Bathroom Extractor Fan

[Shock Doctor]

Hi all,

Ive got an extractor fan to fit in a bathroom. Im planning to run it from the light fitting to and fcu out of zones for isolation and then to the fan. However there is no rcd protection on the CU. Customer doesnt want a CU change. I would like to know if running the lighting circuit through a RCD FCU next to CU would be sufficient to comply with the regs.

Any advice gratefully received.

 

[telectrix]

sounds ok to me. or if it's a modern CU (MCBs), RCBO the ligthting. 3 pole isolator outside zones.

 

[MFHEng]

As above

 

[sjm]

You could use an RCD fcu to supply the bathroom lighting circuit, either at the cu or local to the bathroom. This will fuse down to 3 amps for fan and give RCD protection. Then use 3 pole isolator for fan.

 

[Shock Doctor]

Thanks for the quick replies. Unfortunatly its an old CU so no mcb to rcbo option. 3 pole isolator outside zones it is! Was reading some old posts on here regarding extractor fans and they mentioned fusing down to 3a wasnt sure if this was a reg I hadnt found yet or equipment protection so thought Id put a thread up and find out.

Thanks again, as a relative newbie its nice to confirm Im getting it right first time!

 

[telectrix]

if fan is on lighting circuit, no need to fuse down as it's alredy fused at 5A or 6A. 3 pole isolator is needed so as to isolate both the permanent live and the switched live to the fan for maintenance purposes. assuming timer fan. if fan is just to come on and off with light, i.e. non timer, no need for isolator

 

[sjm]

There have been threads on this before. Manufacturers installation instructions usually require a 3 amp fuse for extractor fans, regardless of the supply circuit fusing. This fuse would probably fail first as 1.5 x rated current is still only 4.5 amps not 5 or 6 amps. Best advice seems to be to follow manufacturers installation instructions.

Hope this helps.

 

[telectrix]

i stand corrected

 

[Shock Doctor]

This place is magic. I learn something new every time I visit!

 

[telectrix]

and not a sign of harry potter