fcu spur off lighting circuit

[jg321]

FCU's are not required or used on lighting circuits.

Serious question. What about the following scenario:

10A lighting circuit (which I had in my old flat).
Appliance with 0.75mm flex that I want to connect to it.

Would a fuse be required in this case?

 

[JohnW2]

They could include a bit to educate the public and use 12V and 230V.

Well, in my opinion, they probably should stick with just 12V and 230V and not introduce potential confusion by talking about "Low", "Extra Low" or any other type of voltage.

Given that the wide range of possible voltages represented by ELV and LV, the terms are meaningless unless qualified by the actual voltage - and if one specifies the actual voltage, then descriptors such as LV and ELV become totally irrelevant! ... hence 'education' should not really be required.

Do you think they don't know? If not, does that bode well for the rest of the instructions?

Who knows? They might 'not know' - but they might 'know', but want to communicate effectively with the vast majority of their customers.

Kind Regards, John

 

[EFLImpudence]

Serious question. What about the following scenario:

10A lighting circuit (which I had in my old flat).
Appliance with 0.75mm flex that I want to connect to it.

Would a fuse be required in this case?

No.

Your kettle likely has 0.75mm² flex.

 

[JohnW2]

10A lighting circuit (which I had in my old flat). Appliance with 0.75mm flex that I want to connect to it. Would a fuse be required in this case?

You could equally ask him about an 'appliance' (perhaps a light) which had 0.5mm² flex on a 6A lighting circuit. He might well to try to argue that a 3A fuse "would not discriminate from" a 6A MCB, but try telling BS7671 that that is an acceptable reason for protecting a cable with a CCC of 3A with a 6A OPD

Kind Regards, John

 

[jg321]

Your kettle likely has 0.75mm² flex.

I'll get it wired into my lighting circuit then!

 

[jg321]

You could equally ask him about an 'appliance' (perhaps a light) which had 0.5mm² flex on a 6A lighting circuit. He might well to try to argue that a 3A fuse "would not discriminate from" a 6A MCB, but try telling BS7671 that that is an acceptable reason for protecting a cable with a CCC of 3A with a 6A OPD

Indeed. It was the 10A lighting circuits that I used to have in my old flat that made me wonder if Winston would think the same in this case.

I could have probably worded the above better. It's very hot in Manchester currently.

 

[EFLImpudence]

I'll get it wired into my lighting circuit then!

That's not the point; it will have a(n unnecessary) 13A fuse on a 32A circuit.

 

[jg321]

That's not the point; it will have a(n unnecessary) 13A fuse on a 32A circuit.

Wait, so we're now saying that fuses in plugs are also not required?

 

[JohnW2]

Indeed. It was the 10A lighting circuits that I used to have in my old flat that made me wonder if Winston would think the same in this case.

Regardless of his views about (non) discrimination, I really don't see how he could justify protecting 0.75mm² cable with a 10A OPD or 0.5mm² cable with a 6A OPD ... but who can read his mind?!

Kind Regards, John

 

[EFLImpudence]

Wait, so we're now saying that fuses in plugs are also not required?

Well - they are required in Britain but not electrically necessary for a kettle nor lots of other appliances.

 

[EFLImpudence]

Regardless of his views about (non) discrimination, I really don't see how he could justify protecting 0.75mm² cable with a 10A OPD or 0.5mm² cable with a 6A OPD ... but who can read his mind?!

433.

 

[JohnW2]

433.

Yes (you presumably mean 433.3), but his argument is that a fuse is required in order to protect the cable. You are now (presumably) suggesting (correctly in many cases) that a fuse might not be required even for that!

I think that one thing one has to bear in mind that, at least in the case of 'fixed wiring', one cannot necessarily be certain of what it might be used for in the future, so one perhaps has to be a little careful in deciding that overload protection may be omitted on the basis of the nature of the current (I mean 'now', not electrical current!) load.

Kind Regards, John

 

[winston1]

You could equally ask him about an 'appliance' (perhaps a light) which had 0.5mm² flex on a 6A lighting circuit. He might well to try to argue that a 3A fuse "would not discriminate from" a 6A MCB, but try telling BS7671 that that is an acceptable reason for protecting a cable with a CCC of 3A with a 6A OPD

Kind Regards, John

That same appliance in Europe would plug into a circuit with a 16 A OPD. They don't seem to have problems there.

 

[winston1]

Well - they are required in Britain but not electrically necessary for a kettle nor lots of other appliances.

Only if you use one particular type of plug (with rectangular pins, you know the one I mean). If you use round pin plugs, which is allowed, fuses in them are not required.

 

[JohnW2]

That same appliance in Europe would plug into a circuit with a 16 A OPD. They don't seem to have problems there.

Maybe not, so are you invoking 433.3 in the same way that EFLI seemingly was?

If not (i.e. if you believe that the cable requires protection against overload) then, no matter what country you're in, you cannot provide that protection for 0.5mm², 0.75mm², 1.0mm² or 1.25mm² cables with a 16A OPD.

Kind Regards, John