change of mcb to rcd

[ban-all-sheds]

Of course, if it's a TT installation, then your argument probably falls flat on it's face, since the RCD is then the only means of providing acceptable fault protection.

Please show us where the regulations permit the use of underground T/E in TT installations as long as it's protected by an RCD.

 

[JohnW2]

I have 4 options
1. cut off the power (That would cause some inconvenience)
2. leave it as it is
3. have it all renewed (not cost effective) it would be expensive
4. make it as safe as possible by other means. Other means being an rcd or rcbo (if an rcbo would do the job)

You know what the 'proper'/safest option is (#3), but you seem to have discounted that. Given that you've started thinking about this, option #2 seems silly - since #4 is clearly better. That leaves you with #1 and #4, and only you can make that decision. As I wrote earlier, changing the MCB to an RCBO would 'do the trick', other than leaving a theoretically 'unsatisfactory' cable in the equation, but clearly would be better than #2 if one were 'compromising'. As I said, your problem would probably be in finding an electrician prepared to change MCB to RCBO with the existing cable, in which case your only remaining option would be to do it yourself (if you felt confident in your ability to do it competently and safely), probably technically illegally.

I know what I would probably do if I were in your position, but I'm not you!

Kind Regards, John

 

[ban-all-sheds]

However, given the OP's subsequent revelations, if he insisted on sticking with the buried T+E, despite advice and despite the fact that it is probably (we're not told if it is protected in any way) unacceptable per current regulations, then it would probably be better to have RCD protection at the house end.

No - despite the OP's subsequent revelations the advice must remain the same as that given by TTC first time around.

 

[ban-all-sheds]

The T&E is buried somewhere under 4" of concrete and I have no desire to dig that lot up at 73 y.o.

Then you'd have to get someone to do that for you.

I have 4 options

No, you don't.

1. cut off the power (That would cause some inconvenience)

But that is Option 1.

2. leave it as it is

Not an option.

3. have it all renewed (not cost effective) it would be expensive

But that is Option 2.

4. make it as safe as possible by other means. Other means being an rcd or rcbo (if an rcbo would do the job)

RCD protection is not a sticking plaster to fix an inappropriate cable. Not an option.

 

[JohnW2]

Of course, if it's a TT installation, then your argument probably falls flat on it's face, since the RCD is then the only means of providing acceptable fault protection.

Please show us where the regulations permit the use of underground T/E in TT installations as long as it's protected by an RCD.

I never suggested that it is permitted - on the contrary, I said that underground T+E is not permitted unless adequately protected - and that is regardless of the discussion about protective devices ('additional' or otherwise). My point (and the part of TTC's argumengt which would fall on its face with TT) is that, in a TT installation, the only thing that can provided the required fault protection is an RCD/RCBO - even if TTC calls it 'only Additional Protection' ('additional' to what, I would have to ask, in that situation).

Kind Regards, John.

 

[JohnW2]

However, given the OP's subsequent revelations, if he insisted on sticking with the buried T+E, despite advice and despite the fact that it is probably (we're not told if it is protected in any way) unacceptable per current regulations, then it would probably be better to have RCD protection at the house end.

No - despite the OP's subsequent revelations the advice must remain the same as that given by TTC first time around.

I am not giving advice (the OP already knows what the best/proper course is) - I was merely talking about what would be the safer of the remaining options IF, despite knowing what he's been told, the OP chose to retain the buried T+E.

Kind Regards, John

 

[ban-all-sheds]

Retaining it is not acceptable.

He should not be told to do anything else except not to carry on using it.

 

[JohnW2]

Retaining it is not acceptable. He should not be told to do anything else except not to carry on using it.

'Acceptable' or not (to you, the regs or whoever), one has to understand that it is a choice he may make.

If it's something which you can do, forget about regs for a moment and think just about 'safety' ... particularly given that one can (I've done it!) put a spade through modest-sized SWA,do you really think that RCD-protected T&E is significantly less safe than non-RCD-protected SWA?

Kind Regards, John

 

[ban-all-sheds]

'Acceptable' or not (to you, the regs or whoever), one has to understand that it is a choice he may make.

It is not a choice which should be validated or facilitated in any way.

 

[JohnW2]

The cable is underground and appears to be basic 2.5mm.

Everyone is assuming that you mean just ordinary 'house wiring' twin+earth cable buried directly in the ground without anything protective (like a 'pipe' of some sort) around it. Is that correct?

Kind Regards, John

 

[stubob]

Buy one of these
http://www.proteusswitchgear.co.uk/product_details.asp?product=4569

 

[RF Lighting]

And do what with it exactly?

 

[JohnW2]

If it's something which you can do, forget about regs for a moment and think just about 'safety' ... particularly given that one can (I've done it!) put a spade through modest-sized SWA,do you really think that RCD-protected T&E is significantly less safe than non-RCD-protected SWA?

When I wrote that, I was forgetting that the T+E is buried under 4 inches of concrete. That being the case, is there really any significant safety issue (particularly if RCD/RCBO protection is added) - in particular such an issue of safety as to warrant BAS writing:

He should not be told to do anything else except not to carry on using it.

... or, put another way, what is the reason for not carrying on using it (particularly if RCD protection is added, which is wants the OP wants to do)? The mere fact that this 13+ year-old circuit is not compliant with current regs is obviously, in itself, not a reason to "not carry on using it"!

Kind Regards, John

 

[ericmark]

Since we don't know if there is a RCBO that will fit the consumer unit and the price of a 13A RCD FCU is little different to a RCBO plus it is double pole I would consider using on of those.

OK I know not ideal but must be better than what he has.

 

[Taylortwocities]

TTC calls it 'only Additional Protection' ('additional' to what, I would have to ask, in that situation).

As detailed in 410.3.2 and Section 415 of the BGB

Additional protection provided by and RCD.

"....use of RCDs as addition to basic and/or fault protection"