Switch loop back to house

[mike93lx]

I want to run wire back to my house to control 2 lighting circuits on a detached shed. The shed will be fed with 20a MWBC, so no panel in the shed. Just lighting and a couple receptacles with a DP 20a toggle switch for the disconnect.

To keep the 20a breaker rating kosher, I'll run #12. Wire will be THWN, underground in pvc conduit. Likely 1/2"

The switches will both be three way, and likely just simple switches that don't need a neutral, although I would like to have one in case I do something different down the road.

I can pull a single neutral and ground to cover both switches, correct? Other than that, I know I'll need two hots for each, so 6 wires total, which would put me at 28% fill in 1/2

 

[wyliesdiesels]

yes since its a MWBC you can use 1 neutral. 1 ground can be used for multiple circuits as well so no issue there.

 

[mike93lx]

yes since its a MWBC you can use 1 neutral. 1 ground can be used for multiple circuits as well so no issue there.

Thanks Wylie

 

[mike93lx]

For the hots, can I use colors other than black and red? I can always identify them, but using other colors would make it foolproof. Something like blue and gray, maybe

 

[wyliesdiesels]

you can use anything but white or gray (neutral identifier) or green (EGC identifier)

 

[nadogail]

Avoid Gray for identifying a hot (current carrying) conductor, Natural Gray is an alternative color for Neutrals.

 

[mike93lx]

Got it. No Grey. Thanks guys

 

[Terry D]

Since it is in pipe, A neutral is not required now since it can be pulled in later. But it would keep you from having to go back later to install one if ever needed

 

[mike93lx]

Since it is in pipe, A neutral is not required now since it can be pulled in later. But it would keep you from having to go back later to install one if ever needed

Yeah, I know, but honestly, it's just not worth trying to worry about later. If I never need the neutral, it's about $20 wasted. I can live with that

 

[mike93lx]

I just realized I am missing a wire. Can someone confirm?

1 egc
1 neutral
1 line (to supply both switches with constant power)
2 travelers for switch 1
2 travelers for switch 2

So to do a pair of remote 3-way switches, I need 7 wires including a neutral, not 6.

The run is reasonably straight, but I will have at least two 90's and a 45, if I can't curve the conduit. I'm planning to use stranded, but at 7 #12's, 1/2" pvc is starting to feel small, no? Feels like 3/4 would probably be worth it, dropping the fill from 33% to 18%. Thoughts and opinions?

 

[Terry D]

If you are installing the neutral now, yes, you will need 7 #12's total. You are allowed up to 8 #12's in 1/2 inch PVC, but that doesn't mean it will be easy getting them in there. I would defiantly go with 3/4 PVC.

 

[mike93lx]

If you are installing the neutral now, yes, you will need 7 #12's total. You are allowed up to 8 #12's in 1/2 inch PVC, but that doesn't mean it will be easy getting them in there. I would defiantly go with 3/4 PVC.

Thanks Terry

 

[mike93lx]

If you are installing the neutral now, yes, you will need 7 #12's total. You are allowed up to 8 #12's in 1/2 inch PVC, but that doesn't mean it will be easy getting them in there. I would defiantly go with 3/4 PVC.

Curious how a pro would do this. Would you just run one - two colors and identify the wires with colored tape/labels, or would you run various colors?

At a roughly 60' run, I'm not at a great length to use a bunch of colors without having tons of leftover.

 

[Terry D]

Curious how a pro would do this. Would you just run one - two colors and identify the wires with colored tape/labels, or would you run various colors?

At a roughly 60' run, I'm not at a great length to use a bunch of colors without having tons of leftover.

I know what you mean. I would run black for the common and 2 reds for one set of travelers and 2 blues for another set of travelers. Keeps it simple and identified, but then I have all that wire on my truck. For you, you could use all one color, just buy a book of wire markers and number the wires. Naturally don't use white, gray or green

 

[mike93lx]

I know what you mean. I would run black for the common and 2 reds for one set of travelers and 2 blues for another set of travelers. Keeps it simple and identified, but then I have all that wire on my truck. For you, you could use all one color, just buy a book of wire markers and number the wires. Naturally don't use white, gray or green

I like the red and blue idea. I can buy 150' coils of each, so there isn't a ton wasted. Maybe I'll get lucky and the runs will be shorter... Digging this weekend and getting the pipe run

 

[Terry D]

I like the red and blue idea. I can buy 150' coils of each, so there isn't a ton wasted. Maybe I'll get lucky and the runs will be shorter... Digging this weekend and getting the pipe run

.

I like the red and blue idea. I can buy 150' coils of each, so there isn't a ton wasted. Maybe I'll get lucky and the runs will be shorter... Digging this weekend and getting the pipe run

 

[Terry D]

Dont know what happened there, was trying to reply. Since your not pulling it off of individual spools, the main thing is to not end up with a mess of tangled wire. If you could have 3 people doing it, that would be best. On way is to stretch them all out and tape them together. They will not get tangled. But dont let them go in the conduit taped. As you get to each wrap of tape, remove it before it goes in the pipe.

 

[mike93lx]

Dont know what happened there, was trying to reply. Since your not pulling it off of individual spools, the main thing is to not end up with a mess of tangled wire. If you could have 3 people doing it, that would be best. On way is to stretch them all out and tape them together. They will not get tangled. But dont let them go in the conduit taped. As you get to each wrap of tape, remove it before it goes in the pipe.

Appreciate that advice. I was thinking I would pull out the runs all together on my driveway and then respool it. That way I have equal length runs and I'm not trying to pull off a bunch of different spools.

The wire runs won't be for a bit as the pool decking has to be done and then I have to build the shed.

 

[sparky 1971]

You can do it however you want, but I find 1/2" pictures absolutely miserable to work with. The only thing I use it for is to sleeve UF out of the ground. 3/4" would be much better.

Edit. It's obviously meant to be pvc, not pictures.

 

[mike93lx]

You can do it however you want, but I find 1/2" pictures absolutely miserable to work with. The only thing I use it for is to sleeve UF out of the ground. 3/4" would be much better.

Thanks. Already decided to move up to 3/4

I called a local supply house and got quoted under $4 a piece for 3/4, which is half what I was expecting to pay at HD.

 

[jlv03]

How reliable does it need to be? For something like this I'd at least consider either some Wi-Fi switches or Lutron switches with Pico remotes.

 

[mike93lx]

How reliable does it need to be? For something like this I'd at least consider either some Wi-Fi switches or Lutron switches with Pico remotes.

It isn't for anything critical, just lighting. One is for lights on a shed, the other is planned for landscape lighting.

I didn't look at lutron's offerings for some reason. I already grabbed the conduit but haven't started digging. The wire will cost over $100, so some lutron will be cheaper and it will allow me to get the switch indoors instead of on the 3 season.

It's an extra 20 feet of digging beyond what I have to do for supply, so no big deal (lol... Boy was I wrong...) , but I'll look some more at it

 

[mike93lx]

How reliable does it need to be? For something like this I'd at least consider either some Wi-Fi switches or Lutron switches with Pico remotes.

It took me 5 hrs to dig about 20 feet of trench through this damn clay. I would have to dig another 20ish to do wired switches.

Screw everything about that.

Wireless is the right answer

 

[exranger06]

I just realized I am missing a wire. Can someone confirm?

1 egc
1 neutral
1 line (to supply both switches with constant power)
2 travelers for switch 1
2 travelers for switch 2

So to do a pair of remote 3-way switches, I need 7 wires including a neutral, not 6.

The run is reasonably straight, but I will have at least two 90's and a 45, if I can't curve the conduit. I'm planning to use stranded, but at 7 #12's, 1/2" pvc is starting to feel small, no? Feels like 3/4 would probably be worth it, dropping the fill from 33% to 18%. Thoughts and opinions?

Are you talking about the run from the house to the shed? You'll need:
2 constant hots (you said it's a MWBC, so 2 hots. If it's just a single 20A circuit, then 1 hot)
1 neutral
1 EGC
2 travelers for switch 1
2 travelers for switch 2
1 switched hot for switch 1
1 switched hot for switch 2
Looks like you were forgetting about the switched hots. You'll have 10 wires total, which means 1/2" PVC wouldn't even be big enough anyway (if you're using #12 stranded wire. If you use #12 solid wire, it's technically big enough, but just barely.)

 

[mike93lx]

Are you talking about the run from the house to the shed? You'll need:
2 constant hots (you said it's a MWBC, so 2 hots. If it's just a single 20A circuit, then 1 hot)
1 neutral
1 EGC
2 travelers for switch 1
2 travelers for switch 2
1 switched hot for switch 1
1 switched hot for switch 2
Looks like you were forgetting about the switched hots. You'll have 10 wires total, which means 1/2" PVC wouldn't even be big enough anyway (if you're using #12 stranded wire. If you use #12 solid wire, it's technically big enough, but just barely.)

It was going to be two conduits, one for the switches and a separate for the supply. This post was just to address the switches since the supply is very simple.

Now it is one for supply (4-#10 thwn) and wireless switches. Digging sucked and the switch line would have needed a separate trench to save another 7x100ft of wire

 

[FordTruckWench]

1 switched hot for switch 1
1 switched hot for switch 2
Looks like you were forgetting about the switched hots.

There's no reason for the switched hots to be together with the travelers. They go in opposite directions, i.e. the travelers come in from the other building, connect to three way switches, and the resulting switched hots head to the light fixtures.

 

[Terry D]

Are you talking about the run from the house to the shed? You'll need:
2 constant hots (you said it's a MWBC, so 2 hots. If it's just a single 20A circuit, then 1 hot)
1 neutral
1 EGC
2 travelers for switch 1
2 travelers for switch 2
1 switched hot for switch 1
1 switched hot for switch 2
Looks like you were forgetting about the switched hots. You'll have 10 wires total, which means 1/2" PVC wouldn't even be big enough anyway (if you're using #12 stranded wire. If you use #12 solid wire, it's technically big enough, but just barely.)

You can only put (8) #12;s in a 1/2" PVC conduit, it does not matter if they are stranded or solid. But I would not even try to attempt that. Plus the light fixtures are down on the shed, no reason to have both sets of commons at the house. Plus where would you connect them. The switched hots are connected to the commons on the 3-way switches at the shed. The 3-ways at the house has the constant hot connected to the common

 

[exranger06]

There's no reason for the switched hots to be together with the travelers. They go in opposite directions, i.e. the travelers come in from the other building, connect to three way switches, and the resulting switched hots head to the light fixtures.

You can only put (8) #12;s in a 1/2" PVC conduit, it does not matter if they are stranded or solid. But I would not even try to attempt that. Plus the light fixtures are down on the shed, no reason to have both sets of commons at the house. Plus where would you connect them. The switched hots are connected to the commons on the 3-way switches at the shed. The 3-ways at the house has the constant hot connected to the common

I was originally thinking that since the power "originates" at the shed, he'd have the feed/constant hot connected to the switches in the shed, since, in a 3-way circuit, you usually connect the constant hot to the switches that are closest to the feed. It didn't occur to me to run the constant hot back to the house and connect to the house switches first. But yes, it does make more sense to do it that way.
And regarding the conduit fill: I was just going by Southwire's conduit fill calculator: https://www.southwire.com/calculator-conduit I didn't verify it in the NEC.

 

[mike93lx]

I was originally thinking that since the power "originates" at the shed, he'd have the feed/constant hot connected to the switches in the shed, since you usually connect the constant hot to the switches that are closest to the feed. It didn't occur to me to run the constant hot to the house and connect to the house switches first. But yes, it does make more sense to do it that way.

That wouldnt work well in this application based on where the switches were going to be and how I want to feed the shed.

I am running #10 to the shed to deal with the length. That will feed a bunch of receptacles and the lighting circuits. All I wanted to do was control two lighting circuits back at the house, which will be in a totally different location than the power feed is originating from, hence the two conduits.

Either way, the switches are no longer an issue at all as I am going to do them with wireless. I have just a single 3/4 conduit that will get four pieces of #10 thwn.

 

[exranger06]

That wouldnt work well in this application based on where the switches were going to be and how I want to feed the shed.

I am running #10 to the shed to deal with the length. That will feed a bunch of receptacles and the lighting circuits. All I wanted to do was control two lighting circuits back at the house, which will be in a totally different location than the power feed is originating from, hence the two conduits.

Either way, the switches are no longer an issue at all as I am going to do them with wireless. I have just a single 3/4 conduit that will get four pieces of #10 thwn.

Understood. I originally thought the feed to the shed and the switch wiring were going in the same conduit, and like I said, assumed the shed switches were going to be connected to the feed first. I guess you can just disregard everything I said in this thread lol.

 

[mike93lx]

Understood. I originally thought the feed to the shed and the switch wiring were going in the same conduit, and like I said, assumed the shed switches were going to be connected to the feed first. I guess you can just disregard everything I said in this thread lol.

Done

Either way, I appreciate the interest and time. I have a lot to learn and discussions like this help

 

[jlv03]

It took me 5 hrs to dig about 20 feet of trench through this damn clay. I would have to dig another 20ish to do wired switches.

Screw everything about that.

Wireless is the right answer

Just curious, what kind of wireless?

 

[mike93lx]

Just curious, what kind of wireless?

I have had great luck with lutron, so I'm probably going to end up with Pico, on your suggestion.
I want something with real switches and not reliant on an app. I also don't need, or want, Google/Siri integration, at all.

Worst case, the remote stops working, I can just walk out to the shed and flip the wired switch

Additionally, wireless will actually be cheaper too.

 

[alfredeneuman]

You can only put (8) #12;s in a 1/2" PVC conduit, it does not matter if they are stranded or solid. But I would not even try to attempt that.

The NEC says (9) #12. But I agree, it's next to impossible so don't even try.

 

[mike93lx]

The NEC says (9) #12. But I agree, it's next to impossible so don't even try.

Should be a lot easier if you put the wire in as you assemble the conduit.





I jest, I jest.

 

[Terry D]

The NEC says (9) #12. But I agree, it's next to impossible so don't even try.

(9) #12's is for EMT. Schedule 40 PVC is only (8) #12's

 

[Terry D]

Should be a lot easier if you put the wire in as you assemble the conduit.





I jest, I jest.

That is not a good practice to do, plus it is a NEC violation.

300.18

Raceway Installations

Raceways other than exposed raceways or busways that have hinged or removable covers must be installed complete between outlet, junction, or splicing points before the conductors are installed. Three exceptions are: (1) for prewired assemblies, (2) when necessary for the installation of utilization equipment, and (3) short sections used for protection from physical damage. There is a restriction on the use of welding

 

[mike93lx]

That is not a good practice to do, plus it is a NEC violation.

300.18

Raceway Installations

Raceways other than exposed raceways or busways that have hinged or removable covers must be installed complete between outlet, junction, or splicing points before the conductors are installed. Three exceptions are: (1) for prewired assemblies, (2) when necessary for the installation of utilization equipment, and (3) short sections used for protection from physical damage. There is a restriction on the use of welding

I know. Read my whole post

I almost mentioned staggering splices in the conduit to reuse existing leftover pieces of nm, but thought that might be too much

 

[wyliesdiesels]

That is not a good practice to do, plus it is a NEC violation.

300.18

Raceway Installations

Raceways other than exposed raceways or busways that have hinged or removable covers must be installed complete between outlet, junction, or splicing points before the conductors are installed. Three exceptions are: (1) for prewired assemblies, (2) when necessary for the installation of utilization equipment, and (3) short sections used for protection from physical damage. There is a restriction on the use of welding

 

[Terry D]

Lol, I didn't see the bottom part