general lighting load demand factor in nec

[coke03p]

I am looking for some help in regards to the general lighting load tables in the NEC. I am a Prime Power Specialist in the Army, so I do not really use too much of the NEC. I deal with higher voltage installations and aspects of medium voltage power generation. I am currently enrolled in a NEC class and we are going over service calculations. Part of the service calculation is the general lighting load. The chart clearly says for the type of structure what the demand is per square foot. Then once you have figured that out you go to the demand factor chart to determine your multiplier. My question is if you have a restaurant, which will be a continuous load, does the NEC already take that into accout when you use the 2VAs per square foot, and you go to the demand factor chart and it tells you it is at 100% or do you have to then multiply by 125%. The NEC does not say you have to multiply general lighting by 125% if its going to be a continous load like a restaurant would be however we are being told we should. I am looking for some help on clearing this subject up. thanks

 

[charlie b]

Re: general lighting load demand factor in nec

I always multiply the lighting load by 125%. There is no easy way to justify a claim that the lights would not be on for more than 3 hours at a time, regardless of what type of facility you are designing.

 

[bphgravity]

Re: general lighting load demand factor in nec

You required by the NEC to increase any of the general lighting by 25%. An example of this and an explanation is provided in the NEC at Example D3 Store Building.

 

[coke03p]

Re: general lighting load demand factor in nec

thanks for the info guys, its very useful. It will add to the class I am sure.