Need some help with wiring (House)

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zakimodo

zakimodo

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Hi All

Not a shop, but it's the next best place, the bathroom. My wife and I are expecting our 3rd kid, to make room for her i am finishing our basement. I am just finishing up my rough electrical and have once circuit that I can't figure out how to wire. (my brain is good with automotive wiring, but not so much for house wiring)
What I have to wire
-3 lights
-One of these is a light/ fan combo. The fan will be on a separate switch from the lights.
-Line power is at the light furthest from the switch (switch is the last item in the circuit)
-Image is a rough representation of the location of the light and switches. The lines connecting them are how I would like to route cable if possible.
Any input or suggestions would be appreciated.
Thanks in advance

Bathroom layout.png
 
Ideally you would want to feed the switches hot and then from the switch run a 12/3 with gnd.
to the fan/light combo then out of the combo with a 12/2 with gnd. To feed light one and three.
 
Green wire is a safety ground and is connected to the green screw on the switches. Sorry I left that out of the picture.
 
cudascott said:
Ideally you would want to feed the switches hot and then from the switch run a 12/3 with gnd.
to the fan/light combo then out of the combo with a 12/2 with gnd. To feed light one and three.
Click to expand...

Light circuits are almost always 14 guage wire, which is good for a 15 amp breaker! 12 guage wire is usually reserved for wall plugs, and using 12 guage wire for light circuits will always confuse the inspector, and is overkill for almost any common household lighting!!
 
cosgig said:
Light circuits are almost always 14 guage wire, which is good for a 15 amp breaker! 12 guage wire is usually reserved for wall plugs, and using 12 guage wire for light circuits will always confuse the inspector, and is overkill for almost any common household lighting!!
Click to expand...
Sounds like you need a new inspector
 
Bathroom layout.png

I'd run it like this. (ignore your original fine black line). Sounds like you are planning to use existing power feed. I would stay with same size as that 12 or 14. use 2 w/grd from light 2 to light 3. wrap a couple inches of black tape on white wire at switch and fan to indicate it is hot.
 
If it is a 20 amp breaker, then all the wires on that circuit must be 12 gauge. Think if you used 14 gauge on the 20 amp breaker for lights and the light socket shorts out. Then the 20 amp breaker may not pop to save the wire from melting and starting a fire.

Aren't you putting in at least one outlet in that room? I suggest you add one and make it a GFCI.
 
cudascott said:
Sounds like you need a new inspector
Click to expand...

It's not just for the inspector!! If you are going to run 12 guage wire in a lighting circuit, then everything in the circuit needs to be 12 guage 20 amp stuff, including the switches and lights! As a matter of fact, in your typical home improvement store, which 99% of the DIY projects will be purchased, you will not find a single fan/light combo that is rated for a 20 amp circuit and 12 guage wire! Heck, even the wirenuts they provide in the box are for 14 guage wire! Enlighten us as to why a common household lighting circuit would need a 20 amp circuit!!!
 
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In these situations I purchase 3 strand, be it 12/3 wg or 14/3 wg, whatever. The red would be my supply to switch box ( tied into that supply shown at that first fixture ), and black for returns. Using tape to make the red be black where necessary is legal.
 
i think it's stupid to run any 15 amp circuit in a house there cosgig thats my prefrence. please do tell how long you have been an electrician? myself thats all i've ever done
joruneyman wireman local 760 for 22 years your gonna have to pick something else to run off about.
 
cudascott said:
i think it's stupid to run any 15 amp circuit in a house there cosgig thats my prefrence. please do tell how long you have been an electrician? myself thats all i've ever done
joruneyman wireman local 760 for 22 years your gonna have to pick something else to run off about.
Click to expand...
you see you are showing your ignorance when you say that the light has to be good for 20 amps. well the light is the load and can be a .5 amp for that matter
and who gives a rats *** about what size wire nut comes in the box.
 
cudascott said:
i think it's stupid to run any 15 amp circuit in a house there cosgig thats my prefrence. please do tell how long you have been an electrician? myself thats all i've ever done
joruneyman wireman local 760 for 22 years your gonna have to pick something else to run off about.
Click to expand...
15 amp is adequate for overhead lighting.
When wiring a entire home the pennies difference in the wire cost can add up. It's only money though.
 
68gtxman said:
If it is a 20 amp breaker, then all the wires on that circuit must be 12 gauge. Think if you used 14 gauge on the 20 amp breaker for lights and the light socket shorts out. Then the 20 amp breaker may not pop to save the wire from melting and starting a fire.

Aren't you putting in at least one outlet in that room? I suggest you add one and make it a GFCI.
Click to expand...

Yes, outlets are on a separate circuit. The lighting circuit is 15 amp, I am using 14 2/3 wire respectively.
 
I am not an electrician, and will not try to recommend a wiring diagram.
What I will recommend, though, is putting a timer switch on the fan. I remodeled our master bath last year and installed two, for two separate fans. I consider it one of the best upgrades I done! Put it on 30 minutes, take a shower and not have to go back or remember to go back to shut the fan off. I really like it.
C
 
I want to start by recommending you get a proper permit for this work dependent on where you are located. I hope my sketch attaches to this post as this won't make much sense without it. I have never tried to attach a PDF to a post before. If it doesn't feel free to PM me your email address and I'll send it to you.


Light 1

  • Attach the bare copper wire from 2 wire cable “A” to the junction box bonding screw. Connect the free end of that wire to the bare copper wire from 3 wire cable “B”. If there is a bare wire, green wire or green screw identified as ground on the fixture connect it to the bare bonding wires as well.

  • White to white (Include white wire from 2 wire cable “A”, 3 wire cable “B” and white on light fixture)

  • Black on 2 wire cable “A” to Red on 3 wire cable “B” (Caries power to the switches)

  • Black from 3 wire cable “B” to light fixture
Light 2

  • Attach the bare copper wire from 3 wire cable “B” to the junction box bonding screw. Connect the free end of that wire to the bare copper wire from 3 wire cable “C” and 2 wire cable “D”. If there is a bare wire, green wire or green screw identified as ground on the fixture connect it to the bare bonding wires as well.

  • Wrap white wire from 3 wire cable “C” with black tape. This is no longer a white/neutral wire. Connect it to the fan wire on the light/fan fixture.

  • Red to red (Caries power to switches)

  • White to white (Include white on 3 wire cable “B”, 2 wire cable “D” and the light/fan fixture.)

  • Black to black (Include the black from 3 wire cable “B”, 3 wire cable “C”, 2 wire cable “D” and the light wire from the light/fan fixture.
Light 3

  • Attach the bare copper wire from 2 wire cable “D” to the junction box bonding screw. If there is a bare wire, green wire or green screw identified as ground on the fixture connect it to the bare bonding wire as well.

  • White to white

  • Black to black
Switch box

  • Attach the bare copper wire from 3 wire cable “C” to the junction box bonding screw. . Connect the free end of that wire to the green bonding screws on the switches.

  • Red wire will be common to the bottom of both switches.

  • Black wire to the top of the light switch

  • Wrap white wire with black tape. Connect it to the top of the fan switch.
Always remember to run the bare wires so they do not come in contact with the exposed live electrical parts in the box such as connection screws. This will cause the breaker to trip and may cause other damage like burned off wires etc.

I would recommend a deep box for light 2 since there are additional connections needed at that location. Dependent on the codes local to your area, it may not be necessary but it will definitely be more convenient for you.

As was suggested above, a timer on your bathroom fan is a good idea. The timer will directly replace the fan switch but if you chose an electronic timer over a spring wound timer you will need a 4 wire for cable “C”.

Remember, when buying household electrical wire, it always only counts “Current carrying conductors” so a 3 wire means 3 “Current carrying conductors” and the bare ground.
 

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