Our staff, some with over 25 years experience, have the ability to design switchboards to replace old equipment, taking into account the existing installation.

The LV switchboard in this instance was supplied to the head office in London of a major high street retailer and our brief was to remove the old equipment, design, manufacture and install the new panel taking into account the restrictive conditions of the switch room and the position of the existing incoming and outgoing cables.

The mains and generator incoming cables were both approximately 50 years old; paper lead sheathed and rated 1600A. They entered the switch room in ducts under the floor at right angles to the front of the panel, entering at the bottom. No movement could be gained on these cables and no adjustment to the bolted lug connections was possible therefore our new termination point needed to be precisely positioned to line up with the existing.

The outgoing cables, again approximately 50 years old, were single core braided and twisted 'pyrotenax' and approximately 240 sq mm in todays equivalent. Again no adjustment or movement was possible and to accommodate this, the new switchboard needed a special terminal chamber in exactly the right place with the ability to 'fine tune' the position of each terminal to precisely line up with the individual cable.

The client required an increase of 50% more outgoing ways plus the addition of power factor correction, with no increase in the overall length, height or depth of the existing switchboard. These restrictions were compounded by the site conditions. Access to the switch room was gained through a hole in the road, lowered down two floors and manoeuvred through two standard personnel doors and down a corridor. All this on a floor level with steps of approximately 300 mm at each door.

Finally the client could only allow the supply to be off for 36 hours.
Our engineers visited the site and after several surveys, many in the early hours, and our final design and method statement was put to the client.

The switchboard was to be manufactured to precisely replace the existing equipment since no movement could be made to the existing 'pyro' cables for fear of them breaking down. It was therefore necessary to manufacture special brackets to support the existing gland plates, thus supporting and protecting the cables.

The old switchgear was then dismantled leaving the old gland plates suspended in place and the new panel was then assembled beneath.
The work crew was divided into two 4 man teams working 12 hour shifts, and although we encountered a few 'surprises' along the way, our in-depth preparation meant that we could deal with them efficiently as they occurred and we managed to complete the changeover in 24 hours leaving our customer 12 hours spare to re-set his equipment.