3 amp on the extractor fan?

If the manuf. doesn't stipulate a 3 amp fuse just rely on the 6 amp mcb.

 

Yes,if nothing stated, a 6amp is fine. If it is stipulated, to comply with BS7671, you must follow manufacturers install instructions.

For timed fans, this requires thinking outside the box.

 

Very strange that a manufacturer hasn't put a fuse rating. I mean, I've installed a fan on the 32A ring(I did put in a 3A fuse), but without the info, any diyer might put it on a 13A.

Mr. HandyAndy - Really

 

They usually say use a 6 amp mcb, even those that don't state a 3 amp fuse handy.

 

Strange thing is the fuse is there to protect the cable not the thing is attached to, according to the Holy Bible 7671.

 

In this application, though, it is there in case the fan catches fire. The fan draws so little current (and its a fixed load) so it can't overload the circuit fuse. It is unlikely to short out, but, it can jamb or the motor can jamb causing overheat and fire so its there for fire protection as far as I am aware.

 

.......and the fuse still won't blow!


Mr. HandyAndy - Really

 

I don't suppose a 1 amp clock fuse would be much better. But looking at the TLC site these now come with a 2 amp fuse. I suppose fan motors are pretty dangerous things from a fire perspective.
In our new kitchen our cooker hood cable goes inside the chimney( but outside of the convoluted flue pipe!) and plugs into a switched 13 amp socket which will be above the suspended ceiling when it is fitted access being through a removable panel. However in the event of fire I could isolate at the CU within a few seconds. I know that I should have a more accessible means of emergency isolation but I will have to see what my electrician says when he checks the complete installation.

 

Well it should! If the motor jambs it will draw more current and overheat, hence the 3A. I agree it is not guaranteed but better to have something there than nothing at all. It is to prevent fire happening not after the fire has started! If fire has already started then its too late.

 

UP Sorry I cannot quite follow your argument.
If the fan motor jams and causes a fire then it wont matter if the fuse blows or not because the house may burn down anyway.
The fuse protects the electrical installation.
The readily available isolator which I may not have ( see my post above) should enable the fan to be switched off as soon as you are aware it has jammed thus avoiding a fire.

 

The idea is that if the fan jambs it will draw excessive current which will blow the 3 amp fuse before the fire starts!

 

As stated fuses are to protect the cables so the only issue is manufacturers' instructions being complied with. It offers absolutely no safety benefit whatsoever, and will not blow if the fan jams.

If the fan needs fusing for protection then it should be fitted by the manufacturer, and certainly wouldn't be provided by a 3A BS 1362 fuse.

 

Can anyone explain, where this 3 amp or 5 amp fuse would be sited. One has to have an Fan Isolator outside the Bathroom. There is switched live and Permenant live wires, so how to connected these wires to fuse? Regards

 

Basically you would have to loop your feed through an FCU, and take the fuse side to your luminaire, and from there run your cable with permanent and switched phase/line and neutral, and cpc, to your fan (perhaps through a fan isolator).

 

Perhaps one of these if you fit the MK Sentry range:

http://www.qvsdirect.com/mk-sentry-3-amp-b-type-single-pole-mcb

 

Any one uses inline fusesholders on live wires, and fit with correct amperage of fuse?

 

Only if I can fit it into an enclosure. (eg the fan housing in your case perhaps?)

 

Thanks Seneca..Xpelair fan I'm trying to fit, manufacturer asking for 5Amp fuse...connecting to lightening circuit with 6Amp mcb..RCD protected. In line fuse in wiring seems easiest option.