Timed fans are extremely useful, especially in bathrooms or other areas where odours or condensation might be generated, because they are programmed to continue running for a short period of time after the light switch has been turned off, thus helping to clear the atmosphere.
The fan’s in-built timing device has to have a three-core connection plus an earth terminal, to allow it to achieve the overrun. It also has to be able to be turned off independently, by using either a pull switch situated in the bathroom or an isolation switch mounted conveniently outside the bathroom.
As with any other electrical installation project, it is imperative that the power is switched off before making any connections.
From the ceiling rose light fitting, a green and yellow covered earth wire is run to the appropriate terminals on both the isolation switch and the fan.
Then, numbering the terminals on the isolation switch 1, 2 and 3 and the terminals on the fan 4, 5 and 6, the blue coloured neutral wire from the ceiling light rose is connected to terminal 3 on the isolation switch and to terminal 6 on the fan.
The red, live wire, from the light fitting is connected to terminal 2 on the isolation switch and to terminal 5 on the fan. This is then followed by connecting the yellow, switched live wire to the remaining terminal on both the isolation switch and the fan, i.e. terminals 1 and 4 respectively.