Wiring up an extractor fan

[Keitai]

My previous extractor fan had a plug on it. This new one has no earth and they're talking about a double pole switched fused spur outlet in the instructions.

Can I just stick a plug on the live and neutral wires and ignore the earth and off I go?

 

[HERTS P&D]

Here we go again!

Andy

 

[EFLImpudence]

Yes of course.

The plug has a fuse in it and pulling out the plug is better than a switch.

 

[Taylortwocities]

Just put a 3A fuse in the plug and you are ready to plug it in.

Meerkat

• Taylortwocities
• 11 Dec 2009
• 53

Simples!

 

[winston1]

Or any other size fuse available as it is to protect the cable not the fan. This item is sold in Europe as the instructions imply and in Europe the only protection would be a 16a MCB in the CU.

 

[Taylortwocities]

The installation instructions for the UK - shown above - say that the fuse should be 3amp.
As this is a forum aimed at DIYers, I would assert that it is bad advice to post guidance that contradicts this.

 

[winston1]

The installation instructions for the UK - shown above - say that the fuse should be 3amp.
As this is a forum aimed at DIYers, I would assert that it is bad advice to post guidance that contradicts this.

But why should the UK require different protection to other parts of the EU? Typical example of MI being stupid.

 

[JohnW2]

The installation instructions for the UK - shown above - say that the fuse should be 3amp.
As this is a forum aimed at DIYers, I would assert that it is bad advice to post guidance that contradicts this.

The installation instructions would also appear to say that it must not be connected to a circuit protected by a SP MCB - which presumably means that it could/should/must not be used in hardly any domestic premises, doesn't it?

... and (I've just noticed), would not ...

Just put a 3A fuse in the plug and you are ready to plug it in.... Simples!

...also violate the requirement that it "must be connected directly to the mains" (as above) ??

Kind Regards, John

 

[bernardgreen]

But why should the UK require different protection to other parts of the EU?

Maybe because in the UK we have higher safety standards, We in the UK prefer the fuse / MCB to remove power before the cable gets warm due to a faulty appliance / wiring while those in the EU are happy for the cable to get hot before the over current protection removes power.

Typical example of MI being stupid

I think the manufacturer is aware that the UK system offers better methods of protection and takes advantage of that by specifying a 3 amp fuse in the supply.

 

[bernardgreen]

Another thing

The manufacturer states ""This is a Class Two Appliance and MUST NOT be Earthed""

Which means that a fault in the unit can result in exposed to touch metal becoming Live ( probably would require two faults if the double insulation is to be breached )

The exposed to touch metal is going to be pulled to some voltage by the capacitive coupling of wiring to case. High impedance coupling so insufficient current to do any harm to some one who touches the metal of the appliance but enough that some sensitive people will feel a tingle or mild "buzz" when they touch the appliance.

So what harm can come from earthing the appliance's exposed to touch metal work ? I am aware that if the person was holding a live bit of metal in one hand they could safely touch an un-earthed appliance with the other hand, but if that appliance's exposed to touch metal was earthed then they could received a severe, possibly fatal shock.

 

[Keitai]

Ok so called screwfix and girl said we cant just use a plug. She was reading off the script and doesn't understand anything. She asked someone else and they said it's better to be hardwired. But clearly they dont know anything. Last extractor was just a plug.

I looked in my kitchen and this thing under arrow (in photo)looks just like the double pole switched fuse spur outlet stated in instructions. It controls the socket for extractor, toaster and microwave ( i tested it.) It has a 13 amp fuse.

Does this mean it's ok to just put a plug with 3 amp fuse onto extractor into wall above stove?

 

[EFLImpudence]

Maybe because in the UK we have higher safety standards, We in the UK prefer the fuse / MCB to remove power before the cable gets warm due to a faulty appliance / wiring while those in the EU are happy for the cable to get hot before the over current protection removes power.

No, it is because the UK has 30/32A circuits necessitating extra safety methods which otherwise are unnecessary.

I think the manufacturer is aware that the UK system offers better methods of protection and takes advantage of that by specifying a 3 amp fuse in the supply.

I think it might be like JohnW2 who uses the smallest possible - because you can. It is more likely just what they write.

 

[SFK]

Keital
"Does this mean it's ok to just put a plug with 3 amp fuse onto extractor into wall above stove?"

Yes that is ok and will work perfectly.

It meets the instructed requirements of the fan (double pole switch, 13A fuse, double pole switch on removal of plug from socket, 3A fuse), and will be safe.
And matches with what EFLImpudence and Taylortwocities said earlier.

SFK

 

[EFLImpudence]

The manufacturer states ""This is a Class Two Appliance and MUST NOT be Earthed""
Which means that a fault in the unit can result in exposed to touch metal becoming Live ( probably would require two faults if the double insulation is to be breached )

No, it does not.
Class 2 appliances do not have "exposed-conductive-parts" in our electrical meaning.

The exposed to touch metal is going to be pulled to some voltage by the capacitive coupling of wiring to case. High impedance coupling so insufficient current to do any harm to some one who touches the metal of the appliance but enough that some sensitive people will feel a tingle or mild "buzz" when they touch the appliance.

So - it doesn't matter, then.

So what harm can come from earthing the appliance's exposed to touch metal work ? I am aware that if the person was holding a live bit of metal in one hand they could safely touch an un-earthed appliance with the other hand, but if that appliance's exposed to touch metal was earthed then they could received a severe, possibly fatal shock.

Well, there you go then. Plus the reverse - becoming live because of a fault elsewhere.

Earthing is not a good thing in itself. It is a necessary evil.

It would be better if nothing needed earthing - like Class 2 items don't.

 

[bernardgreen]

No, it is because the UK has 30/32A circuits necessitating extra safety methods which otherwise are unnecessary.

Having seen a table lamp cable almost melt ( table damaged ) before the protective device operated I feel the ability to put a 3 amp fuse in the circuit is a necessary "extra" safety method when the socket is protected by a 16 or 6 amp device in the consumer unit.