Neutral on dimmer circuits

[txsparky]

The engineer of the job that I am currently on has spec'd a couple of 3 wire track lights(2 ckt, 1 neutral). Each track circuit will have (5) 250 watt lamps each controlled by 1500 watt dimmers. My concern is, that I have never shared a neutral on track lighting (or a dimmer circuit) and am wondering how the dimmers will perform? What load will the neutral bar on the track see. This a 20 amp rated track.

[ May 25, 2004, 05:51 PM: Message edited by: txsparky ]

 

[steve66]

Re: Neutral on dimmer circuits

I have always been told that you don't want two dimmers to share the neutral on a track. I don't know why, but the lights will flicker or fade in and out, etc. I would have specified a 3 circuit track and used the 3rd circuit as the 2nd neutral.

Steve

 

[jschultz]

Re: Neutral on dimmer circuits

http://www.lutron.com/product_technical/faq.html

Recommendations:
Lutron recommends the following methods to avoid common neutral interaction:
A. Separate neutrals B. Filter choke C. Special Lutron dimmers
Filter Chokes
If it is not possible to run separate neutrals for each phase (e.g. an application with existing wiring), you can use filter chokes to "clean up" the voltage spikes creating the interaction. One filter choke is required for each dimmer. The filter choke makes an audible buzz, so care should be taken to mount it in an area where the noise will not be objectionable.
Filter chokes can be wired in series on either the line side or the load side of the dimmer.

Special Dimmers
If it is not possible to run separate neutrals or use filter chokes to correct the interaction, the following special dimmers are available from Lutron to accommodate common neutral applications:
Model#
NCN-600
NCN-1000
NCN-1500
NCN-2000 Max. Load Capacity
600W
1000W
1500W
2000W
Note: All models are for incandescent lighting and are available in Nova? style only.

 

[txsparky]

Re: Neutral on dimmer circuits

steve66,jschultz,
Thanks alot for the info. and links. I felt like we would experience problems with a shared neutral.

Donnie

[ May 26, 2004, 08:26 PM: Message edited by: txsparky ]