WELU Series Safe Supply Unit

WELU series of composite Safe Supply Unit comprising of a 1:1 ratio, double wound transformer with a centre-tapped restricted earth output and extra high sensitivity RCD protection.

Enclosure
Wall mounting, sheet steel with a durable, white, polyester powdercoat finish, oven dried. The enclosure is vented with fine mesh protection to prevent the insertion of foreign bodies. Knock-outs are incorporated to simplify installation.
Enclosure dimensions: 332H x 372W x 395D mm.

Rating
3 kVA single-phase continuously rated double wound transformer, manufactured in accordance with BS EN 61558 Parts 1 and 4 but with an earthed secondary. The transformer is designed to have a low inrush current but should be fed from a Type “D” MCB or motor rated fuse.

Primary Volts
Tapped at 230.240.250 and 260.

Secondary Volts
230 Centre-tapped with restricted earth. The maximum line to earth voltage is 115 volts.

Restricted Earth
A 12 kΩ current limiting resistor is incorporated in the CT to E path, which restricts the maximum line to earth current to 10 milliamps.

RCD Protection
Fitted on the secondary with a 16 amp double-pole MCB with shunt-trip working in conjunction with a 5 mA sensitivity earth leakage sensor providing Type AC RCD protection.

Distribution
Fitted with 2 no. 10 amp double-pole distribution MCBs.

Testing
We have become aware that there are no commercially available RCD test sets on the market that are compatible with the output of a Safe Supply Unit (SSU). Therefore, unless the installer already has a suitable test set, it will not be possible to complete the normal range of RCD related tests at the time of installation or when carrying out periodic testing.