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Discussion Starter #1
We have a 20 amp breaker that currently powers one basement light from an upstairs switch. We're trying to install a second light on the same switch at the top of the stairs. We know we have the switch set up right because the light at the top of the stairs does come on, it just won't come on to full brightness and/or it flickers. Can you provide some insight for us or things we should check/re-check? Thanks!

kyrna
 

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How did you wire the new switch and light.
If the light will not come to full brightness, then you have something wired wrong.
 

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Was there only a black and a white connected to the switch?
 

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Discussion Starter #5
There was only a black and a white connected to the switch? What does this mean? We have double, triple and quadruple-checked the wiring and it is correct as is. Just can't figure out why a 20 amp can pump out enough juice to power to lights. I'm anxious to learn what having just the black and the white means. Thanks for the posts! kyrna
 

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if there is only black and white wires on switch and no other wires in box, than you are missing a neutral. It is probably at the old light. The black and white wires are only switch legs.
 

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Discussion Starter #7
Isn't the white wire the neutral wire? Why would we need another neutral wire?
We've wired it according to the diagram in an electrical manual for "How to wire single pole switch with switch controlling two lights." Can you be more specific in what we should do or what we're missing since our set up mirrors the diagram?
 

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No it is not a neutral in this case. You can NOT add a new light from the switch. You must run it from the old light or run a new 3 wire+ground cable from the old light to the new switch.
 

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the reason their is only a black and a white there is because, they just ran a "switch leg" to the switch. typically what happens is, they bring the feed to the light box, then run 1 2 wire down to the switch, they send 120v down to the switch on the white wire and use the black as the switched leg.
 

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Let me post a photo what the switch loop look like.,




And please study the diagram carefull and what you did add a second luminaire at the switch loop side which the result is series connection that why the light bulb is not very bright at all or flicker if you have CFL there.

The only way you can slove is follow Joed's comment on that and I will say the same thing as Joed will tell ya eitherway will work but I rather make a arrangment to three way switch set up due you will may make a finshed basement not too far away from your plans so it will be wise to do that and at the same time address the issue with the upper and lower luminaires.

Merci,
Marc

PLEASE NOTE: the diagram is correct but the colour format is not correct it should have remarked white to supply black conductor.
 

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Psst! The switched hot coming back to the light may not be white even if taped black. So the unswitched hot going to the switch has to be the white wire.

For those cities that have adopted the 2011 National Electric Code, switch legs need 3 wire cable where white is really a neutral. Then it doesn't matter whether red or black is the unswitched or switched hot. The white neutral then solves the OP's problem of powering the new light by stringing wires to the switch box in question.
 
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Yep. The diagram will function but is not wired to code. The black and white to the switch must be reversed at the fixture.
 

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Discussion Starter #14
Thanks for all the help. We're in the process of re-doing it now with the new light positioned in a different spot. I think we've got it now. Let you know if we don't.
 
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