Light(s) Wiring question

[smalltown]

I have been searching, but depending how you label this configuration I see different answers.

I am using multiple switches to control multiple LED fixtures. I had intended on pulling in a hot and a neutral for each fixture, but got wondering is it permissible to run a single neutral from the service panel to the first junction box then start feeding the neutral from there to the other fixtures ?

Here is a drawing of what I am talking about, although I will be using more switches, and LED lights.
I am pulling in 12 gauge THHN using a single circuit breaker.
I calculate with all the LEDs lit I will draw 6 amps.

 

[ard]

If you might ever want to install a zwave (or other) remotely controllable switch, you will want a neutral in the switch box....just FYI

 

[pattenp]

NEC requires a neutral in switch boxes unless box is conduit fed where a neutral can be later added.

 

[smalltown]

pattenp Yes it will be in conduit

 

[cybrdyke]

I'm confused.

If it's in conduit...
are you saying you're going to run hots in one conduit and neutrals in another?

CD

 

[smalltown]

I was going to wire from left side of the service panel through conduit to switch box, and the multiple switches. From the switches up to my first pull box where it would be met by a neutral wire that will exit the service panel top in conduit, and then all would proceed together.

I was hoping to avoid passing all the neutrals (if I have to wire each one at this point) through the switch box with the hots. But if I could run just one neutral that would not be an issue.

 

[PCustoms]

I was going to wire from left side of the service panel through conduit to switch box, and the multiple switches. From the switches up to my first pull box where it would be met by a neutral wire that will exit the service panel top in conduit, and then all would proceed together.

I was hoping to avoid passing all the neutrals (if I have to wire each one at this point) through the switch box with the hots. But if I could run just one neutral that would not be an issue.

Run 1 hot, 1 neutral to the box. Hot gets tied to the switches, neutral goes to the lights. There isn't any "all the neutrals"

 

[PhysicsDude]

No reason to pull multiple neutrals in the same box or conduit for the separate lights. Regular switches don't touch the neutrals, so strictly speaking you don't need to have the neutral in the switch box, although its still a good idea to run one even if you just cap it off in the back of the box.

 

[smalltown]

So I'm thinking since I am using the same breaker for all the lights that the real issue is the total current on the single neutral ?

 

[PCustoms]

So I'm thinking since I am using the same breaker for all the lights that the real issue is the total current on the single neutral ?

Uuum what?

If you have all the lights on a single breaker, how do you expect to get a higher total current on the neutral?

How many lights are you using, what is their total draw (Hint: LED are low!) and what wire are you using? IIRC, by code, lights can only be sized to 80% of the breaker size, so for a 15A breaker and 14 gauge wire you can run a max of 12A worth of lights.

Your hot wire off the breaker can only supply 15A, period. doesn't matter if you feed a dozen switches with that, if you turn everything on and pull more then 15A the breaker will trip. The single neutral feeding the light bank is still part of that same circuit.

 

[ddawg16]

You still have to get a neutral to the lights.....

I personally don't care for the switched neutral concept....that is how my house was wired originally....hot and neutral went to each fixture....then the neutral was wired to the switch.

So back to the issue, you want to just daisy chain the neutrals to the lights. Yea, you can do that.

But I would only do it for each bank.

Say you have 4 lights per switch....I'd run the neutral with the hot to that bank. I wouldn't pull the neutral from the other bank.

As you start wiring it, I think you will find trying to use just one neutral for the whole mess is not going to save you anything.

 

[smalltown]

Posting things can be difficult to get a point across.
What I am trying to say is if I wire as intended:
Wire from a single breaker.
One hot lead daisy chained to a number of switches.
Then run all those switched leads to separate led lights.
Wire a single neutral from the service panel, and daisy chain the neutral up in the attic area light to lights.
Since I would have one neutral coming back to the service panel I imagined the real issue was the total current on the neutral ?

 

[PCustoms]

Since I would have one neutral coming back to the service panel I imagined the real issue was the total current on the neutral ?

Why do you think the total current on the neutral is going to be so high? I re-read your OP, you calc 6a of draw. Your neutral only has to support 6A.

Unless you are coming up with some other wiring scheme I am not picturing.

How many light fixtures? I assume each bank will be on a conduit run?

I would run a hot and a neutral to the box. Pull wires (hot, neutral and ground) to the first light in each bank. Tie all the grounds together in the box, tuck them in the back. Th tie all the neutrals together and stuff them back there too, if you ever add a smart switch or occupancy sensor you will need them. Now pigtail each switch to the hot line from the breaker and tie in the feed to each bank.

Done

 

[PCustoms]

Oh, and why pull 12 awg if you only have 6a load?

If you have a bunch use it, but 14 will pull easier and stuff into the boxes better.

 

[smalltown]

Yes I already have rolls of 12 Gauge THHN

It's not that I think the current will be high at all.
Since I am using LEDs the current will be relatively low, but nevertheless all on the single neutral. I thought that issue was what others were concerned about.

Yes I will wire that way. 13 lights 10 switches all conduit.
Overkill maybe, but I will sleep at night knowing the mice are not gnawing away in the garage attic space.

 

[CJ7VFR]

Yes I already have rolls of 12 Gauge THHN...

If you are going to be using the 12 AWG wire for everything, you might want to think about putting in a 20 Amp breaker for your circuit, if you are not already doing that.

You may not need the extra amps now, but if you put in the 20 Amp breaker at the start, you could add in a convenience receptacle at any of the switch boxes down the road, and you would not have to worry as much about it.

I like to add in receptacles where I have light switches in work areas because I always seem to need to plug in a vacuum or a shop light or something right near where the switches are. Having a receptacle there, just for that convenience, is great.

Jim