Power factor correction

[mego6000]

Hi everybody
I'm wondering about the effect of capacitor bank used for centeral power factor correction on the mainboard circuit breaker rating? I already know how to select the cable size and the circuit breaker of the capacitor bank but I didn't find any thing in the code about the effect of this PFC on the mainboard circuit breaker could anyone help me in that please,
many thanks,

 

[bphgravity]

Re: Power factor correction

I don't understand what you mean by "effects on the mainboard circuit breaker rating?" Please explain.

Central power factor correction is used to reduce the reactive power on a distribution system that supplies highly inductive loads.

 

[Ed MacLaren]

Re: Power factor correction

I didn't find any thing in the code about the effect of this PFC on the mainboard circuit breaker

I don't think you will.

Most codes do not permit a reduction in (service, feeder, or branch circuit) wire size or overcurrent device rating, because, if the capacitors fail, the load current will go back up to the value that it would have been without the PF correction.

Ed

[ May 21, 2004, 11:36 AM: Message edited by: Ed MacLaren ]

 

[mego6000]

Re: Power factor correction

Thanks Ed and Brayn For your replies and to Brayn I like to explaine my point again. This time, I'll use simple example: If I already have a mineboard of (XX) Amp main circuit breaker and feeding (X) branch circuits and the power factor of the total load is around 0.75. Now if I want to add centeral power factor correction do I need to change the main circuit breaker of the board or not? and why?

many thanks,
Amged

 

[steve66]

Re: Power factor correction

No, you do not have to change the main breaker. The PF correction will reduce the current through the main breaker, so now the main breaker will be a little larger than it needs to be. But that's OK, main breakers are usually sized larger than necessary for all the branch circuits fed to allow for future expansion. And each branch circuit is still protected by a branch breaker.

Steve