Switch for LV undercabinet lights: please help before I take the bridge.

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Old 09-07-09, 08:20 PM
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Switch for LV undercabinet lights: please help before I take the bridge.

New here, so pardon the idiotic mistakes I'm making. Here's the scenario:

I patched a 12-3 to my laundry room by cutting into that rooms outlet circuit. This same 12-3 from the service box is also for family room outlets. I used a branch of 12-3 simply because it's what I had. In any event this single branch of 12-3 is going to a switch to control two transformers for undercabinet low voltage lighting. No matter how I wire it, it trips the breaker. It should be noted I capped and do not use the hot red wire (the red is the family room power).

I have a hot black, neutral white, ground, and two sets of wires coming from the transformers, a "ribbed" and a smooth on each transformer. The lights can be hardwired or you can throw their cheap outlet on them. It says if hardwiring call an electrician, no instructions beyond that. I did notice they say to put the "ribbed" wire in the outlet so that it's the polarized end of the plug if you choose to plug them in. Also, they have a switch and the ribbed wire is uncut if you use the switch.

How the heck do I wire this? No matter what I do the lights are ON when the switch is OFF, and then when I turn it on it goes off and trips the breaker. It is not a GFI and is for lighting where my wife folds clothes. I was running black to the post in the up position, along with the smooth wire tied to that, and the ribbed wire tied to the white at the lower pole, and grounded. All sorts of crisscrossing produced nothing different as I was then into just experimenting. Nothing else is on in that room so there is not much of a load. I also checked and don't see any crossed wires going to the lights.

Thanks in advance. Very frustrated. I have too many hours into this now to call someone, and I enjoy learning, but ready to suck on the gas pipe soon if I can't figure it out.
 
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Old 09-07-09, 08:26 PM
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You only want to wire the hot wire on the switch. The ribbed wire is return path for the current and should not be switched.

It concerns me when it sounds like you have zip cord or something similar going to the switch.

Can you tell or post a link to the LV lights you are using?
 
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Old 09-07-09, 08:34 PM
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First off you my not tie into the laundry circuit (IE: the one that powers the washer and dryer. You may tie into the circuit that is running the family room.

As PC posted you need to only interrupt the hot wire. The ribbed wire should only be connected to the white wire. Also, any splicing needs to be in a junction box and the cord that came with the light are not allowed to be run in a wall.
 
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Old 09-08-09, 05:00 AM
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Originally Posted by pcboss View Post
You only want to wire the hot wire on the switch. The ribbed wire is return path for the current and should not be switched.

It concerns me when it sounds like you have zip cord or something similar going to the switch.

Can you tell or post a link to the LV lights you are using?
Thanks. Then are you saying to put the smooth wire to the transformer on the upper screw, hot black on the lower, and ribbed wires tie into the neutral white wire? Have to admit I didn't do that.
 
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Old 09-08-09, 05:05 AM
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Originally Posted by Tolyn Ironhand View Post
First off you my not tie into the laundry circuit (IE: the one that powers the washer and dryer. You may tie into the circuit that is running the family room.

As PC posted you need to only interrupt the hot wire. The ribbed wire should only be connected to the white wire. Also, any splicing needs to be in a junction box and the cord that came with the light are not allowed to be run in a wall.
Thank you. Why not tie into the laundry circuit? Load? I can certainly easily cut into the family room hot wire. If I understand you correctly I'm to tie into the hot/neutral wires in a separate junction box? If so, then I have to put that box in the wall don't I? Unless I put it on top of the cabinet. Now I know why electricians are paid well and in demand. I've wired my whole basement without a hitch but that was open walls, new circuit, so pretty straight forward. This was perplexing.
 
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Old 09-08-09, 06:12 AM
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The electric code says that the laundry circuit shall have no other outlets. Tying in your lighting would violate this.

Yes your splices need to be made in permanently accessible junction boxes. The splices cannot be buried in the wall.

To repeat what Ben said, you cannot run the low voltage wire in the wall. You should not be connecting it to a switch. You would need to use another method like non-metallic cable from the switch to the low voltage wiring.
 
 

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