Connect Saint Helena Ltd would like to apologise to those customers on Feeder 2 who were without power on the morning of 7 December 2015 and again in the early hours of the 8 December.
The outage lasted for several hours and for much of that time we were unable to give any explanation for the cause of the fault or how long it may take to repair. We are now able to explain to our customers the reason for the delay in restoring power.
Our switching back procedures enabled us to narrow down the fault location to somewhere in the area between Milking Pound and Grapevine Gut. In this area the network is a distance from the road and runs across uneven fields. Our experienced linesmen and specialist contractor walked the length of the lines, constantly looking upwards for anything unusual that might be causing the problem. Eventually a slightly damaged ceramic pin insulator was spotted and the power turned off for a short period to allow the insulator to be quickly and safely replaced with a new silicone version.
Ceramic insulators can last for many years and sometimes they can fail for no apparent reason. In this case there was a very small hole in the surface glaze which, over time, has allowed moisture to seep in. The moisture eventually caused an intermittent shorting inside the insulator which in turn tripped the feeder 2 switch. There is no obvious reason for the damage so the insulator could have been in this condition for a long time but it would be impossible to see from the ground during a routine inspection.
Silicone insulators have been used on all new installations and repairs for a while now as they are known to be robust and long-lasting. There are still thousands of older ceramic insulators and the majority are in good condition so to replace them all will take a long.
A photograph in the newspaper would not show the damaged insulator with sufficient clarity but if anyone is interested, they can view the insulator at our Seales Corner office!