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Jerome A.
3 way switch multiple lights

Could someone point me in the right direction. I want to install 4 lights between 2-3way switches, power through a switch. Some diagrams have 1 scenario, some have another.

1 diagram says use 12/2 from the panel to the first switch, 12/3 from switch to first light, 2 - 12/2 cables from first light to each additional, then 12/3 from last light to last 3 way switch.

Other diagrams say run 12/2 from panel to first switch, 12/3 from first to second switch, then 12/2 black to white connections between all fixtures (with grounds).

Is this just depending on the situation or material cost?
Thanks for your wisdom!
Jerome A.

NEC
Re: 3 way switch multiple lights

Your first diagram/description will not work.

The second one will.

canuk
Re: 3 way switch multiple lights
Quote:

1 diagram says use 12/2 from the panel to the first switch, 12/3 from switch to first light, 2 - 12/2 cables from first light to each additional, then 12/3 from last light to last 3 way switch.

NEC....... if I'm not mistaken this does work.
The other 12/2 is just extending the travellers between the switches.

example ........

black ( 12/3 switch A ) to white ( 12/2 ) to white ( 12/3 swich B )

red ( 12/3 switch A ) to black ( 12/2 ) to red ( 12/3 switch B )

white ( 12/3 switch A ) to white ( 12/2 from panel feed ) to white ( at first light )

black ( 12/3 switch B ) to black ( last light ) .

Quote:

Is this just depending on the situation or material cost?

Yep .... depending on the distance between the 2 switches can save some cost.

....... but then and again what the heck do I know.;)

NEC
Re: 3 way switch multiple lights

Ohhhhhhhhh! My bad! I missed the 2 12-2's between the fixtures.

Question though:

Why on earth would you want all of that wire and make-up at the fixture locations?

canuk
Re: 3 way switch multiple lights
Quote:

Why on earth would you want all of that wire and make-up at the fixture locations?

At least 2 .... but I would agree.
I guess it depends on the situation.
If it was easier access to run all the wiring up into an attic then this would probably be the ticket........ just a guess.;)

Jerome A.
Re: 3 way switch multiple lights

Thanks for the responses. My situation is open access to ceiling joists with holes through them to run wires. The total run is about 60ft between switches.

JLMCDANIEL
Re: 3 way switch multiple lights

See if the drawing below helps. Ground wires are omitted for clarity but must be installed.
Jack

Jerome A.
Re: 3 way switch multiple lights

Jack, Thanks for a diagram I can understand. This seems like the more logical approach to take.
Thanks again all!

canuk
Re: 3 way switch multiple lights

Yep ..... Jack's diagram is the simplest but still requires the 60 ft run of 12/3 between switches.
Compared to the other method of 2 runs of approx. 8 ft of 12/3 and the 60 ft run of 12/2 ...... if the cost saving was worth it.

By the way ..... why the use of 12 ga. wire for the lights?
If this is a dedicated circuit run from the panel then consider using 14 ga. 15 amp for this light circuit ....... there will be a savings there.

Just a thought.

NEC
Re: 3 way switch multiple lights

Actually Jacks diagram does not meet the requirements of the NEC. That white in the three wire must be reidentified and used as a hot only and not a switch leg or traveler. (Sorry, no article reference as I do not have access to a code book at the moment.)

For the sake of anyone having to trouble shoot in the future I would wire it as 99% of electricians would. I would take a three wire between the two switches and either take the neutral and switch leg from the feed box or from the second switch to the fixtures

That way the white can either be reidentified and used as the hot to feed the common on the second switch. Or as a neutral if the fixtures are being fed from the second switch.

I could show you a way to feed the one switch and take a two wire between the two switches and also a two wire to the first light, the remaining lights and from the last light down to the second switch. It is legal and you end up with both hot and neutral at both switches. However, there are no true travelers in this switching arrangement and I would feel sorry for someone trying to figure it out in the future.

Jerome A.
Re: 3 way switch multiple lights

Soooo NEC are you saying it is like Jack's diagram except the power for the lights comes through the 2nd switch? I'm just trying to simplify it yet do it properly. I'm trying not to confuse myself here :)

Jerome A.

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