RCD Protection For Old Installations

“Sorry, just the abbreviation got me confused, got those! ” 

I hate abbreviations because they can confuse .

OK a few very common ones I can live with.

OK a few more specific ones related to our trade might be in order too.

But other than that if abbreviations are to be used then their first use in any topic should be spelt out.

Whilst we`re on it then what is meant by i.a.w?

i thought that the regs are not retrospective, so it should be listed as recommendations to comply with current regs, but should be inspected under the regs that were current when the installation was completed. for example, the cable colours have changed, but would that be a reason to rewire??   

It's never been the case that you apply the regs that were in force at the time of install. Otherwise you would have to say that an old installation untouched since the 1920s is perfectly fine.

An EICR is supposed to list in what ways the installation isn't up to current regs. The only debate is what coding to give each compliance - chiefly whether it's the C3 “not current, but don't worry too much”, or a C2, which is a fail and in various situations like rented accommodation, may impose financial burdens on the landlord and inconvenience on the tenants.

grubbym: 
 

i thought that the regs are not retrospective, so it should be listed as recommendations to comply with current regs, but should be inspected under the regs that were current when the installation was completed. . . 

There are some who believe this, but it is very tenuous. Since the introduction of the “BS7671” title, the previous version of the standard is “withdrawn”. That effectively means it is “for information only”. I am not quite sure how people justify carrying out an inspection and test to a withdrawn standard, apart from the fact that it may be more likely to give the person wanting the test the result they want. 
 

Regards,

Alan. 

If you think 314.1 disallows a single RCD for an installation you should look carefully. Why do you suspect “excessive protective conductor currents not due to a fault” in a domestic installation 314.1 (iv)?  The usual excuse of "inconvenience" does not match that does it? Installations do not have this problem in most cases, the PE current in mine is less than 1 mA and I have quite a lot of electronics. I would also like to point out that if you can get inside the CU you can add an external RCD, the tails MUST be accessible, although this may require a degree of skill.

If the landlord is prepared to pay for you to fit a new CU and correct all discrepancies from BS7671 blue copy, then fine, but many may not. Then you can issue a new EIC, but surprisingly few actually do this correctly. There are NO C3 or whatever on a new EIC. You will note that the definition of installation is the whole system, writing “New CU” is in my view totally unsatisfactory. 

Electrical Installation: An assembly of associated electrical equipment having co-ordinated characteristics to fulfill specific purposes.

In other words, the cables, accessories, and everything else to provide electrical services in the property.

ebee: 
Whilst we`re on it then what is meant by i.a.w?

i.a.w. = in accordance with

For a lot of installations it is actually possible to get change out of a hundred quid for an all RCBO consumer unit, compared to buying an enclosure and RCD to tart up an old fuse board it a much better deal.

Split consumer units can be bought for less.

Is long as your happy that you have met the first part of 314.1 (avoid danger and minimise inconvenience in the event of a fault) then fit a single up front 30mA RCD. Personally I won’t for obvious reasons. 

I did not see any supplementary bonding there. Which makes it C2 in this case. 

Not necessarily - to prove non-compliance you need to take measurements between exposed-conductive-parts/c.p.c.s and/or extreaneous-conductive-parts and compare the results with the calculation in reg 415.2.2. As I mentioned earlier, in a small flat with the MET comparitively close to the bathroom it may be entirely possible for the c.p.c.s and main bonding to provide the required performance without any additional supplementary bonding conductors as such.

Just be careful with your consideration of which device's Ia you use.

   - Andy.

If the landlord is prepared to pay for you to fit a new CU and correct all discrepancies from BS7671 blue copy, then fine, but many may not. Then you can issue a new EIC, but surprisingly few actually do this correctly. There are NO C3 or whatever on a new EIC. You will note that the definition of installation is the whole system, writing “New CU” is in my view totally unsatisfactory. 

Eh? Surely it's perfectly correct to issue an EIC for just a CU replacement (or any other work beyond simple changes to existing circuits, where a minor works cert may be used) - what other BS 7671 cerification option is there? Nothing really suggests that an EIC always covers an entire installation - the presence of the ‘Extent of installation covered by this certificate’ makes it pretty obvious.  Of course there will be no C3s on the new EIC - the entire concept of reporting codes only applies to reports, not certificates. But it should be pretty obvious given an EICR with codes all over the installation and a new EIC for the replacement CU only that some codes may remain.

Likewise an EIC cannot cover existing part of an installation in addition to the new work - we can only issue certificates for work we've done. Anything else can only be a report. Unless the only option is a complete replacement of the entire installation every time … but I'm sure you weren't suggesting that.

   - Andy.