Smoke/heat detectors again

johnbuckley · 24 Aug 2021

I know this has been done to death but I have read so much conflicting info that I just have to ask, so I apologise for that.

I have fitted 3 smoke detectors and one heat detector which I have interlinked and run the cable (1.5mm 3 core and interlink) to the consumer unit ready for connection.

The consumer unit is of the older type with Vynckier mcb's, fitted 1993 according to a sticker on it.
My question is twofold.
1. Am I legally allowed to make the connection. (I'm not a spark clearly)
2. From what I have gathered it is recommended to be powered from the downstairs lighting circuit which is on a 6 amp mcb. Can the cable connect directly to the mcb with the lighting cable or does it need to come from the lighting mcb to a switch which I assume to be an FCU.
Would be much easier to just fit another mcb just for the detectors although that doesn't seem to be recommended.
Thank you in advance.

ericmark · 24 Aug 2021

It is more to do with common sense, if on their own circuit, would you know if the circuit failed? In England and Wales what your allowed to do without notifying is not the same, and you can do any work, but the cost of notifying makes some work uneconomic to do as DIY.

The Part P laws are freely available, read it yourself, it is more down to English comprehension than electrical. And you will see arguments galore as to what a new circuit is. Good example is the fused connection unit (FCU) if you fit one on a ring final then you could say that's a new circuit, however the name ring final means it is the final circuit, so you can't have a circuit after it, but a circuit is defined as "An assembly of electrical equipment supplied from the same origin and protected against over current by the same protective device(s)." it is generally considered a FCU does not generate a new circuit, but it is not a degree in electrical engineering one needs, but a degree in English.

And of course in Wales it all has to be also written in Welsh, which causes a problem, as the laws refer to BS 7671 which is only available in English, so not law. In fact it actually says

The Regulations are non-statutory. They may, however, be used in a court of law in evidence to claim compliance with a statutory requirement. The relevant statutory provisions are listed in Appendix 2 and include Acts of Parliament and Regulations made thereunder. In some cases statutory Regulations may be accompanied by Codes of Practice approved under Section 16 of the Health and Safety at Work etc. Act 1974. The legal status of these Codes is explained in Section 17 of the 1974 Act.
For a supply given in accordance with the Electricity Safety, Quality and Continuity Regulations 2002, it shall be deemed that the connection with Earth of the neutral of the supply is permanent. Outside England, Scotland and Wales, confirmation shall be sought from the distributor that the supply conforms to requirements corresponding to those of the Electricity Safety, Quality and Continuity Regulations 2002, in this respect. Where the ESQCR do not apply, equipment for isolation and switching shall be selected accordingly as specified in Chapter 53.

If you can work that all out your better than me.

Taylortwocities · 24 Aug 2021

If you fit a new MCB then that will constitute a new circuit. New circuits are notifiable, you’d need a registered electrician to do this.

If you connect to the existing B6 MCB, this is an addition to an existing circuit and (It depends where you live) at least in England it’s not notifiable.

I note that you have

johnbuckley said:
run the cable (1.5mm 3 core and interlink) to the consumer unit ready for connection.

You only need live, neutral and earth to the first alarm. So three core plus earth is not needed. As you have run the cable already, put the spare core in the earth bar and connect it to earth at the first alarm.

JohnD · 24 Aug 2021

ericmark said:
The Part P laws are freely available, read it yourself, it is more down to English comprehension than electrical.

The Requirements section of Part P is 28 words

(In England.)

(I don't know the number in Welsh)

johnbuckley · 24 Aug 2021

ericmark said:
It is more to do with common sense, if on their own circuit, would you know if the circuit failed? In England and Wales what your allowed to do without notifying is not the same, and you can do any work, but the cost of notifying makes some work uneconomic to do as DIY.

The Part P laws are freely available, read it yourself, it is more down to English comprehension than electrical. And you will see arguments galore as to what a new circuit is. Good example is the fused connection unit (FCU) if you fit one on a ring final then you could say that's a new circuit, however the name ring final means it is the final circuit, so you can't have a circuit after it, but a circuit is defined as "An assembly of electrical equipment supplied from the same origin and protected against over current by the same protective device(s)." it is generally considered a FCU does not generate a new circuit, but it is not a degree in electrical engineering one needs, but a degree in English.

And of course in Wales it all has to be also written in Welsh, which causes a problem, as the laws refer to BS 7671 which is only available in English, so not law. In fact it actually says
If you can work that all out your better than me.

Well I'm certainly not better than you but I take from all that, I won't be fitting a new mcb and so avoid the 'new circuit' malarkey.
Thanks for replying

ericmark · 24 Aug 2021

Taylortwocities said:
If you fit a new MCB then that will constitute a new circuit. New circuits are notifiable, you’d need a registered electrician to do this.

Or pay a silly amount of money to the local authority building control, in Wales it is £100 plus vat, you can DIY, but it is likely more expensive than using a scheme member electrician. Not a registered electrician, I am a registered electrician but not a scheme member.

ericmark · 24 Aug 2021

JohnD said:
The Requirements section of Part P is 28 words

(In England.)

(I don't know the number in Welsh)

dau ddeg wyth

Taylortwocities · 24 Aug 2021

JohnD said:
(I don't know the number in Welsh)

dau ddeg wyth
Simples!

Meerkat

Taylortwocities
11 Dec 2009
53

johnbuckley · 24 Aug 2021

Taylortwocities said:
If you fit a new MCB then that will constitute a new circuit. New circuits are notifiable, you’d need a registered electrician to do this.

If you connect to the existing B6 MCB, this is an addition to an existing circuit and (It depends where you live) at least in England it’s not notifiable.

I note that you have

You only need live, neutral and earth to the first alarm. So three core plus earth is not needed. As you have run the cable already, put the spare core in the earth bar and connect it to earth at the first alarm.

Thanks for that.
Yes I realised I only needed to run 3 core T&E to the first detector after I'd done it, I can still change it as the first detector is easy to access.
So directly into the lighting mcb it is.
Thanks for replying.

Taylortwocities · 24 Aug 2021

May as well use the cable if it’s there.

diynot

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Smoke/heat detectors again

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