Dual-supply marshalling box saves equipment and time for hospital project
Hager’s Klick.system dual-supply marshalling box has achieved savings in equipment and time for the installation of essential and non-essential lighting circuits in the new 2000 m2 outpatients’ clinic at Winchester Hospital. These marshalling boxes enable both essential and non-essential lighting circuits to be fed from the same marshalling box and also be controlled by a single digital sensor and wall switch, instead of doubling up on equipment.
These installed sensors have presence detection and also daylight linking in areas where there is some natural light. They have just occupancy control in areas where there is no daylight, such as corridors. All circuits are wired for semi-automatic control, so a wall switch can over-ride them where needed.
Derek Hardy, electrical engineer for estates design and technical services at the NHS, explains, ‘Providing two lighting circuits in all of the rooms and corridors reduces the load on the essential supply if there is a mains outage. This allows the emergency-generator infrastructure to be used for more essential services — such as operating theatres.
‘Achieving this configuration without a dual-supply marshalling box would prove far harder. A conventionally wired system would involve two light switches and/or two sensors — one for each lighting circuit. Even if marshalling boxes were used, you would still need to double up, which involves extra expense and time.’
If either supply is lost, the dual-supply marshalling box will ensure luminaires on the essential supply side will remain on. Occupancy sensors and other control are connected to the essential side of the unit.