I was using typical clamp on ammeter, then swicthed to my Fluke 39 power anylyzer, got the same reading. I am not really familiar with the use of the 39, so I downloaded the manual from fluke itself. One of troubles I have with the manual, it doesn't state what normal readings should be in respect to THD-R and THD-F. I am not sure if I am rading it right but the THD was showing 58%. PF was at 87. But I don't trust the readings because of my umfamiliarity with testing harmonics at this time.

The place is a fiber optic component manufatcurer and testing lab. Current electric bills are out of the normal. High side. Most of the equipment in the place are computers, o-scopes, signal generators, signal analyzers and such. Some (3) single phase 220V oven /chiller combo units.

Now their guy there tells me he thinks all the power supplies are of the linear type and not the "switching" that I am somewhat a custom too. They buy these type supplies because of potential noise problems with the "switching" type. Service incoming is 480/277v 3 phase 4 wire service with 480X208v 3 phase transformer "dry type" NOT a K-factor transformer. Most of the loads are 120v.

These measurements were taken off the subpanel on the 208/120 side.

Lighting is all 277V. T-8 fixtures

I have never seen the Nuetral current this far off before.

Any clues?


Dnk......