Why Spares Planning Matters
The cost of a switchgear component failure is rarely the cost of the part itself; it is the cost of the outage while you wait for it. Standard components may be available quickly, but specific mechanism parts, coils, or motors for a particular breaker model can have long lead times, particularly for older or less common equipment. A critical spares list identifies which parts are worth holding in stock precisely because their absence would prolong an outage far more than their cost justifies.
How to Decide What Counts as Critical
- Consequence of failure — how much does an outage on this feeder or breaker actually cost the operation, in lost production or supply?
- Likelihood of failure — parts that wear or fail more frequently by nature (coils, auxiliary switches, spring charging motors, contacts) deserve higher priority.
- Lead time — parts that cannot be sourced quickly are stronger candidates for holding stock than parts available off the shelf.
- Fleet commonality — if the same part fits several breakers on site, one spare covers more risk.
Commonly Stocked Categories
For vacuum circuit breakers, operators commonly consider holding trip and closing coils, spring charging motors, auxiliary switches, and relevant contacts or mechanism components for their specific breaker models, since these are the parts most involved in operational faults. Vacuum interrupters themselves are typically replaced on condition or at end of life rather than kept in large quantities.
Practical Tips
- Record exact breaker model, rating, and nameplate details so spares can be matched correctly.
- Store spares properly — protected from moisture, dust, and physical damage — and check them periodically.
- Review the list after any repeated failure or equipment change.
Need help building a spares list for your breaker fleet? Send your equipment details or browse VCB spares directly.