A fan isolator switch is a specialist electrical switch used to control an extractor fan. It is a triple pole switch designed to switch the live, switched live, and neutral connections. It can also isolate them all, for safety reasons.
Why Do You Need a Fan Isolator Switch?
Fan extractor fans are connected to bathroom lighting circuits. They are used to continue to provide power to the fan even when the light is turned off.
Where is a Fan Isolator Switch Installed?
Regulations require a fan isolator switch to be installed in an accessible location outside the room where the fan is fitted, often above the bathroom door or nearby on the landing. This positioning ensures that the fan can be isolated without entering a room where there may be higher risks due to moisture.
How Does a Fan Isolator Switch Work?
Unlike standard switches, a fan isolator has three poles:
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Live
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Switched Live
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Neutral
When switched off, it disconnects all three, ensuring the fan is completely isolated from the supply.
Do All Fans Need an Isolator Switch?
Yes — UK wiring regulations state that extractor fans must have a means of isolation. A dedicated fan isolator switch is the recognised and most practical way of achieving this, giving both safety and convenience.