Nec exam prep

[spurlob6968]

In the nec exam prep book there is a load calc example for a bank's general lighting and recepticle load. When calculating the lighting load it is using a 125% factor to finish the lighting calc. Where does this come from? It does not specify that it is a feeder it just ask for the Load. I do not see anything in the NEC for this factor. Could you please help.

 

[augie47]

Welcome !

This was discussed earlier here:

http://forums.mikeholt.com/showthread.php?t=120845&highlight=%22continuous+load%22

as noted, it is not addressed directly in the NEC as to which lighting loads are "continuous" but pretty well depends on "practical" input.
Most commercial businesses lighting loads would be continuous.

 

[spurlob6968]

But if you are just calculating load you would not need to do this correct. The 125% referenced is for overcurrent protection and also there is one for wire size but not for calculating just the load right?

 

[BAHTAH]

bank's general lighting

bank's general lighting

But if you are just calculating load you would not need to do this correct. The 125% referenced is for over current protection and also there is one for wire size but not for calculating just the load right?

In a commercial application such as a bank you would need to calculate the lighting load at 125% because it will be in operation for 3 hours or more. It is the operating time that determines if the lighting load is considered continuous. That load will be calculated at the branch circuit as well as the building service. The lighting load for fixtures in a closet at the bank would not need to be considered continuous since the load would most likely not operate for 3 hours or more, but the general lighting would.