Adding a light to a circuit with no earth

[Ian1981]

It mightn't be more dangerous, but it would still fail to meet the minimum safety standard for electrical installation work, i.e. BS7671.

Why? It's changing a pendant to 3 down lights.
Class 2 fittings hopefully.
Same as if you change a db and reconnect the lights.
If all class 2 you wouldn't rip the place apart installing a cpc unless agreed with customer

 

[Risteard]

Why? It's changing a pendant to 3 down lights.

Why would it fail to meet BS7671? Quite simply because it wouldn't comply with it.

 

[Ian1981]

Why would it fail to meet BS7671? Quite simply because it wouldn't comply with it.

By that logic a lighting circuit containing no cpc must not be re-energised when renewing a consumer unit even with class 2 fittings fitted and suitably labelled which is allowed by bs 7671

A cpc is required to connect exposed conductive parts to the MET so if a fault of negligible impedance between live and earth happens current will flow and disconnect the protective device,but tell me what exposed parts are there on a class 2 light?

 

[Midwest]

But the point is Ian, if you are installing new wiring, i.e. alteration or addition, then whatever you do must comply with current edition BS 7671.

If you are installing a new CU and connecting a lighting circuit without a cpc, you are not adding to etc, and 'conditions' apply, otherwise the circuit should not be connected (most guidance I've read, also recommends advising customer to rewire said circuit).

I have not read, or been informed by others, that it is compliance with BS 7671, to add new wiring to an existing circuit without a cpc.

 

[Risteard]

By that logic a lighting circuit containing no cpc must not be re-energised when renewing a consumer unit even with class 2 fittings fitted and suitably labelled which is allowed by bs 7671

Firstly replacing a distribution board is quite different as you are not altering the existing circuit (leaving aside the protective device for now). So you are only required to verify your installation work (namely the replacement distribution board) - so you would ensure that the protective devices will operate in the time required. It doesn't mean that you are taking responsibility for installation methods; core colours etc.

Secondly, you state "with Class II fittings fitted and suitably labelled which is allowed bs BS7671". Can you quote where BS7671 suggests that this is acceptable, or prescribes any label for this eventuality? I can assure you that it is not contained within BS7671.

 

[Ian1981]

Available from Niceic direct
Bs 7671 does not go into long explanations of rules and regulations.
It's a set of regulations hence why we have guides and guidance notes to break the information down in to chunks

Firstly replacing a distribution board is quite different as you are not altering the existing circuit (leaving aside the protective device for now). So you are only required to verify your installation work (namely the replacement distribution board) - so you would ensure that the protective devices will operate in the time required. It doesn't mean that you are taking responsibility for installation methods; core colours etc.

Secondly, you state "with Class II fittings fitted and suitably labelled which is allowed bs BS7671". Can you quote where BS7671 suggests that this is acceptable, or prescribes any label for this eventuality? I can assure you that it is not contained within BS7671.

 

[Midwest]

Whilst researching this topic, I found reg 412.2.3.2, which I'll let you chaps read and explain, cos my heads hurting now.

On this point, would running a cable from a 12v dc transformer, to a remote luminaire require a cpc?

 

[Risteard]

I am aware that such labels are for sale - my point is that they have no basis within BS7671.

 

[Ian1981]

i would say not every label available is written in the realm of bs 7671 on display as it where

 

[Ian1981]

Whilst researching this topic, I found reg 412.2.3.2, which I'll let you chaps read and explain, cos my heads hurting now.

On this point, would running a cable from a 12v dc transformer, to a remote luminaire require a cpc?

Well I'd say if it's selv then the cpc is required to be not connected to the primary side of the source

 

[Midwest]

Well I'd say if it's selv then the cpc is required to be not connected to the primary side of the source

Just a thought Is that a double negative thing?

 

[Midwest]

I am aware that such labels are for sale - my point is that they have no basis within BS7671.

That's not a reason, not to have them. Anything that makes things which are unclear more clear, must be grasped,

 

[Wilko]

My thought is any new cable must have a cpc, and the cpc must be tested and confirmed for connectivity to the MET. And these are new cables to the new downlight positions...

 

[Andy78]

That's not a reason, not to have them. Anything that makes things which are unclear more clear, must be grasped,

They certainly don't not make things less unclear than they wouldn't have not been if they weren't there at all.

 

[robo83]

Thanks for all the replies.

 

[Midwest]

They certainly don't not make things less unclear than they wouldn't have not been if they weren't there at all.

Arrgh you missed the point;

 

[Midwest]

On this point, would running a cable from a 12v dc transformer, to a remote luminaire require a cpc?

Any more technical points on the above?

 

[Risteard]

That's not a reason, not to have them. Anything that makes things which are unclear more clear, must be grasped,

There's no reason to prescribe a label for a prohibited arrangement though.