A shower fan light is a very good way of complying with the electrical regulations and providing light and ventilation in the optimum place, that is where the moisture originates.

If you purchase on of the shower fan light kits that are available you will receive a fan, an internal grill with an integral light and transformer, an external grill and some ducting to join them altogether plus some plastic ties to couple the ducting to the grills and fan.

In order to comply with the regulations you will also need one or possibly two fan isolators and some connectors. The regulations state that local isolation must be provided for any mechanical item, this needs to be close to the equipment and so in the case of our fan the isolator needs to go into the loft. You will also need some 1.5mm 3 core and earth cable.

Take the fan kit out of the packaging and ensure that all the pieces are there. Now you have to decide on exactly where the fan is going to be placed in the bathroom, over the bath or shower is ideal but before you cut any holes in the ceiling you will have to determine if any joists or other obstacles are in the way. To do this you will have to get into the loft and have a look. It’s a good idea to poke a fine screwdriver through the bathroom ceiling in the proposed location and check you have clearance above.

Once the location is decided you can cut a hole in the ceiling, this will be 4 to 5 inches in diameter. You can use a plasterboard saw or preferably a hole saw of the right size. Once the hole is cut, fit the internal grill with the integral light. This will generally have some plastic clips which grip the ceiling to hold it in place.

The fan motor and light will require power and this will come from the existing light fitting. Turn off the lighting circuit to the bathroom at the consumer unit!

There are numerous light fittings available but for simplicity we will discuss the normal batten holder or ceiling rose. Unscrew the cover and you will see the wiring, this will normally have the terminals marked, live, neutral and switch, plus a terminal with all the earths in (green/yellow). For the fan light we will need to connect a wire to each of them.

I find it easier to push a length of the 3 core and earth cable up through the hole in the back of the light fitting and pull it up from above so push enough cable up to reach the fan position.

Now, in the loft, you will see the spigot from the back of the fan and hopefully your cable. You may have to dig around under the insulation to find them. Fix the fan motor to a convenient piece of timber in the vicinity of the grill, noting the airflow direction, and screw a plastic switch box next to it. The cable from the bathroom light will go to the switch box, try to keep the cable above any insulation but not laying where someone may trip or stand on it.

You now have the basics set up. Connect a piece of flex to the fan motor, this should be four core, although the fan does not require an earth it is not permissible to use the green/yellow core as a live. In the fan will be three terminals marked, L, N, S(T) connect the flex.

The flex cores will be brown, blue, black and green/yellow. Connect as following:

Brown- Live (L)

Grey- Neutral (N) Sleeved with blue.

Black- Switch (S or T) Sleeved with brown

Bring the flex to the switch box. The integral light will have a transformer attached and you need to run a cable from the switch box and connect it to the transformer
with an approved connector.

At the switch box you now have three cables, feed (from the bathroom light) and two switched cables (to the fan/integral light). Most boxes have an earth terminal so you can go ahead and screw all the earths into it, having sleeved the bare copper with green/yellow sleeving. Connect the other cables like this.

Feed cable goes into the top three terminals in the back of the fan isolator as described for the fan. The other two cables will go into the bottom terminals.

Fan flex :

Brown- Live

Blue- Neutral

Black (brown sleeving) S.

The integral light cable will connect:

Brown- S

Blue- N

Fit the isolator to the switch box and turned on.

Now fit the ducting between the fan and the internal grill and fasten. Connect the ducting to the other side of the fan and bring out to a convenient place, possibly though the eaves or through a hole in the wall. You are now finished in the loft.

Go back to the bathroom and cut the cable to length and strip it back to expose the cores. Sleeve the bare copper earth with green/yellow sleeving and sleeve the black core with brown and the grey core with blue sleeving. Connect to the light in the same way as the fan isolator.

Turn the power on at the consumer unit. In the bathroom turn the light on and you will hear the fan start up and the integral light will come on. Turn the bathroom light off, the integral light will extinguish but the fan will run on for about 15 minutes. Go outside and fit the external grill. Now you have a shower fan light to reduce the condensation and provide light where you need it.

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