Track Lighting Load Calculation in California

[Fred G]

I am remodeling a ballroom in a swanky California city. The whole dimming system was upgraded with the intent to put the existing 3 wire track system on the new dimming system. Since I can't share the neutral, per manufacturers instructions, I am trying to figure out which calculation I should be using. The engineer is stating a "per linear foot" method. It is my understanding of the code that, that is for feeder/service calculation only and I think it should be actual load calculation with 125% over current protection. Any thoughts?

By the way, I thought this was a calculations area....not just a how do I plug something in area.....

Does anybody know of a good in line load limiter that is not track mounted?
Thanks,
Fred

 

[frizbeedog]

...It is my understanding of the code that, that is for feeder/service calculation only and I think it should be actual load calculation with 125% over current protection. Any thoughts?

Just some points to consider.

410.151(B) Connected Load

....Lighting Track shall be supplied by a branch circuit having a rating not more than the rating of the track.

FPN: The load calculation in 220.43(B) does not limit the length of track on a single branch circuit, and it does not limit the number of luminaires on a single track.

2008

 

[eeRyanC]

Hi Fred,

I'm not sure what you mean - If it is three wire track, don't you have to share the neutral (2 hots, 1 neutral)? Or, are we talking 3-wire fluorescent dimming track heads - that would be odd? Most 2 ckt track that I have seen is 4-wire. I believe that title 24 specifies to treat any number of circuit track as one run (45W/ft) - that is to say that you don't have to count each circuit at 45W/ft. Depending on how long your runs are, you will be able to make use of power trips to limit the energy load. However, based on your post, I am not sure if you are looking for the title 24 energy load or the NEC circuit calculated load. In my experience, code officials have to buy off on use of power trips (line load limiters) for use in NEC calculated load on a per permit basis.

For remote power trips, I think that Lightolier makes a remote power trip cabinet but I have never used it. Alternatively, title 24 does allow you to use the circuit breaker as the current limiter for the purpose of energy calcs.

Hope this helps! Sorry about the lack of code references, but should at least give you a starting place.

 

[scotteng]

Track Current Limiters

Track Current Limiters

Fred,

I thought I would throw my 2 cents in this discussion since I am working on the very topic tonight...

NEC track calcs for line voltage track without current limiting devices is 150VA per every 2 lineal foot or fraction thereof. If you have multi-circuit track, the load is considered divided equally. For example: 18' of single circuit track is (150VA*18lf)/2lf = 1350VA. If that track is 2-circuit track, each circuit is only 1350VA/2=675VA. If that track is 3-circuit track, each circuit is only 1350/3=450VA. I'm not aware of a load calc for track lighting based on a breaker rating.

Title 24 is a very different game. For line voltage track without current limiters, you are stuck at 45W/lf. If you install current limiters, you get to use the greater of either a) 120V X CL rating or 15W/lf. LC&D makes a panel called the Silver Bullet which they have documentation from the California Energy Commissison stating that their panel meets the intent of Title 24. If you are working in a "Swanky" city, then their building department is probably going to be looking at your Title 24 calculations just as intently as your NEC calculations.