How will it past

[samil]

Dear All

I am an Electrical inspector and tester.
If lighting circuit has got cpc cable from distribution board to the light itself
but it is not closed circuit.
another meaning when I connected phase to cpc from lights and measure from distribution board it looks open circuit
how can make it past from inspection.
I notice this when I am measuring R1 + R2

Many Thanks

samil

[barry bartfast]

Looks like you have an open circuit cpc, perhaps the cpc is not prperly connected at one of the light fittings.

[solo3uk]

I know it sounds silly but it is an oversight that can happen to anybody. When you measure R1+R2, do you turn the light switch on?. You might have phase o/c due to the switch not being on.

I would measure R1 first and then R2 and find out which cable is o/c.

good luck

[samil]

Thank you very much for your answers.
I tried switch on/off as well. but still it was showing open circuit.
my question is; can this circuit passes or fails?
Do we really need cpc for lightings?
many thanks

samil

[solo3uk]

Samil your case is a defenite FAIL. IEE Reg 471-08-08 & 544-01-01 apply in this case. If you find there isn`t a CPC (circuit protective conductor) you must give a choice to the customer in order to pass the installation. Either rewire the circuit completely with a cable incorporating a CPC or run a separate CPC from the MET (main earthing teriminal) on its own to the equipment.

The need for the CPC is only required in Class I equipment, like metal clad lights, metal switchplates and socket plates or even plastic ones if mounted on a metal box due to the exposed screws holding the plate, etc,. Previous to 1966 there wasn`t a reg requiring earthing of lighting circuits.

[Jimbo]

Solo 3 Uk, If there was no CPC it cannot be anything more than not to current regs, no reg can be applied retrospectively sure you can advise the customer but it cannot be anything more than advice. Regards Jimbo

[samil]

Dear Jimbo and solo 3 uk and other members
Thank you very much for the reply.
Am I right to say that
I have 2 option for the client
1)add new cpc or find fault with the existing cpc or
2)change all metal cover and any other metal items connected to the lights and replace with non-metalic cover and body

Many Thanks

samil

[solo3uk]

We must be clear in this issue. There are two aspects to this problem here. First of all either Samil is inspecting and testing the installation to issue a certificate or he is going to carry out alterations or additions.

If he is just testing the installation he can`t pass it as safe if he finds the lights circuits and equipment are not earthed, He can`t leave class I equipment unearthed and issue a test certificate. If all the equipment in the circuit is class II and he replaces like for like, it might be ok, but I`m not sure. Like for like replacement is outside the scope of BS7671 because it doesn`t constitute an addition or alteration. However if the circuit has class I equipment and he replaces it with class II in order not to earth the circuit then he has to provide a CPC to the whole circuit in case later on somebody else should replace that equipment again to class I, he is not replacing like for like.

BS7671 states that upon finding that an earthing arrangement does not meet the requirements of BS7671 the competent person should notify the customer of this in writing and without delay giving a recommendation for remedial action requiring urgent attention, and he can`t carry out any addition or alteration till that is done.

BS7671 is also clear as far as additions and alterations are concerned. Alterations and additions, even a minor one, must not be made to an existing installation unless the earthing and bonding arrangements are adequate. The earthing and bonding arrangements will have to be upgraded to the current standard before an alteration or addition can be made. So if Samil is going to do an alteration or addition to that circuit he`ll have to earth it.

Regs are not retrospective as Jimbo says as long as there is no safety issue involved to provide a certificate or no alteration or addition is carried out.

I`d be very grateful if somebody could sort out the conumdrum of an unearthed light circuit supplying only class II equipment.

[samil]

Thank you very much "solo3uk" for your long detailed explanation. I understood that this issue a bit unclear in the regs. but from your explanation I understood that the circuit should be failed and even replacing with class II equipment is not good enough, just in case some body in the future change Class II to Class I equipment again.
I was going to issue an Inspection & Testing Report.
Many Thanks

regards

samil

[solo3uk]

Glad to be of some help Samil, the only way to understand these regs is by dialogue as there seems not to be fast rules about them.
many regards