Code C1 = dangerous which is near enough, however code C2 = potentially dangerous and lets face it 230 volt is always potentially dangerous. The problem is there is no standard to work to, we have regulations which state the date after which a design must follow them, but it is the design date, not the commissioning date, so a new property can have an installation which when first used does not comply with current regulations.
However we don't go into a property armed with a bookcase full of regulations so we can select the correct one, the new law says BS7671:2018 but BS7671:2018 gives the design date at which it needs to be followed, so in essence it redirects one to an earlier version.
But again BS7671 is not retrospective, but HSE laws and CENELEC harmonization documents are, so although it may comply with the wiring regulations it may not be legal to use, the only way we can be sure it is legal is to use the current regulations. However this means a new building could fail.
The IET felt that having a code to say it does not comply with current regulations if designed today was unhelpful, so code 4 which was just that was removed, so we have 7 codes:-
- C1 = Danger Present (FAIL)
- C2 = Potentially Dangerous (FAIL)
- C3 = Improvement Recommended.
- FI = Further Investigation Required (FAIL)
- N/V = Not Verified (Unable to verify)
- N/A = Not Applicable.
- LIM = Limitation (Not tested or inspected)
Some are nearly the same LIM and FI for example, we would give a FI if a room was locked, but if for example the garage was not rented with the house, that could get a LIM.
However the demarcation between code C2 and C3 is rather vague, as long as the inspector lists the problems he has done his job, so one inspector may give a C2 for no RCD and another a C3. There is a problem with bathrooms, in 2008 the edition of BS7671 released allowed items in bathrooms not to be bonded if it was RCD protected with a 30 mA RCD, so if both bonding and RCD missing then clearly a code C2.
Through the years there have been changes, my parents house built 1954 had wooden back boxes behind the light switches, and bakelite switches, of a design where there was no metal that could be touched that could be earthed, but in 1966 the rules changed and earths had to be run to all lights except for the actual pendent. So all GU10 lamps must have an earth available even if not used.
So the big question is how far back can one go? At one time we had knife switches with exposed live parts, that is clearly not acceptable today.
So you have a law which needs case law to clarify the finer points, but who is going to allow themselves to be taken to court rather than spend £500 on some safety items? So it is unlikely there will be court case to clarify the new law. So each inspector has his own idea as to where the demarcation line should lie.
So back to "Potentially Dangerous" if HSE laws and CENELEC harmonization documents say it is not permitted, that does not mean it is "Potentially Dangerous" the inspector can give "Improvement Recommended" and he has not broken any rule, he has to do what it says on the can, he has to decide if it is "Potentially Dangerous".
So a sound house, with rental rules which do not permit and drilling of the walls, and there are no sockets likely to be used outside, the inspector could well say RCD not required, but a house with leaking roof, and a large garden with a pond in it with fountains etc, he would likely say hang on for this house we really need RCD protection to be safe.
Same with metal consumer units, a plastic consumer unit in the kitchen and multiple escape routes no real problem, the same consumer unit under wooden stairs which are the only escape route, and no really does need to be metal.
But this means the inspector needs to use his skill to judge what passes and what fails, easier to just fail anything without RCD protection. But how far does one go? Does one say an electric car could be parked there and so we want not only RCD protection but RCD protection using a type B RCD and since a TN-C-S supply a voltage detector to auto disconnect supply if the voltage is not 207 to 253 volt, I think most would say that is going OTT, but could not say wrong.
So really the law is an ass, it should have been like a car MOT with in the main a good manual to guide the inspectors, most seem to think Electrical Safety First Best Practice Guide No. 4 (Issue 5)
Electrical installation condition reporting: Classification Codes for domestic and similar electrical installations.
is the best option when deciding what codes to issue, not perfect, but it is reasonable. In this guide we have
this picture of a fuse box without any RCD protection and made of bakelite so not really fire resistant and it says it can continue to provide satisfactory service, so it would seem following best practice lack of RCD is not a fail.
However my own house the old Wylex fuse box has been removed and replaced with a metal consumer unit all RCBO with a SPD. And I would recommend today everyone should have RCD protection and that since my CU is not in the main house, I don't want to be forced to go outside and down a set of steps in the snow because the RCD has tripped, and one RCBO's are less likely to trip, and two if one does trip I have only lost that circuit. As to the SPD not sure if really needed, but I have heard complaints about LED bulbs failing, and as yet in this house not had to replace any LED lights, not saying that is due to the SPD, but it may explain why I have not lost a light and others have.
To my mind to find some one to change a fuse box for a consumer unit within 28 days is a tall order, it took me 4 months to get around to changing it, it is one of those jobs you do when freezer is empty. Or at least not much in it. If the bathroom has missing bonding then yes it is a must that either bonding installed or RCD fitted, but unless that is the case, then really only a code C3.