Causes of Circuit Breaker Flashover

Flash over occur may be due to-

1. Invation of rats or other foreign materials in breaker cubicle.

2. Vapour accumulation(if heaters were off).

3. loss of vacuum property.

4. dust accumulation on breaker poles.

Thank you.

However can we do why why analysis to reach to the root cause.

for example :

1) Flash over means sparking or extra heating

2) Why sparking and extra heating

3 ) due to invation of foreign particle ( how we can link flash over and particle invation)

Suppose, a rat has entered into the brk cubicle. It may jump from one breaker pole another or may cause one poll to earth conduction. this ionised the whole surrounding and then flashover among the poles has occured.

Now, rat may enter the brk. cubicle through a hole. This hole may be due to design failure or for control cable entry etc. So block the hole by using m-seal etc.