Salt-fog testing of composite insulators

The results of salt-fog tests performed on silicone rubber insulators have been complemented by measurements of water droplet contact angle. The performance of these insulators was mostly inconsistent with service experience and this was attributed to the continuous nature of the test which inhibits the processes of rejuvenation for which silicone elastomers have become renowned. The validity of the salt-fog test in qualifying silicone insulators is questioned and proposals are made for alternative procedures