"Mike" wrote | > 130-01-01 Good workmanship and materials shall be used. | I'm afraid this is far too vague and open to interpretation.
See Stefek's reply.
| > 130-02-01 All equipment shall be ...installed .. so as to prevent | > danger as far as is reasonably practicable. | Again vague but see where you are going.
I think it's fairly clear that an installation (or its manner of installation) must be considered with overall safety in mind, not just electrical safety.
| > 314-01-01 Every installation shall be divided into circuits as | > necessary to: | > (i) avoid danger in the event of a fault, and (ii) facilitate safe | > operation, testing and maintenance. | Argument here could be whether an MCD or an RCD constitutes a circuit.
From this point of view, if the RCD trips then everything downstream of it is on the same circuit, even if there are MCB'd sub / branch circuits.
| > 314-01-02 A separate circuit shall be provided for each part of the | > installation which needs to be separately controlled for compliance | > with the Regulations *or otherwise* to prevent danger, so that such | > circuits remain energised in the event of failure of any other circuit | > of the installation, and *due account shall be taken of the consequences | > of the operation of any single protective device*. | Now this is far clearer. Though bear in mind it could be taken to mean you | need an individual RCB on every circuit.
I think it could, especially for a TT installation where the alternative is usually a 100mA RCD main switch, which would take out all the lighting circuits if there was a fault on one. On a commercial or high-risk installation it would be reasonable to specify RCBO on all circuits.
The Reg only requires account to be taken of the of the consequences of the operation of any single protective device, not the *liklihood* of its operation, however, and it should be that the 100mA RCD main switch is not subjected to nuisance tripping - such circuits should be on RCBOs or split-load with adequate discrimination.
On PME installations lighting circuits would not normally be RCD'd at all.
| > The above taken in conjunction with Peter Parry's comments on the number | > of deaths through falls possibly linked to sudden loss of light on staircases | > suggests to me that a whole-house RCD is not only in breach of the Regs, | > but incompetent verging on negligent (unless there are other provisions | > eg emergency lighting). | Can't agree with this. Didn't see the post you mean but every set of stairs | should have at least a torch at the top in case of powercuts. Far more | regular than a RCD tripping round here.
And once person A has taken the torch downstairs, what is person B to do?
Also, a torch does not address the problem of what happens when the lights go off whilst someone is mid-step on the staircase. The installation is to be installed "so as to prevent danger" and I don't think anyone would seriously suggest that a Design Certificate should be signed off 'provided a torch is kept at the top of the stairs'.
If frequent power cuts occur then emergency (and possibly standby) lighting should be installed as an integral part of the overall electrical installation.
Owain