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In this guide we take a look at how a timed fan unit or extractor fan with a built in timer is wired up, read on to find out exactly how. Safety Regulations for Electricity Strip both ends of the cable to suitable lengths (manufacturer should state this in their instructions, if not see our stripping cable project here) and connect the switch end cable to the correct terminals.
When it comes to the type of extractor fan found in a bathroom there are essentially 2 different types; time switched and non-time switched. The main difference between the 2 is that with a timed switch, when the unit is turned off it will run on for a set amount of time to finish clearing the bathroom and when the time expires it then turns itself off. Next, the fan should then be connected using 3 core and earth cable (depending on the model the earth may not be required), with the extra cable being used as the switch-live (SL). This wiring diagram shows an easy to follow configuration for a bathroom extractor fan fitted with a timer, that’s not going to be turned on by the existing light switch. Instead, we are going to install a new switch that will turn the fan on and off.However, if you are simply replacing an existing extractor fan because it’s broken down or failed then you are allowed to do this under Part P. This then enables the independent pull-cord switch to trigger the fan, and allow it to run on, in accordance with the timer setting when the fan is switched off.
In this instance, the switch live (SL) connection is not used but it is recommended that a 3-pole switch is still fitted as it would allow the circuit to be reconfigured to work with the light switch in future if desired. If installing an inline fan, this will need to be positioned and screwed down to a flat and level surface, ideally between the point that air is being extracted and then being expelled.
Types of Bathroom Extractor Fan Power Supply
This briefly covers the 2 main different types of extractor but for a full and detailed run down, see our types of extractor fan project here. Types of Bathroom Fan Switch Configuration If this is in a ground floor bathroom, you may need to pull up some floor boards to access and wire up. If you are installing an inline fan then you will also need to install the associated pipework that will carry the moist air from the source to the outside.
In a similar manner, the junction box for the live feed is then wired to the FCU, again, each wire connected to the correct live, neutral and earth terminals.For both different types of units they can also be tuned on and off through normally 2 different means; they are either wired into the light, so that when it’s turned on the extractor comes on also or they have their own dedicated switch, normally as an isolator outside the bathroom above the door or inside as a pull cord switch. When wired to its own switch, the switch itself will either be located outside of the bathroom, normally above the door or it can be inside as long as it’s in the correct zone and is a pull cord switch.
