Bathroom Extract Fan Isolation

[charlie76]

A customer of mine wants a bathroom fan installing but on its own pull cord so they can control when it is on and off. No run on time required just on and off. Is it ok to come straight off the lighting circuit in the bathroom and use the pull cord as the means of isolation for the fan?

 

[alanl]

It's OK coming off the lighting, (so long as it has RCD protection) but it wouldnt be isolated when turned off via the pull cord would it?
Does it need local isolation?
BS7671 doesnt require local isolation except for emergency switching.

 

[charlie76]

It's OK coming off the lighting, (so long as it has RCD protection) but it wouldnt be isolated when turned off via the pull cord would it?
Does it need local isolation?
BS7671 doesnt require local isolation except for emergency switching.

Probably not. According to the IET Electricians Guide to the B. Regs page 74 "An extractor fan supplied from a lighting circuit for a bathroom without a window should have it's own means of isolation" they then go on to say so it is not being maintained in the dark i.e. if you turn the 6A lighting breaker off. I take this to mean, given that the bathroom I am working on does have a window, that it does not need local isolation.

 

[kenny7askew]

if its on its own pull cord it will be ok but may need to be fused down depending on make of fan

 

[Andy78]

Probably not. According to the IET Electricians Guide to the B. Regs page 74 "An extractor fan supplied from a lighting circuit for a bathroom without a window should have it's own means of isolation" they then go on to say so it is not being maintained in the dark i.e. if you turn the 6A lighting breaker off. I take this to mean, given that the bathroom I am working on does have a window, that it does not need local isolation.

Do building regs apply in this situation ? It would be wise however to supply a DP FCU for this fan.

 

[charlie76]

Do building regs apply in this situation ? It would be wise however to supply a DP FCU for this fan.

Yes part f ventilation.

 

[HappyHippyDad]

It's OK coming off the lighting, (so long as it has RCD protection) but it wouldnt be isolated when turned off via the pull cord would it?
Does it need local isolation?
BS7671 doesnt require local isolation except for emergency switching.

There have been many threads on the subject of isolation for extractor fans. I think the main concensus is that the MCB in the CU would meet the regs (not great practice though), however, in this case where the fan will not be on an overun timer a DP pull switch could act as isolation, you could use one such as this PULL SWITCH CRABTREE DP 16amp with p/light | eBay.

 

[Andy78]

Yes part f ventilation.

So the work is part of new build work or major structural renovations that fall under building regulations ?

 

[stevey1983]

Yes, just use a fan isolator pull cord. Local isolation and switching achieved in one. Job done

 

[Richard Burns]

The building regulations would apply to any alteration of a fixed service.
Whether it would be notifiable to building control is dependent on the locations of the wiring (in or out of zones), but the installation of a fixed speed independent intermittent extract fan is not notifiable.

For the fan the manufacturers instructions very often ask for double pole isolation of the supply, which can be done as HHD says above with a DP pull cord, if they also require the supply to be fused down then a fuse should also be installed.

 

[Andy78]

The building regulations would apply to any alteration of a fixed service.
Whether it would be notifiable to building control is dependent on the locations of the wiring (in or out of zones), but the installation of a fixed speed independent intermittent extract fan is not notifiable.

For the fan the manufacturers instructions very often ask for double pole isolation of the supply, which can be done as HHD says above with a DP pull cord, if they also require the supply to be fused down then a fuse should also be installed.

Could you expand on that please Richard ? This goes against my current understanding of the building regs that they only apply where building work as defined by the building regs is taking place.

 

[davesparks]

Yes a normal pull switch will be fine as a single pole isolator

 

[Octopus]

My 2 pennies worth!

If, and I say if LABC are involved, then they will almost certainly be asking for a fan with a timer. If this is the case I would ask them!

 

[Richard Burns]

Could you expand on that please Richard ? This goes against my current understanding of the building regs that they only apply where building work as defined by the building regs is taking place.

I would agree with your statement that the building regulations apply to "building work".
However as extracts from the regulations show below the alteration of an electrical fitting is "building work".
However there is a limitation on requirements (8.) that appears to negate Part P, but if that were the case then the approved documents would be pointless (hmmm!)
Schedule 1 is the parts of the building regulations.


2.—(1) In these Regulations, unless the context otherwise requires—
…..
“building work” has the meaning given in regulation 3(1);
…..
“controlled service or fitting” means a service or fitting in relation to which Part G, H, J, L or P of Schedule 1 imposes a requirement;


Meaning of building work
3.—(1) In these Regulations “building work” means—
(a) the erection or extension of a building;
(b) the provision or extension of a controlled service or fitting in or in connection with a building;....





4.—(1) Subject to paragraph (2) building work shall be carried out so that—
(a) it complies with the applicable requirements contained in Schedule 1; and
(b) in complying with any such requirement there is no failure to comply with any other
such requirement.





7. Building work shall be carried out—
(a) with adequate and proper materials which—
(i) are appropriate for the circumstances in which they are used,
(ii) are adequately mixed or prepared, and
(iii) are applied, used or fixed so as adequately to perform the functions for which they are designed; and
(b) in a workmanlike manner.





Limitation on requirements
8. Parts A to D, F to K, N and P (except for paragraphs G2, H2 and J7) of Schedule 1 shall not
require anything to be done except for the purpose of securing reasonable standards of health and
safety for persons in or about buildings (and any others who may be affected by buildings, or
matters connected with buildings).

 

[Andy78]

As you say, clear as mud and apparently contradictory.
If the building regs applied to all alterations of electrical equipment and services, all altered switches and sockets in dwellings would need to be at the heights prescribed in part M ?

 

[Richard Burns]

The building regulations as a whole apply to all "building work", but not every one of the individual building regulations apply to all building work, there are exclusions and areas only applicable to certain situations.
For instance Part M of the building regulations only applies to new dwellings or dwellings undergoing "material alteration" and does not apply to existing dwellings or extensions to existing dwellings.