The contact resistance of VCB is typically very low.

• VCB stands for Vacuum Circuit Breaker.

• The contact resistance is the resistance between the contacts of the breaker when it is closed.

• The contact res...read more

As a general rule thumb

100 u ohm or less, it is more than 300 u ohm than there is issue

As per standards ideal is less than 100 micro ohms and anything more than 250 micro ohms is of concern and must be attended.

We measured contact resistance of VCB (11KV), the values are as below:

Phase Applied Current Resistance
L1 100 A 17 μΩ
L2 100 A 32 μΩ
L3 100 A 23 μΩ

Low voltage circute breaker

Vacuum Circuit breaker Working

Vacuum Circuit breaker Working 

Vacuum Circuit breaker Working

Value of resistance