Lubrication of circuit breakers - HSE Website
Investigation into an explosion of a HV circuit breaker indicated that recently carried out maintenance may have been a causal factor. The incident resulted in catastrophic failure of the HV circuit breaker leading to fire / explosion and could have resulted in fatal injuries. Maintenance of HV and LV circuit breakers typically involves both the cleaning and lubricating of the operating mechanism. The HSE investigation found that the same physical product was used for both maintenance activities, but evidence shows the product was in fact only suitable for cleaning and NOT lubrication. This situation may have arisen because of the availability of different products, (for different purposes), within the same product range, or changes to the products composition over time whilst retaining the original name. It is essential that the correct product is used for each task.