Circuit breaker rate sizing

[Mark_Djorn]

Hi all

I would like to know what should be the rating of Air Circuit Breaker to select for a Genset based on the following data:

2000k VA
PF 0.8
1600k W load connected to the Genset via dedicated busduct.
Supply: 415 V

I have an idean in mind (whether right or wrong) but I would like you to advise me please.
Thank you in advance

 

[plugsandsparks]

MasterPacT MTZ Circuit Breakers - UL/ANSI | Schneider Electric USA

Schneider Electric USA. Browse our products and documents for MasterPacT MTZ Circuit Breakers - UL/ANSI - LV power circuit breakers from 800 A to 6000 A

www.se.com

As used by DNO, lol - suggest go around 3000-4000A rating and adjust settings to suit, good luck

 

[Mark_Djorn]

MasterPacT MTZ Circuit Breakers - UL/ANSI | Schneider Electric USA

Schneider Electric USA. Browse our products and documents for MasterPacT MTZ Circuit Breakers - UL/ANSI - LV power circuit breakers from 800 A to 6000 A

www.se.com

As used by DNO, lol - suggest go around 3000-4000A rating and adjust settings to suit, good luck

Thank you for your speedy reply.
Being my company the one paying for the equipment, I wonder if I can optimise costs by purchasing a 2500A breaker.
Here is my calculations to see if you find them right:

1600kw
415V
Resistive load, 3 phase balanced.
This means I = 2,226A
Assuming I consider the Genset to cater an extra 10%, that would be I = 2,450A despite the Genset is not meant to work at 110% load.

I feel wasting money if I had to buy a 3200A breaker and having anyway to calibrate trip settings at 0.78 (or 2500A).
Am I right to say that (conversely to cable size meant to be sized in excess), a breaker should be sized to protect my Genset?
Thank you again

 

[plugsandsparks]

Dont forget Power Factor which may be significant

 

[plugsandsparks]

Dont forget Power Factor which may be significant

Oops forgot you said resistive load....

 

[DPG]

Oops forgot you said resistive load....

I think he says PF is 0.8

 

[plugsandsparks]

Oops forgot you said resistive load....

Depends on Gen Set, where are you going to put the breaker. Gen sets often come with load side protection.

 

[plugsandsparks]

I think he says PF is 0.8

Yep post one its 0.8 , next post its 1.... who knows?

 

[DPG]

Yep post one its 0.8 , next post its 1.... who knows?

Oh yes good point.

A

 

[Mark_Djorn]

Dont forget Power Factor which may be significant

For resistive load is 1

 

[Mark_Djorn]

Yep post one its 0.8 , next post its 1.... who knows?

0.8 is the Genset PF (alternator).
1 is the load PF.
For calculations you use 1600kW with PF 1 because resistive.