load calculations and circuit

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mannyb

Senior Member
Location
Florida
Occupation
Electrician
If i have 150' of track light to put on load calculation do i just use the linear footage of track 150' x 150VA x 1.25 / 2 = 14063VA for calculation


If I wanted to power the track lights and my available power is 20a 277v circuit. I would need 14063 / 5540 = 2.5 or 3 circuits??

does this look correct? or is there something else that would determine how many circuits I would need or not need?
 

xformer

Senior Member
Location
Dallas, Tx
Occupation
Master Electrician
If i have 150' of track light to put on load calculation do i just use the linear footage of track 150' x 150VA x 1.25 / 2 = 14063VA for calculation


If I wanted to power the track lights and my available power is 20a 277v circuit. I would need 14063 / 5540 = 2.5 or 3 circuits??

does this look correct? or is there something else that would determine how many circuits I would need or not need?

IMHO,
150' track light = 150/2 = 75

75 x 150VA x 125%= 14063 VA service load


Branch Circuit Load depends on layout, actual number of fixtures on the track, and manufacturer specifications.
 

victor.cherkashi

Senior Member
Location
NYC, NY
see 220.43(B). I believe you don't have to calculate the branch circuit based on 150VA. you should use 150 VA for feeder total load size that effects your panel size.

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victor.cherkashi

Senior Member
Location
NYC, NY
Then how would you calculate the track circuit(s) ?
I just summarize wattage of all fixtures on the track. Or I go by maximum wattage permitted by energy code for the area where track is installed. For most of occupancies it should be less than 1w/sq.ft.

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ritelec

Senior Member
Location
Jersey
I just summarize wattage of all fixtures on the track. Or I go by maximum wattage permitted by energy code for the area where track is installed. For most of occupancies it should be less than 1w/sq.ft.

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Yes. I see 410.151(B) you can load the track to 100% of the track rating and apparently the branch circuit having a rating not more than that of the track. So.... It sounds like you can make that track as long as you want to make it and load it to its max amperage @ 100%. I don't see it referring back to continuous duty @ 80%. Is it assumed that the load is should be rated to 80% commercially and that's why there's no limitation residentially?
 
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