Derating

[Sparkynicm]

Friday (10-15-2010) a co-worker and I were laying out a project, and he is currently studing to take a colo. journeymans (so he knows it all!!!!) anyway NEC 310-15 where it talks about derating there is a FPN or an exception, and it says (and I dont have code book right in front of me, so it may not be word for word...) that if "there is load diversity" you can use the chart referenced in annex. whatever. WHat is this load diversity? The only thing I can think of is, i.e. two motors that will NEVER be runing simultanously, oor something to that effect. It surely CANNOT mean lighting and power as load diversity in the same conduit. Can someone enlighen us? WHAT IS CONSIDERED "LOAD DIVERSITY"?

 

[Smart $]

Friday (10-15-2010) a co-worker and I were laying out a project, and he is currently studing to take a colo. journeymans (so he knows it all!!!!) anyway NEC 310-15 where it talks about derating there is a FPN or an exception, and it says (and I dont have code book right in front of me, so it may not be word for word...) that if "there is load diversity" you can use the chart referenced in annex. whatever. WHat is this load diversity? The only thing I can think of is, i.e. two motors that will NEVER be runing simultanously, oor something to that effect. It surely CANNOT mean lighting and power as load diversity in the same conduit. Can someone enlighen us? WHAT IS CONSIDERED "LOAD DIVERSITY"?

Load diversity, in short and as used in the NEC, is where the maximum number of CCC's at any point in time is less than the total CCC's in a conduit.

The following is a composition image of where the term diversity is used in the NEC... except 400.5(B) which has the same FPN as Table 310.15(B)(2)(a).