By Mark Summerton, NAPIT-registered electrician · 28 October 2026
The job in brief: a new three-phase mains supply, a new distribution board and a dedicated mechanical board to power five new air conditioning units at a school in Ascot. It was completed by a two-person team in 3 days, during the school holidays.
A school in Ascot was installing five new air conditioning units. The existing electrical setup wasn’t built to take that extra load, so they needed a proper supply and distribution system to run the units safely and reliably for years to come.
What the School Needed
Enough capacity for five AC units. Air conditioning is a heavy, constant load, and five units needed a supply sized for it.
A separate, easy-to-isolate system. The air conditioning engineers needed to be able to work on the units without affecting the rest of the school.
No disruption to teaching. The work had to be finished before pupils came back.
What We Installed
A new three-phase mains supply, sized for the AC load with room to spare
A new distribution board with an isolator and surge protection
A dedicated mechanical board feeding all five air conditioning units
New cable tray and trunking, keeping the cabling fully contained and neat, with steel containment for the main supply cables
Everything was tested and certified on completion.
Why a Dedicated Board for the Air Conditioning?
Putting the air conditioning on its own board has three practical benefits:
Faults stay contained. If an AC unit develops a fault, it trips on its own board, and the rest of the school keeps its power.
Maintenance is simpler and safer. The AC engineers can isolate their equipment in one place, without touching the school’s lighting and power.
There’s room to grow. The board has spare capacity, so more units can be added later without starting again.
Working Around a School
Schools can’t simply shut down for a few days, so timing was everything. We booked the job for the school holidays. A two-person team completed the whole installation in 3 days, and the school was fully powered and certified before term started. That’s the same approach we take for offices, shops and business units: we plan the work around your opening hours, not the other way round.
Commercial Electrical Work in Surrey and West Sussex
This job was a little further afield than usual. We normally cover Horley, Crawley, Reigate and Redhill, including business parks like Manor Royal. Distribution board upgrades start from £1,500 + VAT, subject to survey, and we give you a fixed written quote before any work starts.
See our commercial electrical services or call 07508 224603.
Frequently Asked Questions
Can you install a three-phase supply for a business or school?
Yes. We install and upgrade three-phase supplies and distribution boards for schools, offices, shops and industrial units, including the testing and certification on completion.
Can the work be done without shutting the building?
Usually, yes. We plan the work around your opening hours: out of hours, at weekends or during holidays. Power is only off for short, planned periods.
How much does a distribution board upgrade cost?
Commercial distribution board upgrades start from £1,500 + VAT, subject to a survey. The final price depends on the size of the board, the supply and the number of circuits.
Why put air conditioning on a separate board?
It keeps faults contained, makes maintenance simpler and safer for the air conditioning engineers, and leaves spare capacity for adding more units later.
