In January 2007, we completed a job for the National Grid at Tottenham. The substation supplies power to much of the North of London, it has been in service since 1960 and some of the high voltage insulators were starting to breakdown internally.
So a very urgent replacement programme was put in place to renew the equipment.

Lloyds British were contacted with a view to fabricating a spreader to lift out the so called 'through floor bushings', raise them 7m out of the housings, run each one around 20M along a temporarily installed runway, then lower them 30m to the floor. Each of these bushings weigh 3000kgs, and connects high voltage wiring from one floor to another within the substation. These bushings carry 275,000 volts and 750,000 amps and have refrigerant gases circulating within to keep them cool when fully operational.

Working closely with National Grid engineers, a plan was drawn up, as the outage of the power station had to be kept to an absolute minimum. Each engineer was put through an induction and training programme, as in certain areas of the station which were still live, raising your hand above your head could result in it being blown off by a high voltage strike!

Once the plan was hatched it was all put in motion very quickly. Around 80m of runway beam was fitted, along with the 3000kg electric chain hoist and wiring. Test weights were taken in to proof load test the complete assembly.

It was then handed over to the National Grid for use. Lloyds British were asked to be in attendance for the duration of the job in case of any hoist breakdowns, and they also requested a 24 hour emergency callout number for nights. But the job all went very well, with only a few minor hitches, and the substation is now back on line serving London.