Those "Raves in the Nave" and big Choral Concerts in the infamous Ely Cathedral have to backed by a constant and powerful, power supply. It so happens used to work in the same Building as EDL Publishing who compiled the following report about the un-celebrated, yet essential supply of Electricity around the "big house on the Hill..!"

Holy orders

The city of Ely - not only home to the fantastic people at EDL Publishing - but a small market town steeped in history too. Among many of the 'greats' of Ely is the famous cathedral. Built in 1083, the cathedral's towers dominate at every prospect. Like any building, however, the electrical infrastructure plays an important role in maximising the building to its full potential. Sarah Payne took three steps to heaven to find out more.
While Ely may be the second smallest city in England, its magnificent cathedral is a building which dominates the flat countryside of East Anglia. Known as 'the ship of the Fens' its octagonal tower can be seen from miles away.
Building of the cathedral began back in 1083 and was completed in 1351. Its original square central tower collapsed in 1322 and was replaced by the octagonal one there today. Ely also boasts the largest Lady Chapel in England. Over the years, Ely has played host to many historic heroes such as King Canute, Hereward the Wake, William the Conqueror and, perhaps more famously, Oliver Cromwell.
But behind all the fantastic architecture of the cathedral, like any building these days, it features an electrical infrastructure. Gone have the old days of gas light and dimly lit areas, to have been replaced by halogen lights and uplighters. While the cathedral is a magnificent building in its own right, the lighting plays an important part in emphasising the architecture. The combination of old and new blends together to create the perfect ambience.

A heavenly light

Being such an historic building, the cathedral naturally requires a lot of maintenance. Ian Chivers of I.M. Chivers has been responsible for the maintenance of the cathedral for the past four years. His job is to mainly check that all the lighting is in working order, as it plays such an important part in terms of both the public's safety and their enjoyment of the building. There are a combination of lights; some are there to show off the architecture, while others are essential for guidance and public safety.
All the lighting is controlled from a main dimmer unit situated in the Verger's vestry. This unit controls a number of dimming machines situated around the upper levels of the cathedral. From the unit in the vestry, a number of lighting effects have been pre-programmed. If it is a bright day or a dull day, the lighting effects can be programmed accordingly. There is an architectural setting which is used especially for events which are held at night, allowing people to soak in the atmosphere of the place and the event itself. On a typical day, the lighting inside the cathedral would not be very bright. There is no glare from the lights either. Ian said, 'It's mainly a matter of trying to emphasise focal points but without losing the overall effect. There are a number of strategically placed uplighters concentrating on emphasising the architecture. The lighting around the doors and steps is a lot more obvious, because of health and safety reasons.'
The dimming machines situated around the building feature 12 circuits, which are all controlled through a relay control circuit. The dimmers are designed to cover certain areas as it gives better local control, whereas previously there was a switch that would control one half of the building.
The lights which shine down from the higher levels all have their own separate dimmers/transformers. They all feature separate plugs which are fused inside. Ian commented, 'We do a bulb check once a month. To do this, we turn on all the lights by means of a lamp check function on the dimming unit, and then we can see which lamps have blown and need replacing. We probably replace about nine or ten a month. The upkeep of the lighting is definitely the major factor in maintaining the cathedral.'
At night, the most distinguishing and spectacular feature of the cathedral is the Octagon. This is a lantern tower which can be seen from miles around. It is lit up by a number of large halogen lights situated on the roof of the Octagon.

Testing times

Peter Wells is a director of VJ Skerry Ltd. One of his jobs is to carry out electrical inspections and tests on the cathedral. For a building as old as this, an inspection would probably be carried out every year, whereas with newer installations, it would be every three years. The company was awarded the job through a general enquiry. Peter said, 'Prior to the new electrical refurbishment, our company had been involved with the cathedral for many years. Mr V Skerry carried out a full fine-toothcomb electrical survey of the building, which enabled us to improve and maintain the existing installations. The Dean & Chapter contacted us regarding a periodic inspection and test, and to organise regular service and testing.'
Because the cathedral is such a large building, the electrical supplies extend to every part of the building. All the information as to where things are, what it should be and types of fittings etc., are all contained in what is known as the 'electrical bible'. Peter said, 'It's basically an operating and maintenance manual. If you come to do any maintenance, alterations, additional circuits etc. on the building, you would look in here, look at the circuits and change anything that is necessary and update it.'
The main distribution panel is situated in the Verger's vestry. From there, power is sub-distributed to other panels around the cathedral. To check that the system is ok, Peter carries out an earth loop test, takes the readings and records them. This proves that the external earth and the mains supply coming in is adequate to take any fault current, should it occur. Peter commented, 'If you get a good reading here, then you can expect the readings from the other panels to be similar. If there are any abnormalities or high readings, you know it's not an external problem, it's got to be internal. Then you work out the problem from there.'

Out of sight

The power runs up through the vestry ceiling, up to each floor and is distributed around. All the cabling, which is mineral insulated (MI) cable, is very neat and tidy. Peter revealed, 'Although they are quite hidden, you can see the cables if you look for them, but as long as the installation is put in neatly, the public accept it. Some of the cabling runs around the hand-carved wooden framework in the top half of the cathedral and you have to be especially careful, as the fittings are very dry and brittle as they have been there for so long.'
The emergency lighting is run off the same supply as the rest of the power. They are self-contained battery operated units. When the power fails on the lighting circuit, the emergency lights automatically come on. They are mainly designed to highlight escape routes. Peter commented, 'The emergency lighting is on a normal changeover relay, so what I do to test them is to drop out the normal supply and this should drop in all the emergency lights. Ideally, these should be checked every three months, along with the fire alarms.'
Peter goes around and does checks on all the sub-distribution panels. This involves the same test as the one on the main distribution panel; this loop test reading will include the internal and external resistance. He checks the connections to make sure there are no signs of any burning joints or overheating, and also the condition of the way things are running. If anything is not as it should be, he needs to make a report.
Once the earth loop tests have been done on each sub-distribution panel and the results prove ok, other tests are carried out to the final circuits, for example, sockets and lights including loop, earth continuity and ring continuity. The last check Peter has to do is the RCD test on the sockets. This is done by plugging the test machine into the socket and obtaining the disconnection times. Peter said, 'I have to test all the RCDs and get the time values. All these tests are carried out using one machine. All the results are stored on the machine, then I can download them to my PC.' Peter also takes digital photographs of all the distribution boards, so he can refer to them at a later stage if necessary.

Emergency signals

The power supply unit situated next to the sub-distribution panel runs equipment as part of the emergency lighting system. It features battery back-up in case there happens to be a power failure. The cathedral has a large fire alarm system. The main panel is located down in the vestry, while certain sections are monitored via infrared beam detectors. In the event of a fire, the fire alarm system will also monitor and run the sounders.
In a small compartment just outside the refectory, in a ceiling void, are all the fuseboards and sockets which feed the refectory and the cathedral shop. Peter said, 'The services are all localised within this one area which makes it a lot easier to maintain. This area can be quite tricky to get to, as the public are coming in and out of the refectory all day, so I usually have to do my tests towards the end of the day when it starts to quieten down.' The light fittings in the shop are suspended on a track, again making it easier to maintain and change bulbs.
Throughout the cathedral, the only form of heating is a number of large gas burners situated around the ground floor, which do radiate a lot of heat out. The Lady Chapel, however, is in the process of having underfloor heating installed.

A supporting role

Both Ian and Peter thoroughly enjoy their work they carry out on the cathedral. As Peter commented, 'It makes your job more interesting working on something as impressive as this building, much more interesting than a standard office installation.' While Ely Cathedral is a spectacular building in its own right, the work that goes on behind the scenes is just as important. With so much historical, architectural and ecclesiastical interest, the importance of the electrical components within the cathedral play a significant supporting role in ensuring the cathedral is portrayed to its full and maximum potential on a daily basis.


Report by Sarah Payne for Electrical Contracting News