Booster Box connected to electrical supply

[winston1]

Couldn't see any mention of an FCU only a fuse, even then it said not required if off a 6 amp lighting circuit.

Remember we don't have to follow the manufacturers instructions, which are guidance anyway, especially if they are wrong.

 

[securespark]

Manrose instructions picture a 3A double pole FCU.

Greenwood instructions say no fuse required if 6A, meaning if it is higher, you need a fuse. They also picture a DP switch.

You are being selectively blind now!

Saying the manufacturers are wrong is just silly.

 

[JohnW2]

Does BS7671 say a FCU cannot be used on a lighting circuit?

Indeed it doesn't! Another thing worth considering is that nor does BS7671 say that (new) FCUs have to be RCD protected, whereas it does say that about (new) sockets. It is not unknown for lighting circuits (even all circuits!) not to be RCD-protected and, in that situation, hard-wring to a new FCU would be compliant, whereas installing a new socket probably wouldn't be.

Kind Regards, John

 

[PrenticeBoyofDerry]

The fact that you come across something wrong all the time does not make it right.

The fact is, that it is not wrong!
Whether they are needed or not will depend on other variables and situations!
Not following MIs, would again depend on the quality of the information within them and that should be logically assessed.

 

[PrenticeBoyofDerry]

Indeed it doesn't! Another thing worth considering is that nor does BS7671 say that (new) FCUs have to be RCD protected, whereas it does say that about (new) sockets. It is not unknown for lighting circuits (even all circuits!) not to be RCD-protected and, in that situation, hard-wring to a new FCU would be compliant, whereas installing a new socket probably wouldn't be.

Indeed. So installing a new socket outlet, opposed to a FCU, could incorporate other additional protective measure, if they do not already exist!

 

[JohnW2]

Indeed. So installing a new socket outlet, opposed to a FCU, could incorporate other additional protective measure, if they do not already exist!

Sure, but, as I said, if one installed an FCU and hard-wired to it (rather than having a socket), there probably would not be a regulatory requirement for RCD protection at all.

In terms of what you suggest, those who think more about common sense than about regulations may question the 'value' of RCD-protecting a socket in a loft that is powering an aerial amplifier!

Kind Regards, John

 

[EFLImpudence]

What's a lighting circuit?

 

[JohnW2]

What's a lighting circuit?

You tell me (regs-wise)! I suppose the common sense meaning is a circuit which primarily or predominantly serves lights - although, as you point out, it could be a 'lighting + booster', 'lighting + fan(s)', 'lighting + fan + shaver' circuit or whatever. Again in terms of common sense, it's not a circuit designed to supply 'general purpose' (aka '13A') socket outlets.

Kind Regards, John

 

[bernardgreen]

The isolation between mains voltage and the aerial cable could fail ( dampness in a cold loft ) and thus the aerial screeen and signal lead could be pulled towards mains voltage.

A shock risk not only to someone on the roof but also to people touching the screen connection at the back of the TV. The screen is often connected only via a capacitor to the 0v / ground inside the TV. So RCD protection could be advantagous

 

[winston1]

The fact is, that it is not wrong!
Whether they are needed or not will depend on other variables and situations!
Not following MIs, would again depend on the quality of the information within them and that should be logically assessed.

Since harmonisation such products should be able to be used anywhere in the EU. Many EU countries put lighting and socket circuits on 16amp MCBs. Also FCUs are unavailable and non compliant. So to ask for a FCU is wrong. The cable should be suitable for a 16amp circuit as any upstream fuse/MCB is there purely for the protection of the cable. If they have used smaller cable they are also wrong. For protection of the booster, fan, or whatever internal fusing or other protection should be provided.

 

[PrenticeBoyofDerry]

It is not wrong though, there is nothing excluding FCU from being on 6Amp, 10amp or 16Amp circuits.

 

[EFLImpudence]

It's not 'wrong' as such but I agree with Winston on this one in that it should never be needed.

The most obvious examples -

Boilers, always(?) on a 3A FCU, boiler has internal fuses so is it really necessary?
Extractors, nearly always argued against and put down to poor manufacture but is it?
Cooker hoods, the same?

 

[JohnW2]

It's not 'wrong' as such but I agree with Winston on this one in that it should never be needed.

I think that many of us probably also agree.

Boilers, always(?) on a 3A FCU, boiler has internal fuses so is it really necessary?

I don't think it particularly alters my view, but, for what it's worth, I think that probably depends upon the age of the boiler. To the best of my knowledge, mine contains no fuses.

Kind Regards, John

 

[EFLImpudence]

Has your boiler anything which may require protection less than the circuit OPD?

 

[JohnW2]

Has your boiler anything which may require protection less than the circuit OPD?

I'm not sure that my truthful answer to that question will be of much use to this discussion, since my CH system is fed from a 32A utility room sockets circuit. As such, quite apart from the wiring (and whatever) within the boiler (and associated items), even the flex feeding it would probably not be adequately protected by the 32A MCB, given that one probably can't reasonably assume that 'overload is impossible', since there are multiple motors involved (pumps, MVs etc.). For that reason, the CH system is supplied via a 3A fuse (actually in a plug, not FCU, to facilitate plugging into the generator supply, rather than using a c/o switch).

If it were a 6A or 10A (or probably even 16A) circuit, I would probably not feel the need for any 'down-fusing' (although, doing things as I have done, there would inevitably be a fuse in the plug {assuming I used a BS1363 one}, which might as well be 3A or 5A one).

Kind Regards, John