Inspection recommends new CU....

[EFLImpudence]

It IS acceptable IF your supply is TT (ground rod).

If new, your installation would have 30mA protection in the CU so the 100mA would not be necessary.

If it is a mistake then replace with 30mA.

You do not HAVE to update the installation to modern requirements.
It is up to you.

 

[JohnW2]

One more question please....was there a time when a 100mA RCD WAS acceptable?

AS EFLI said and implied, there are two reasons for having an RCD...

(1) if you have a 'TT' earthing system (i.e. a local earth rod, rather than an earth connection provided by the electricity supplier), then you must have an RCD to provide acceptable 'fault protection' for your installation - i.e. to ensure that the electricity gets disconnected if a 'short to earth' arises anywhere in the installation (e.g. from a toaster element to its casing). A 100 mA RCD always has been (and still is) acceptable for that purpose.

(2) RCDs are increasingly seen as a way of protecting people from fatal electric shocks, and that is the basis of the requirements of current regulations. Electric currents through human beings become much more likley to prove fatal if they rise appreciably above 30mA. To provide such protection of humans therefore requires an RCD rated at 30 mA (or less).

Hope that helps.

Kind Regards, John

 

[JohnW2]

If it is a mistake then replace with 30mA. You do not HAVE to update the installation to modern requirements. It is up to you.

As I have just written, would everyone necessarily see it that way?

As you say, there is no compulsion to update an installation to comply with current regs - so there would theoretically not be any problem (from that point of view) with just leaving things as they are.

However, if one decides to add 30 mA RCD protection to an installation which didn't previously have any (which could be regarded as 'new work'?), is it acceptable to install a single, installation-wide, 30 mA RCD?

Looked at another way, what if there were no RCD at all at present, particularly if it were a TN installation? Would you then regard it as acceptable, in 2014, to install a single, installation-wide 30mA RCD?

Kind Regards, John

 

[EFLImpudence]

I did not see your post until after I wrote mine, however:

As I have just written, would everyone necessarily see it that way?

Probably not.

As you say, there is no compulsion to update an installation to comply with current regs - so there would theoretically not be any problem (from that point of view) with just leaving things as they are.

True, but if it has been installed for personal protection (not TT) then it is a mistake which has been noted therefore, I suppose, it should be rectified.

However, if one decides to add 30 mA RCD protection to an installation which didn't previously have any (which could be regarded as 'new work'?), is it acceptable to install a single, installation-wide, 30 mA RCD?

It depends. It would be electrically safer. Is an 'unacceptable' method wrong if it makes it safer?
Although I doubt anyone would request such a thing, they would be content as it is.
If so, you are apparently agreeing with the inspector in that a new CU must be the only solution.

Looked at another way, what if there were no RCD at all at present, particularly if it were a TN installation? Would you then regard it as acceptable, in 2014, to install a single, installation-wide 30mA RCD

(Isn't that the same way?)
It would, as I said, be up to the owner.
Would an electrician actually refuse if that was what the owner wanted?

 

[mfarrow]

I did not see your post until after I wrote mine, however:

As I have just written, would everyone necessarily see it that way?

Probably not.

ESC would be a good start. They would not see it as safe if you are (or are in danger of) using the equipment outdoors. I would definitely upgrade in this case.

 

[JohnW2]

As you say, there is no compulsion to update an installation to comply with current regs - so there would theoretically not be any problem (from that point of view) with just leaving things as they are.

True, but if it has been installed for personal protection (not TT) then it is a mistake which has been noted therefore, I suppose, it should be rectified.

It would often be very difficult (other than in a relatively new installation which has 'obviously' always been TN) to be sure of 'why' it had been installed, wouldn't it?

However, if one decides to add 30 mA RCD protection to an installation which didn't previously have any (which could be regarded as 'new work'?), is it acceptable to install a single, installation-wide, 30 mA RCD?

It depends. It would be electrically safer. Is an 'unacceptable' method wrong if it makes it safer?

I'm not really talking about right and wrong, and we are agreed that it would be safer. Rather, I'm talking about the bureaucracy of whether an electrician should introduce new elements into an installation which are not compliant with current regs and, in particular, if they can/should then provide a certificate saying that it is compliant.

As you know, I often had this argument with BAS about 'pragmatism'. As far as I am concerned, anything which makes an installation safer, or which makes life safer for a DIYer, is 'better than nothing', even if non-ideal and/or non-compliant with regs - but I'm not sure that officialdom (or BAS!) sees things like that.

Although I doubt anyone would request such a thing, they would be content as it is. ... If so, you are apparently agreeing with the inspector in that a new CU must be the only solution. It would, as I said, be up to the owner. Would an electrician actually refuse if that was what the owner wanted?

As above, as far as I am concerned, personally, anything which improved safety would be worthwhile (and I would also respect the houseowner's wish to have nothing changed, if I were happy that they understood the risk). However, as above, that's rather different from the question of what an electrician can/should do.

If a customer who had an ancient installation/CU (with no RCD protection at all) asked you to install a new CU, but insisted that it should be one which had a single, installation-wide, RCD, would you take the job and, if so, what would you do about the certificate?

Kind Regards, John

 

[EFLImpudence]

If a customer who had an ancient installation/CU (with no RCD protection at all) asked you to install a new CU, but insisted that it should be one which had a single, installation-wide, RCD, would you take the job and, if so, what would you do about the certificate?

No, but that's not the same plus: Why would they?
A separate RCBO for the lights would satisfy the regulations in a small installation and cost very little extra.

Should the customer not be able to afford a new CU and, for some reason (why?), require a single RCD in the supply (there are some/many like this already) I wouldn't consider it a major sin to fit it (with the appropriate explanation). Emphasise - Why?

However, as in a recent thread, I think we are beginning to realise that RCDs are not wonderful, then I cannot really envisage a situation where it would arise.
It would probably be better to fit one just to the socket circuit, or shower, if required.

 

[JohnW2]

If a customer who had an ancient installation/CU (with no RCD protection at all) asked you to install a new CU, but insisted that it should be one which had a single, installation-wide, RCD, would you take the job and, if so, what would you do about the certificate?

No, but that's not the same plus: Why would they?

I obviously can't answer the "Why would they?" question, but I can ask why you would not take the job - presumably because what you were being asked to do would not be compliant with current regs?

A separate RCBO for the lights would satisfy the regulations in a small installation and cost very little extra.

Of course, but, as you say, it would then probably be compliant. The situation we are discussing is one in which the set-up one ends up with would not be compliant with current regs.

Should the customer not be able to afford a new CU and, for some reason (why?), require a single RCD in the supply (there are some/many like this already) I wouldn't consider it a major sin to fit it (with the appropriate explanation). Emphasise - Why?

As I've said, not only wouldn't I consider it to be "a major sin", but I would actually consider it worthwhile if the customer were not prepared to consider any other option. However, yet again, does that mean that you feel that it would be "OK" (bureaucracy-wise) for an electrician to do it?

However, as in a recent thread, I think we are beginning to realise that RCDs are not wonderful, then I cannot really envisage a situation where it would arise. It would probably be better to fit one just to the socket circuit, or shower, if required.

Maybe. As you know, I am one of those who is, at least as yet, far from convinced that RCDs have actually achieved anything much at all, particularly in relation to what has been spent on them. However, those who write the regulations presumably think differently.

Kind Regards, John

 

[WabbitPoo]

Happy to have inspired such a meaningful conversation, even if much of it is over my head!


Still waiting for the elec to come back to me.....

If you are really bored i can post the whole report to see if clarifies anything.

Thanks again.

 

[EFLImpudence]

As I've said, not only wouldn't I consider it to be "a major sin", but I would actually consider it worthwhile if the customer were not prepared to consider any other option. However, yet again, does that mean that you feel that it would be "OK" (bureaucracy-wise) for an electrician to do it?

I would do it if that's what the customer wanted.
Bureaucracy wise? Mmmm. Disclaimers on page 2 of BGB. Plenty of other mistakes.
However I consider it purely hypothetical.

However, those who write the regulations presumably think differently.

Who knows what they are really thinking in some instances?
Disclaimers on page 2.

 

[EFLImpudence]

If you are really bored i can post the whole report to see if clarifies anything.

It may be interesting. Don't show any names.

 

[JohnW2]

... does that mean that you feel that it would be "OK" (bureaucracy-wise) for an electrician to do it?

I would do it if that's what the customer wanted. Bureaucracy wise? Mmmm. Disclaimers on page 2 of BGB.

As I've said, in terms of common sense and safety, I think that's sensible, but, in terms of 'the bureaucracy', what would you, as an electrician, do about the certificate?

However I consider it purely hypothetical.

Is it really? If someone believed (as most do) that RCDs confer a significant improvement in terms of personal safety, if they could not afford anything else (and didn't have a CU which could take an RCBO), might they not ask for a single up-front RCD to be installed?

However, those who write the regulations presumably think differently.

Who knows what they are really thinking in some instances?

True, but it's not just them. Virtually the whole world seems to believe that RCDs were a 'breakthrough' that has resulted in considerable saving of life and limb, even if I personally have yet to see the evidence - either anecdotal or in terms of statistics. IIRC, the proposal for the (I presume) BYB next year would take us even closer to 'all sockets must be RCD protected'.

Kind Regards, John

 

[EFLImpudence]

As I've said, in terms of common sense and safety, I think that's sensible, but, in terms of 'the bureaucracy', what would you, as an electrician, do about the certificate?

Make a note that it was the customer's request and the consequences have been explained ?

However I consider it purely hypothetical.

Is it really? If someone believed (as most do) that RCDs confer a significant improvement in terms of personal safety, if they could not afford anything else (and didn't have a CU which could take an RCBO), might they not ask for a single up-front RCD to be installed?

I don't think they would.
People don't know what they are.

However, those who write the regulations presumably think differently.

Who knows what they are really thinking in some instances?

True, but it's not just them. Virtually the whole world seems to believe that RCDs were a 'breakthrough' that has resulted in considerable saving of life and limb,

I would say virtually the whole world is totally unaware of the existence of RCDs.

 

[JohnW2]

I don't think they would. People don't know what they are. ... I would say virtually the whole world is totally unaware of the existence of RCDs.

Interesting belief. I would probably agree that a high proportion of the general public are probably unaware of RCDs by name/acronym (any name/acronym), but I would have thought that very many are aware of 'the trip switches which stop them getting electrocuted'. Indeed, as we have discussed in the past, it's the belief that RCDs are a 'panacea' that may well make some people somewhat too complacent around electricity. Am I wrong?

Kind Regards, John

 

[AndyPRK]

Prenticeboyofderry usually educates people about RCDs lol.
I think he has shares in an rcd manufacture.


But seriously ppl were aware of rcds in the 1980s