Continuous general lighting for commercial?

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madayew

Member
Location
NC
Occupation
Electrician
Hello,

I have missed a practice test question where it was for a 60x80 store or 4800 square feet which equals 14400 VA once multiplied by 3

My question is where in the code book does it mention this number must be adjusted 125% because it is a continuous load or 18,000 VA?

I understand store lights would operate for more than three hours but where does it say it in the code? If all commercial is assumed to be continuous then what about Churches that would have intermittent lighting?

Thanks!
 

charlie b

Moderator
Staff member
Location
Lockport, IL
Occupation
Retired Electrical Engineer
You are likely to get contradictory answers to this question. My opinion is that when you pull the 3VA/SF value out of the table, that value already takes into account the continuous nature of lighting systems. So you don't take the 14400 VA and multiply by 125%. That value, by the way, refers to the amount of allowance we must include in the service load calculation (i.e., to size the service equipment). We are allowed to install less lighting load than that, and often do when we use LEDs. On the other hand, if you add up the actual lighting load (i.e., how many fixtures of what types and of what wattages are planned to be installed), and show that load on a panel schedule, you are no longer dealing with allowances, and must apply the 125% factor to this load.

A more important, and unknowable, detail is what the author of the test question had in mind.
 

Eddie702

Licensed Electrician
Location
Western Massachusetts
Occupation
Electrician
All commercial load is not continuous.

The calculation would be (for the entire building) the non continuous load + (continuous load x 125%)=total
 
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