Four work @-@ ins were held during 1984 . The first two were by apprentices from Eastern Electricity Board . Thelnetham Windmill was chosen at the project to benefit from the Young Person 's Development Project for that year . Pakenham Watermill had previously benefited from the project , and its owners , the Suffolk Preservation Trust , had suggested that Thelnetham Windmill would be a good candidate for the scheme . Two separate parties spent a week each at the mill . A mains electricity supply was provided . An underground cable was laid with assistance from British Telecom who were trialling a thrust borer which had been developed at their research facility at Martlesham Heath . The thrust borer laid 25 yards ( 23 m ) of ducting through which the mains cable was pulled into position . The mill was then supplied with lights and sockets on each floor .