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#34295 02/07/04 01:40 PM
Joined: Aug 2001
Posts: 545
A
aldav53 Offline OP
Member
Regarding the church I am upgrading wiring on is the lighting dimmer pack calls for 2-20 amp at 120v circuits input, and 4-channels output at 1200 watts 120v each. That output would seem to be a bit high for just 2-20a circuits?


The Golden Rule - "The man with the gold makes the rule"
#34296 02/07/04 05:04 PM
Joined: Nov 2003
Posts: 269
E
Member
The lighting would be considered a continuous load so each 20A circuit would be limited to 1920watts or 3840 watts for two.


John
#34297 02/08/04 01:09 PM
Joined: Aug 2001
Posts: 545
A
aldav53 Offline OP
Member
electricman2,
It seems that the 1200 watts per channel (2 channels per circuit) would put it at 2400 watts output, over the 1920 watts, right?


The Golden Rule - "The man with the gold makes the rule"
#34298 02/08/04 01:27 PM
Joined: Jan 2002
Posts: 10
N
Member
Perhaps if these dimmers were fed via breakers listed for 100% continuous load?

#34299 02/10/04 05:57 PM
Joined: Nov 2003
Posts: 269
E
Member
I don't know how the system is set up. It may be possible to split it up into 3 circuits.


John
#34300 02/10/04 07:57 PM
Joined: Sep 2003
Posts: 650
W
Member
You are going to have to double check the data/instruction sheet for the dimmer packs. It may very well be that they are rated for 1200W per channel, 4 channels, but at less than 3600W _total_ output at any one time. Or it may be the case that being on a dimmer pack lets one consider the lighting 'non continuous'...or it may be the case that the dimmer pack has a built in controller that limits the output power to be less than 3600W for > 3 hours. Or it may be an error in the listing.

I would certainly double check prior to putting the dimmer pack on OCPD > the 20A listed in the instructions. It is possible that the unit is listed only for use on a 20A circuit.

-Jon

#34301 02/11/04 09:54 AM
Joined: Jun 2001
Posts: 161
M
Member
Check out the listing and instructions since many dimmers are indeed rated for 100% of their rated load. Also, since these sound like thyrister based dimmers you may also need to install a 200% neutral. Check out NEC section 520 for the details.


Mike Wescoatt
#34302 02/11/04 11:05 AM
Joined: Aug 2002
Posts: 35
S
Member
What kind of dimmer pack is this? I sounds like one of the el cheapo dj models. The instructions read, "Just plug it into to different outlets on different breakers and you are good to go!" If you are modifing it for fixed wiring you are probally violating it's listing (if it is not an unlisted taiwan knockoff).

Most dimming kit has OCPD rated at 100% with the assumption that in a large installation that all dimmers are not pulling 100%. For example a 96 dimmer rack with 20 amp dimmers can be feed from a 400amp three phase service as per the manufacturer.

As for your dimmer, if you open it and take a look, it is two seperate devices. Each 20 amp dimmer has a scr or two, a couple of chokes and a firing circuit. Technically, you could load the each dimmer up to 100%, but if you plan to do this full time the entire installation needs to support it (100%rated OCPD in the pannel). Do not put bigger breakers in the pannel, stick with the 20amps.

SD

SD


SD
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