Fan Fuse

[Pinto Baz]

I have just been given a periodic test report with a code 4 fault: Bathroom fan not fused at 3A. The fan is fed from the lighting circuit which is supplied via a 6a MCB. Does anyone fuse down fans fed from lighting circuits? Does anyone make a triple pole fan isolator with double pole fusing for timer fans?

It's only a code 4 so I will ignore it, just it's a new one on me!

 

[solo2771]

would have thought the 6 amp was good enough protection but would have a means of isolating fan without cutting light circuit and would fuse fan depending on spec of fan.
Paul

 

[Pinto Baz]

The triple pole fan isolator is there, it's just the fusing issue. I've never done it and never noticed anyone else doing it.

 

[markharris]

I thought you only need to fit an isolator if there is no windows in the room (no natural light available)

 

[mechelec]

It depends if the fan manufacturer specifies a 3A fuse to be fitted. Some do some dont, it is not in the wiring regs anyway.

 

[MarkieSparkie]

The only reason I can think of for requiring local 3A fusing would be in a situation where there is a conductor CSA transition, eg. the lighting circuit wired in 1.5 T+E and then the fan circuit from the lighting point (or JB) is run 1.0 T+E.
If this is not the case the inspector appears to of had a 'blonde moment'.

 

[Octopus]

Fitting a fan isolation switch is good practice, irrespective of whether there is a window and I always fit one.

If you didn't fit one, how would you isolate it when it goes wrong? Flick the lighting MCB - that's OK as long as its daylight!

 

[Ace]

The instructions will specify what size of fuse the circuit needs to be rated at, and the need for tripple pole isolation depends on what type of fan is installed. IE if it is selv with a timer and the transformer and isolation for the fan / transformer are all local, I would be happy to see a suitably labeled switched fused connection unit before the transformer. If the fan is not selv and does require a 3rd conductor to operate a timer etc I would think a 3pole isolator would be required.

 

[ezzzekiel]

the fusing down for fan is often per manufacturers instructions but has nothing in bs7671 so does not warrant any code.

 

[telectrix]

ezzzekiel is, as usual, correct. codes are for deviations from bs7671, not manufacturers whims.

 

[tonys]

Another PIR not worth the paper its written on.

 

[telectrix]

Another PIR not worth the paper its written on.

why so? the guy that did the PIR might just have a different view on whether to code it. doesn't mean his PIR is worthless.

 

[tonys]

How can something carry a code when there not a regulation to back it ?

The evidence that to many people with not enough knowledge of BS7671 are carrying out PIR's can be verified by the amount of basic questions being asked on the forum, and I bet there's hundreds who don't use the forum just cast an opinion with no regulation to back it.

Maybe I should not have said Another PIR not worth the paper its written on but still don't hide the facts of the above.

 

[telectrix]

ah, see what you mean. however, whenever a deviation from BS7671 is mentioned on this forum, there's frequently a difference of opinion over what code if any it should be given. sometimes it's down to interpretation of the regs. sometimes down to poor knowledge.

 

[Smugley]

There should be a column in the PIR report to enter the BS7671 regulation number that each code 4 refers to.

 

[Pinto Baz]

Thanks guys, I was just wondering if anyone did fuse down their fans, and the impression I am getting is that they don't. (Which is the impression that I have always had.) The only way I can see to do it to with this already fitted 230v timer fan would be to chop a fuse spur in next to the switch, which would look awful, and fuse down all the bathroom lights with the fan.

I would always want to see an isolator on any piece of fixed equipment, and I am sure there is a reg for that,who wants to wait for an electrician to arrive before you can have the lights back on

 

[telectrix]

Thanks guys, I was just wondering if anyone did fuse down their fans, and the impression I am getting is that they don't. (Which is the impression that I have always had.) The only way I can see to do it to with this already fitted 230v timer fan would be to chop a fuse spur in next to the switch, which would look awful, and fuse down all the bathroom lights with the fan.

I would always want to see an isolator on any piece of fixed equipment, and I am sure there is a reg for that,who wants to wait for an electrician to arrive before you can have the lights back on

be even worse if you hads to wait for a plumber to turn up.

 

[nickblake]

I must admit i do use a fused spure to supply the bathroom lights and fans , this was something id heard thta fans require a fuse for protection ,so during my elecsa anual survey i asked the question and the reason for it was due to a fire where a guy had died caused by the fan siezing ,i have come across this on several occasions in fact one was a shop in manchester that caused ove £300,000 worth of damage ,as has been said its not in the regs but down to manufacturers requirements which should be taken into consideration when installing fans or within the design ,the spark in the case of the fire was fined for neglegence ,although it wouldnt warrent a code , us sparks should read the instructions and adhear to them

 

[Pinto Baz]

Food for thought. Not sure that fusing down from 6A to 3A would have made any difference though, fitting fans with a thermal cut out seems more likely to me to prevent a fire.

 

[SirKit Breaker]

This thread could run and run. and there are some interesting replies. I was told that the manufacturers instruction take precedence over the wiring regulations.
So if you install say a shower, the manufacturers instructions will say "Must be installed in accordance with the installation instructions, and must be protected by a residual current device, if in doubt contact a qualified electrician" or words to that effect. That tells me that it must be fitted to the current edition of the wiring regs, and if there is no RCD then one needs to be fitted. The fan scenario is the same, if the instructions say fit a 3 amp fuse, then you have no choice but to fit a 3 amp fuse. If it doesn't then you done need to. Either way i will just throw some more fire on the argument so to speak. If it is wired into the lighting circuit on a 6a MCB etc, then that has to be far safer in my mind than fitting a FCU with a 3amp fuse. Why, because when the fuse blows, Mr homeowner will bang a 13amp one in cos that is all he has, 6amp MCB is safer all day long than a 13amp 1361 fuse.

Cheers.........Howard