Hello - I'm new to this board. I had a question on track lighting. The NEC reserves a minimum of 150 VA / 2 FT for track lighting in addition to general area lighting (220.43 (B)) for feeder / service calculations. The notes section says this 150 VA / 2 FT is not meant to limit the number of feet of track on a single branch circuit. This is where it gets confusing. If I don't consider this 150 VA / 2 FT load in the individual branch circuits, how would a feeder be able to accommodate the load?
Track lighting load calc question
- Thread starter cppoly
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- Licensed Electrician
You can put as many feet of track as you want on a 20A circuit. For every two feet of it you add 150VA to your feeder calc.
hmspe
Senior Member
- Location
- Temple, TX
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- PE
Pay close attention to the wording. A requirement for a feeder calculation does not mean the requirement also applies to the branch circuit calculation. In this case if you had four heads at 65 watts on a 40' track the branch circuit load could be calculated as 4 X 65 = 260 watts, but the feeder calculation for the track would be 20 X 150 = 3000 watts.
Thanks for the reply. Here's what I don't understand though. Aren't feeder calcs based off of branch circuit calcs? For instance, a 42-pole branch circuit panel can be loaded up with all track lighting based off of the wattage of the track fixtures. Then, the total branch circuit panel VA is added up at the end and multiplied by 1.25 for a continuous load. If the feeder is sized for the panel for 150 VA / 2 FT, but what good is it if there's no capacity in the branch circuits to accommodate this?
As a note...........this is not residential ................................residentially speaking, you could put 100 yards of track on a circuit if you would like (not recommended).
- Location
- Chapel Hill, NC
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- Retired Electrical Contractor
A feeder generally has many different circuits and one would not expect all of those circuits to be running at 100%. If the panel had all track light circuits then you could base the load calculation on the linear footage of the track. If per chance you know that the wattage of the # of fixtures will be far greater than the calculated load then one would be expected to base the load on those numbers. The branch circuit is 20 amps. If you go over the 20 amp max on the circuit you will trip the breaker however the feeder should still be okay if the calculation was done based on the number of fixtures and their actual wattage. The branch circuits will limit the feeder. If all the circuits are loaded to the max then the feeder better be able to deal with it.
yum yum eatum up
Dennis what do you mean by this? If I include the length of track into the branch circuit calculation then wouldn't this limit the length of track on a branch circuit?
Not Dennis but.........the length of your track is dictating the size of the circuit.........too long??? too many va's..... time for another circuit........to many circuits and va's...time for a larger feed.
"If I include the length of track into the branch circuit calculation then wouldn't this limit the length of track on a branch circuit"?
yep..............it should..... 150va per 2'. ..............it be what it be.
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- Licensed Electrician
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The length of the track is irrelevant concerning branch circuits. Put as many feet as you want. There is no limit to the length of track you can put on one branch circuit.
When you do a load calc you figure your VA per two feet of track. If you had one panel just for track lighting it could have one breaker in it, the feeder calc would be the same.
The length of the track is irrelevant concerning branch circuits. Put as many feet as you want. There is no limit to the length of track you can put on one branch circuit.
When you do a load calc you figure your VA per two feet of track. If you had one panel just for track lighting it could have one breaker in it, the feeder calc would be the same.
- Location
- Chapel Hill, NC
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- Retired Electrical Contractor
I agree . The calculation is for feeders or service not branch circuits. Art. 220.43(B) is under section III which is feeder and service load calculations.
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- Licensed Electrician
Thanks Dennis. I was not trying to answer for you, but you had not jumped in.
- Location
- Chapel Hill, NC
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- Retired Electrical Contractor
I appreciate you taking over- been busy here lately. :thumbsup:
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