John asks this question, which concerns a bathroom fan having a permanent feed, neutral and switch wire – and an owner who doesn’t want any type of isolator installed! It has been answered by SELECT (Theme – Regulations and Legislation):
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Question: I’m currently re-wiring a property and had a query regarding the requirement for an isolator switch. Does a bathroom fan, which needs a permanent feed, neutral and switch wire, also need a three-pole isolator switch installed to comply with the current regulations?
I have always installed a switched fused unit or a three-pole isolator for any type of fan, depending upon whether the fan required a permanent feed or not. The problem I have is that the client does not want any type of isolator installed for the fan, not even an extra pullcord.
Am I allowed to install a bathroom fan without installing an isolator switch and still comply with the current regulations?
Answer: The provision of isolating devices for extract fans in bathrooms or shower rooms is not specifically addressed in BS 7671.
A fan isolator mounted adjacent to the fan would fulfill the requirement for switching off for mechanical maintenance.
Regulation 537.3.2.2 requires the open position of the contacts of such a switch to be clearly indicated.
Taking all of the above into consideration the following is therefore recommended:
Extract fans having a ‘run-on’ timer:
A BS EN 60947-3 fan isolator mounted adjacent to the fan would provide the appropriate means of switching off for mechanical maintenance. Where the isolator switches both the switch wire and permanent line conductor, this would also provide a means of local isolation where access to live parts is required.
The isolator should be located adjacent to the fan outwith Zones 0, 1 and 2 in accordance with Section 701 of BS 7671:2008 (2015).
The switch need not necessarily interrupt the neutral conductor.
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