most solder connxns.

Where in hell do you get this?

When you've learned how to properly use different types of wire connectors, gradually resume using them; limited to only those you've learned.

Are you on drugs?

Vic
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Old 07-13-2014, 02:20 PM   #15
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My apologies Jim... I could have sworn the NEC included wire connectors for box fill. But now having chkd my 2011 & 2008 editions, you appear to be correct. It appears to be another NEC deficiency. (We certainly have the proovision in the CEC & ESC!)

Many split-bolt connectors, however, are listed for substantially more than two wires. All depends on the wire sizes.

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