NEC & IECC Lighting Load Calculation

[tejpathak]

I am an Electrical Engineer and I am confused about the feeder and service calculations for lighting load as per NEC Vs. IECC.
The general lighting load as per NEC Table 220.3(A) is way more than ?International Energy Conservation Code? (IECC) Table 805.5.2.

For example as per NEC the VA/SF for Banks is 3.5 compared to 1.5 W/SF as per IECC.

NEC Handbook states this table as minimum lighting load with no exceptions but if I follow IECC it does not make any sense to oversize the feeders and service as lighting load is going to be lesser.

Does anyone else agree with this discrepancy or am I missing something?

By the way, I would like to thank all the members of this forum. I try to visit this forum atleast once a week as there is always bunch of information and on top of that people who want to share their knowledge which is not common.

 

[cpal]

Not being familiar with applying IECC is it giving illumination levels???
Per 220.12 Table (0ld 220.3)

The general lighting load usually includes illumination and convenience outlets.

 

[jtester]

You must size circuits according to the NEC, but you're allowed to install only the wattage permitted by the IECC. I agree the NEC is way overkill, but it will change when everybody follows the IECC or something similar.

Jim T

 

[charlie b]

In Washington State, there is a local rule that allows us to use the values of watts per square foot given in the energy code, instead of the values in the NEC. This gives us a lower calculated load, and keeps the electrical code and the energy code from imposing conflicting requirements. There may or may not be a similar local code in your area.