How Each Interrupts Current
An oil circuit breaker (OCB) interrupts current with the contacts separating in insulating oil, which cools and extinguishes the arc. A vacuum circuit breaker extinguishes the arc inside a sealed vacuum interrupter with no oil or gas involved. Read the basics in what is a VCB.
Maintenance Comparison
- OCB - the oil degrades with repeated operation and must be tested, filtered, or replaced, and contacts need periodic inspection.
- VCB - the interrupter is sealed, so contact maintenance is largely eliminated, and routine work focuses on the mechanism and control components.
Safety Considerations
Oil is flammable, so an OCB carries a fire risk that a vacuum breaker does not. Oil breakers also require care with oil handling and disposal.
Size and Operating Life
Vacuum breakers are generally more compact and are well suited to frequent switching duty. That is a major reason vacuum technology has largely replaced oil breakers in new medium-voltage installations.
If You Still Run OCBs
Plan spares carefully, since oil breaker parts are increasingly hard to source, and consider a retrofit assessment. See retrofit vs replace.
Browse vacuum breaker spares or request a quote.