Primary Injection Testing

[ahoffart]

I'm looking for information on primary injection testing for breakers on our 480V switchgear. I've been told that 300% of rated current is used for testing and 10x is used to test instantaneous trip functions. Is there information that describes the recommended values and are there standards that govern the use of this testing on circuit breakers? Any help is appreciated.

 

[Zogzog]

LT is typically tested at 3x
GF and ST at 1.5X
INST is a just a pickup.

ANSI/NETA standards provide guidelines for primary injection testing.

The manufacturer provides time current curves for determining what values are acceptable.

 

[wcarter]

ahoffart,

Zogzog is correct. I work for a breaker manufacturer and previously for a NETA test company. You will also need to check into disabling the ground fault function, if applicable, and ZSI (Zone Selective Interlock) if on older breakers. This is normally accomplished by a jumper, or by a secondary test set.

Also, the manufacturers will many times give a testing guideline on how their breaker should be tested. Though many times, this will follow NETA/ANSI recommendations.