track light load and NEC

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tvo

Member
Hi,
I am still confuse about calculate the load for Track Light. According to NEC, it require 150va for every 2 feet of track. If I have a 30 feet track light with 10 head. Each head is 100 watt. The total load for this track is 1000w. 1. Can I run 1 20a circuit for this track?
2. Or by NEC code, 150va for every 2 feet. THat make the total load of this 30 feet track = 2250va. It's over 1920va, so that mean I have to run 2 circuit?
Can someone give me advice or example on this? Or give me a link to this question.
Thank a lot in advance,
Tvo
 

bob

Senior Member
Location
Alabama
Re: track light load and NEC

tvo
You must use the 150 va for every 2 ft.
Total as you said is 2250 va. The reason is because after you leave the owner can add
additional bulbs.
 

bphgravity

Senior Member
Location
Florida
Re: track light load and NEC

First of all, you are combining two different rules to perform your calculation. Lets do one part at a time.

I am supposing that this is for a commercial installation and not a dwelling.

First rule: For the service calculation, you apply the 150va per 2' of track rule. Also, if this is a continuous load it must be increased 25%. Example: 30'/2ft = 15 x 150va x 1.25 = 2,813va to be applied to the service.

The second rule would be for branch circuits: A single 20A circuit is good for 1,920va. (20A x .8 =16 x 120v = 1,920va.) Next take the total va and divide by the load of a single lamp: 1,920va/100watt = 19 fixtures allowed.

So for your example, you can easy supply 10 fixtures and even add 9 more if you desire. :)
 

steve66

Senior Member
Location
Illinois
Occupation
Engineer
Re: track light load and NEC

Bryan:

I don't think you have to add another 25% to track lighting. Basically, it's already included in the 150VA/2 ft. The example in the handbook supports this :)

Steve
 

shaun

Member
Re: track light load and NEC

Steve's previous message:
Bryan:

I don't think you have to add another 25% to track lighting. Basically, it's already included in the 150VA/2 ft. The example in the handbook supports this

Steve


Steve: what handbook did you see that in?

Shaun
 

bphgravity

Senior Member
Location
Florida
Re: track light load and NEC

Originally posted by steve66:
I don't think you have to add another 25% to track lighting. Basically, it's already included in the 150VA/2 ft. The example in the handbook supports this
I am quite certain ANY continuous load applied to a service per 230.42 shall be increased by 25%, including lighting, show windows, and track lighting. See Example D3 of the 2002 NEC. The handbook is not the final authority of NEC requirements. :p
 

steve66

Senior Member
Location
Illinois
Occupation
Engineer
Re: track light load and NEC

Yes, the example in D3 does show adding 25% to a track lighting load. But I am not convinced. The example in the handbook does not add 25% (62.5 feet of track adds 4800VA).

The handbook is not the final authority of NEC requirements.
Yes, but lets not forget the intro to Annex D!!!
Code:
 The annex is not a part of the requirements of tehis NFPA document but is included for informational purposes only.
My opinion is (and I could very well be wrong) that the extra 25% only applies to actual connected loads. Table 220.3(A) and 150VA/ 2ft for track lighting are not actual connected loads. If they wanted the 150Va to be 187.5, why not just say add 187.5 VA for each 2 feet.

Steve
 

bphgravity

Senior Member
Location
Florida
Re: track light load and NEC

Originally posted by steve66:
The annex is not a part of the requirements of tehis NFPA document but is included for informational purposes only.

If they wanted the 150Va to be 187.5, why not just say add 187.5 VA for each 2 feet.

To start with, are you saying that you would rather take the example of a separate reference than the one actually in the code itself?
For your second point, not all loads are going to be contiuous so the code can not automatically add it in as you suggest. My calculation assumes a continuous load considering it is for a commmercial occupancy. Is it possible that the example in the handbook is not a continuous load? In general, the code provides the most basic and stripped requirement and provides rules for additonal considerations. :)
 

steve66

Senior Member
Location
Illinois
Occupation
Engineer
Re: track light load and NEC

Bryan:

I can't imagine a track lighting installation that I wouldn't call continuous. Dwelling, commercial, or any other occupancy. If it might be on for 3 hours, it is continuous.

But I still think 150VA/2 ft is not a actual connected load. And I believe the extra 25% is only for actual connected loads. If we knew there were actually a 150W lamp every 2 feet, then yes, multiply 150 by 1.25.

I think this also applies to the unit loads in table 220.3 (A).

Steve
 

bphgravity

Senior Member
Location
Florida
Re: track light load and NEC

Per Mike Holt's Understanding The National Electrical Code, Based on the 2002 NEC, Volume 1 on page: 88 under 220.12 Commercial - Show Window and Track Lighting Load, Mike provides calculation and explanation almost identical to my previous post.

The NEC ANNEX D Example, Mike Holt, and my Mentor Tom Henry all add the 25% if continuous load is determined, verses you and the handbook that don't. Sorry, but your arguement is not convincing. :eek:
 

steve66

Senior Member
Location
Illinois
Occupation
Engineer
Re: track light load and NEC

Sorry, but your arguement is not convincing.
I'm not trying to convince you. I'm not claiming I'm 100% sure I'm right. All I said is that I don't think you add an extra 25%. I've been hoping someone else would chime in so we could get another opinion.

Since you have found another example that supports adding the 25%, I'm starting to believe you may be right. In addition, I reread 230.42 and it does say "loads as determined in Article 220".

If you are right, it seems to raise more questions. If I add receptacle loads to lighting loads in 220.3(A) (per note b to the table), do these get another 25% also? If I use the demand table 220.11, do I add 25% and then use only xx% of the result? Is the 180VA for receptacles considered continuous?

Steve
 
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