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# Volts x Amps x Power Factor = what?

Member Posts: 2,144
If the power we are getting at the  comp terminal block is considered "powerfactored " already , then do we have to figure in the "power factor" again when we do the V x A x PF = watts thing?

• Member Posts: 7,356

Not quite sure what that means, but more importantly what are you trying to calculate?  Conductor size?  OCPD size?
• Member Posts: 2,144
V x A x PF

Thanks SWEI, This "thinking process" was thought up when installing a Circuit Breaker on the 24v side of a 208/240v by 24v transformer. We the consumer are paying for the electricity for our CentralAC, isn't that power at our house different than the power at the power station? And we pay for the power at the power station, not the slightly less power that we receive at home ? Is that correct? That's what I mean by PF'ed already! If I make sense! LOL
• Member Posts: 503
acdc

Yep Techman, good question.

When sizing fuses for DC, its VxA=W.

For AC its VxAxPF=W.

If we are looking for the fuse/breaker size for an appliance, you can use standard 125v or any numerical value you deem proper and place the appliance watts in the equasion VxAxPF=W if you are unsure what the actual voltage is.

What Techman is asking is, if you test your wall outlet and get 119vac, why do you still use the power factor in the equation? That is like taking the "efficiency" factor and using it twice.
:NYplumber:
• Member Posts: 2,144
VxAxPF

Yeah, KindaSorta like NYp said, I think
• Member Posts: 7,356

reads true wattage, and properly accounts for power factor.

The separate demand load (kVA) and reactive load (kVAR) charges on a commercial account cover the utility's butt if you are doing bad things to the grid.
• Member Posts: 15,170
edited June 2014
VA vs Watts

I'm a bit confused by this thread.

The reason VA is different from watts is because some loads, such as an inductive motor will cause the current draw to be out of phase with the voltage.

In most places, you pay for wattage not VA so a poor power factor won't cost you a dime, you're still paying for real power, not apparent power.

When sizing a breaker, fuse or conductor I would think you go by current consumption alone, not volt-amps or watts?

I'm posting because I want to make sure my understanding is correct. If it is not, please let me know.
Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
• Member Posts: 7,356
Correct on all counts

Power companies meter kVA and kVAR on medium to large commercial and industrial accounts.