Bathroom Extractor fan Switch?????

The fan requires L + N + SWL   (cpc parked at fan position if not used) on the presupposition that you want the fan to come on with the light- thus the rose in the bathroom will give you this if wired correctly and stuff. The only thing is -  is that maybe to satisfy regs then a fan isolator will be needed in the circuit - don't know nuffin about the unswitched spur because it would make the installation non compliant unless it was a Integral PIR type fan.

 

You don't have to have an isolator for the fan if there is a window in the bathroom. The fused spur is a bit more of a problem as you will have both a permanent live and a switched live if wiring fan to come on with the light. I usualy wire so that both the fan and the light go through the fused spur, failing that use a fan which doesn't specify that a 3a fused spur must be fitted!  However, most fans specify a dp switch so a switched spur would satisy that requirement.

 

That is very confusing, or could be construed the wrong way, seneca.

Just saying.

Mr. HandyAndy - Really

 

I have a 4 scene dimmer control unit for lighting in my bathroom ( RCBO ) and fitted a separate 1 gang 1 way switch outside the bathroom which is adjacent to the dimmer unit to control my ceiling fan. Thinking about fitting an occupancy sensor that was an optional extra with the fan, wonder if that would satisfy the regs........ With regard to safe isolation, still need to fit a DP fused connection unit.

 

It would work ok but there would be no 3a fuse protection for the switched live to the fan.

 

Yes that would be ok.

 

The fan will only run with the light turned on Reef which rather defeats the condensation thing. Are you running a 10 Amp mcb on the lighting circuit?

Not being funny or owt but why not use a fan with integral PIR? - I use one in my bathroom and its brill although I did whip in a 3c + E to it as a matter of course. when only 2c + e was in fact needed. The fan isolator is outside the bathroom , and the fan (with isolator) and light  is run off a dedicated Mcb off RCD side of split loader and pulled off of loop in box.

 

Reef  The picture of the unswitched fused spur using the permanent live and neutral to fan . Somebody could think by taking the fuse out, the fans isolated but its not as the fans still live when the light is on .You would have to put the unswitched fused spur on the supply to just the bathroom light and the timer fan only . Which means a lot of alterations but can be done. 

 

Can you not fuse the live feed before it gets to the bathroom light? Then you can just wire from the light straight to the fan.

As far as isolation for maintenance is concerned, the fan needs to have all pole isolation in the same room, or lockable all pole isolation if not. I would say a double pole main switch on a consumer unit, or a switched fused connection unit on the bathroom lighting feed satisfies? Being in a bathroom, it will need rcd protection too, so perhaps an rcd fused spur for the lighting feed outside the bathroom satisfies all requirements?

 

Fan doesn't need all-pole local isolation if there's a window in the room because they can maintain it in daylight!

 

Any particular shape or size of window... Say it had blinds and was a dull day......Any specified minimum Lux levels stated for safe working conditions......Sorry just being pedantic..

 

The best way to wire a timer fan from a spur is to utilse two live feeds from the load side of the spur. One live goes directly to the fan, the other goes to the switch. The lighting and the fan effectively become fed from the spur. If you did it this way the temptation to switch off the fan is reduced because in doing so they would lose the light too. This method also provides 3A protection to the fan and obviates the need for a triple pole switch (assuming a dp spur L/N is used). I believe new-builds adopt this approach too. Fans are useful for removing smells as well as venting for showers so I would avoid a standard switched fan and go for the timer as originally planned.

Edit: As JP pointed out it may be worth investing in a ceiling PIR for the fan switched separately from the lights. But still adopt the spur as explained. (Good point JP )

 

Yeh, and as long as it's between 9am and 4pm on a bright winters day, otherwise 9.30 to 3.30.

This also involves turning off the whole CU as MCB for lights isn't double-pole.

Mr. HandyAndy - Really

 

Anyway, Humidistat fan. Spur from socket outside bathroom to FCU unswitched, 3A fuse, to fan. Automatically comes on when steamy, off when clear(or supposed to).

Mr. HandyAndy - Really

 

The truth well told !