Load Diversity adjustment factors

[bartb102]

Anybody know the definition of LOAD DIVERSITY for adjusting the ampacity of conductors in a raceway? Table B.310.11 allows increasing the ampacity of conductors in a raceway, but I can't find a basis for determining what is 50% load diversity.

I need 18- 10ga. conductors to feed a batch of 1KW lights. Using table 310.11, I can only put 9 conductors in a raceway, or the ampacity is reduced from 70% to 50%. Table B.310.11 allows 70% multiplier for 10-24 conductors if load diversity is allowed.

As these are known fixed continuous loads, and all but ground wires will be handling the load, I believe I have to use the 9 conductor limit, just looking for confirmation.

bartb102

 

[dpc]

Lighting is generally always taken as a continuous load. So you can't take any credit for diversity.

 

[tommom]

You could use diversity if you had some means of assuring that not all of the lights would be on at the same time, for example, or if you're dimming them and they can not all be on full brightness at the same time(between circuits of course.)

An analogous situation would be where you have electric heating and electric cooling, and you know they're not both going to be on at the same time.

Lighting usually doesn't work that way.

 

[stevenal]

From IEEE 100;

"The difference between the sum of the maxima
of two or more individual loads and the coincident of combined maximum load usually measured over a specified period."

Since you state the loads are fixed and continuous, you have no diversity.