Do Breakers trip on irms(total)

[treezleef]

Hi,
Say i have a 16A load on a Mains 16A circuit at 230VAC.
If its not power factor corrected, then is there a danger the breaker could trip? (due to the reactive current being high aswell).

 

[pc1966]

Short answer = Yes

Breakers and fuses look at Irms and will trip on sufficient overload. However, most reactive loads have a significant inrush current as well so the rating of over current protection has usually to have a certain factor above the current you might compute from P/V (even allowing for typical PF)

 

[Lucien Nunes]

MCBs respond to current. A 16A load is a 16A load, it doesn't matter what the power factor is. That only shows how much real power you get from the 16A and the MCB doesn't know or care about power.

Re. RMS, the overload (thermal) element of the MCB responds to RMS current because it operates on the heating power of the current in a resistive element. But the instantaneous trip (magnetic) element responds more closely to the mean current because it operates on the force exerted by a solenoid, in which the power dissipation is unimportant.