Lighting panel load 1

[surineman]

I have 135 kVA lighting transformers in one industrial plant.

I am wondering how much of it should be considered as connected load? or continuous load? is there any rule of thumb?

I am filling new costumer connection load form for supply request and i need to know how much of it should be considered? all of it? or i should count my total loads (lighting, receptacles, ...)

Thanks

 

[mpparent]

Can you take some spot readings, or better yet, put a Dranetz on them to get a baseline reading??

Mike

 

[alehman]

For the purposes of the U.S. National Electrical Load, any load expected to operate for more than 4 hours at a time is considered continuous. In most buildings, lighting load would be considered as continuous.

Receptacles calculated at 180VA each as required by the NEC are also considered continous (diversity factors are allowed for large receptacle loads).

 

[surineman]

alehman,

4 hours at a time, means 4 hours per day or anytime or ...?

Thanks for responses

 

[davidbeach]

The NEC definition, from Article 100 is

Continuous Load. A load where the maximum current is expected to continue for 3 hours or more.

That would be 3 hours continuously; even 3 hours continuously only once per month (or even once per life time) would be a continuous load. This is a thermal rating, where the protective device will overheat if not rated for 100% continuous load (the default is 80% of nominal rating for continuous loads). Certain devices are rated for 100% continuous loads and do not require derating; these are devices capable of dissipating the heat of 100% loading without damage to the device.