Determining power factor to use for load calculation from utility bills

[iwire]

Besides PF, note that there is no requirement to consider lack of perfect balancing, nor whether the load is continuous or not. Personally, I find only 25% adder beyond the demand figure to be cutting it kinda close compared to "regular" NEC load calcs.

Most utility bills will have a VAR field which could be used to get average PF, but of course that wouldnt give you the PF at the period of max demand.

Is it cutting it close when the new load being added will be calculated per 220

 

[electrofelon]

Is it cutting it close when the new load being added will be calculated per 220

Good point, that certainly buys one more room. The last few times I used 220.87 there was no added load; it was just to replace old existing equipment with issues, or to add a generator.

 

[NewtonLaw]

I am looking at a years worth of utility bills trying to come up with an existing load for a load calculation based on NEC 220.87. The monthly bills provide an "On-Peack Actual Demand" value in kW which appears to represent the maximum kW demand for the given billing cycle (month)

Obviously in order to convert this to a maximum kVA value and ultimately an maximum load amperage a power factor has to be known. In previous bills I've reviewed a minimum power factor for each period was provided which I typically used to convert the max kW to a kVA value.

With the absence of a power factor value is there a typical "minimum" value that is assumed/used when trying to determine max kVA/Amps from utility bills? The facility is likely classified as an industrial facility with several motors, machinery, etc... so I'm not sure if there are different power factors used for this case depending on facility type?

I am not sure this will help because each Industrial plant has it own PF, however, if the Industrial complex is in PPL EU territory in Pennsylvania, they can supply you with the actual 15 minute demands for both the kW and kVAR loading for up to 5 years of history. With todays meters, many Utilities can provide this information. Failing that my experience has been that if your customer is paying for VAR loading, usually the PF runs near to 85%. If the customer does not directly pay for VAR loading, 90% of the customers in my area run between 70 and 75%. This comes from 40 years of experience checking loading levels of primary feeders which require knowledge of all attached customer loads.

Hope this helps,

NewtonLaw