Fused, timed extractor fan wiring

[HalfEatenFlapjack]

I, er, my mate wants to have a timed extractor fan (in-line, in the loft space) in my bathroom, operated off the light switch. The fan requires protection from a 3A fuse. The lights (actually 5 downlights) do not. Will this wiring work?

Hypothetically speaking, obviously, as it's probably notifiable.

Thanks!

Fan/Light/Fuse wiring diag

• HalfEatenFlapjack
• 8 Jul 2014
• 1

 

[AndyPRK]

Yes it will work.

If your FCU is switched, you don't really need the 3 pole switch, but if your going to fit the 3 pole switch in the loft with the fan it would be worth while having.

 

[EFLImpudence]

You don't need any junction boxes - let alone three.

Connect the wires to the respective accessory terminals.

 

[JohnW2]

I, er, my mate wants to have a timed extractor fan (in-line, in the loft space) in my bathroom, operated off the light switch. The fan requires protection from a 3A fuse. The lights (actually 5 downlights) do not. Will this wiring work?

Although the lights don't require a 3A fuse, there would be no harm in running them (as well as the fan) via the 3A fuse - which would mean that you would only need a single-pole pull switch.

Hypothetically speaking, obviously, as it's probably notifiable.

Only notifiable if any of it is in bathroom 'zones' - which is unlikely if your ceiling is more than 2.25m above floor level. The circuit probably needs to be RCD-protected, though - so if it isn't already, that may have to be addressed.

Kind Regards, John

 

[HalfEatenFlapjack]

Thanks. We have an old-style consumer unit with fuse wire in, rather than RCDs. We do intend to get this upgraded at some point in the future. Is it possible for a diy-er to protect an individual 'system' (like this lighting/fan system) with an rcd? I don't want to be fiddling with the consumer unit, hypothetically or not.

 

[AndyPRK]

You can get RCD FCU's, so you could fit one of those instead of the FCU.

Not sure I would bother, but to comply with the regulations, before your CU is upgraded its what you should do.

 

[EFLImpudence]

Thanks. We have an old-style consumer unit with fuse wire in, rather than RCDs. We do intend to get this upgraded at some point in the future.

As the fan is in the loft and if the light is higher than the 2.25m limit of zones I would not worry about it.

 

[JohnW2]

Thanks. We have an old-style consumer unit with fuse wire in, rather than RCDs. We do intend to get this upgraded at some point in the future. Is it possible for a diy-er to protect an individual 'system' (like this lighting/fan system) with an rcd? I don't want to be fiddling with the consumer unit, hypothetically or not.

Even if it were not hypothetical, and even if you were prepared to 'fiddle in the CU', you would not be able to put an RCD into an old-style CU such as you describe.

The regulations require that all circuits in a bathroom be RCD protected. Although that does not apply retrospectively, it does apply to any circuits which you do any work on. If you wanted to be fully reg-compliant, you could RCD protect just the light+fan by using an RCD CU, rather than an ordinary CU - but it would obviously have to be reasonably accessible (so that it could be tested and, if necessary, reset) - but not within any of the 'zones' of a bathroom. I suppose much the same really goes for an 'ordinary' FCU, since you might conceivably have to replace its fuse. Where were you proposing to locate the FCU?

Kind Regards, John

 

[JohnW2]

Thanks. We have an old-style consumer unit with fuse wire in, rather than RCDs. We do intend to get this upgraded at some point in the future.

As the fan is in the loft and if the light is higher than the 2.25m limit of zones I would not worry about it.

Is this you being pragmatic/sensible, or do you interpret the regs differently from me? When 701.410.3.6 calls for RCD protection of all circuits (which presumably would include the lights {and maybe FCU} and pullswitch, even though the fan is in the loft) 'in the location' , I take that to mean 'in the room', not just 'within' zones. Do you have the same view, or do you have a different interpretation of 701.1?

Kind Regards, John

 

[HalfEatenFlapjack]

In the loft next to the fan. In the airing cupboard (which is outside the bathroom) would also be easy to access. I wouldn't know what parts to buy though.

 

[JohnW2]

In the loft next to the fan. In the airing cupboard (which is outside the bathroom) would also be easy to access. I wouldn't know what parts to buy though.

The airing cupboard would probably be most sensible. As for 'what to buy', let's see how EFLI responds to my question, first - he seemed to be suggesting that you shouldn't bother with RCD protection.

Kind Regards, John

 

[EFLImpudence]

Is this you being pragmatic/sensible, or do you interpret the regs differently from me? When 701.410.3.6 calls for RCD protection of all circuits (which presumably would include the lights {and maybe FCU} and pullswitch, even though the fan is in the loft) 'in the location' , I take that to mean 'in the room', not just 'within' zones. Do you have the same view, or do you have a different interpretation of 701.1?

Yes, pragmatic and sensible.

I was using the zones as perceived 'danger area' - therefore not notifiable so not really relevant.

I presume you meant 701.411.3.3.

The work being undertaken could be completed without touching the actual wiring IN the bathroom.

However, it's not so:
Would you consider it mandatory to install an RCD solely because you had fitted a new switch?
If not, would you consider it mandatory to install an RCD because you had connected a new cable to the light fitting?

I presume you would and do.

I just think that the work has no effect on the bathroom.
If you read 701.411.3.3 as it is worded then RCDs should be fitted to all special locations now regardless of any work is being done.

 

[JohnW2]

Is this you being pragmatic/sensible, or do you interpret the regs differently from me? ....

Yes, pragmatic and sensible. ... I was using the zones as perceived 'danger area' - therefore not notifiable so not really relevant.

I certainly agree that is pragmatic and sensible.

I presume you meant 701.411.3.3.

Sorry, yes I did - a rather surprising typo (particularly given that I had to look up the reg number!).

Would you consider it mandatory to install an RCD solely because you had fitted a new switch? If not, would you consider it mandatory to install an RCD because you had connected a new cable to the light fitting? ... I presume you would and do.

Your reference to "you" rather confuses this. As is often the case, what I personally would 'do' (and not necessarily talk about here) and what I would advise someone (at least 'in public') about what I believe would be strictly reg-compliant are not necessarily the same thing!

I just think that the work has no effect on the bathroom.

... and I agree.

If you read 701.411.3.3 as it is worded then RCDs should be fitted to all special locations now regardless of any work is being done.

You're talking as if the regs are retrospective, which we know they aren't. However, I think that Mr Jobsworth might say that the moment one 'does anything' to something which is 'an LV circuit in the location', then strict compliance with that regulation requires that the circuit should be RCD protected.

I am certainly a pragmatist, and would also like to think that I am sensible. It's therefore not hard to work out what I would probably do if I were in that situation - and the same may well be true of you. What I/we should advise someone else is perhaps not so straightforward.

Kind Regards, John

 

[EFLImpudence]

Yes, ok but as it is not notifiable there will be no jobsworth therefore it is a question of where to draw the line for the OP.


Just OOI - should anyone fit an RCD to this lighting circuit because of the reasons you state, should they also (with their thinking, not yours) also fit RCDs to other circuits in the bathroom because 701.411.3.3 says all circuits etc.?

 

[HalfEatenFlapjack]

So should I use one of these instead of an FCU?

http://www.tlc-direct.co.uk/Main_In...tected_Range/RCD_Protected_Range_2/index.html