OVERHEATING CABLE

[empip]

Looking here :-
http://www.planningportal.gov.uk/england/professionals/en/1115314808708.html

Consolidated versions of the Building Regulations 2000 and the Building (Approved Inspectors etc.) Regulations 2000

1. The following two links are to informal consolidated versions of the Building Regulations 2000 and the Building (Approved Inspectors etc.) Regulations 2000 respectively. In light of the number of amendments to both sets of Regulations, it is considered that putting these documents on the website would assist users of the Regulations.

http://www.planningportal.gov.uk/Pp....uk/uploads/br/BC_Consolidated_Bldg_Regs.pdf

http://www.planningportal.gov.uk/Pp...ov.uk/uploads/br/BC_Consolidated_AI_Regs.pdf

2. The text of the documents represents only those provisions which were in force when the documents were put onto the website on 13 April 2007.

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[Softus]

I agree that this is a correct consolidation, but you appear to be reading the wrong paragraphs. I'm reading the following one:

1. Work consisting of—
(a) replacing any fixed electrical equipment which does not include the provision of—
(i) any new fixed cabling; or
(ii) a consumer unit;
(b) replacing a damaged cable for a single circuit only;
...

The scenario of the replacement in this topic is closest to (b) above. However, the word "damaged" is open to interpretation. The interpretation has to be reasonable, and lead to a safe installation, and IMHO there is only one such interpretation, which as follows.

1. A cable that has been mechanically damaged, but was previously safe to use, can be replaced without notice being given.

2. A cable whose insulation has broken down as a result of aging, but was previously safe to use, can be replaced without notice being given.

3. A cable that has overheated and whose insulation has melted, ths exposing an unsafe installation, requires a redesign. Therefore the circuit characteristics will change, therefore notice is required to be given and satisfactory documentation is required to be provided.

The OP had an unsafe installation, and, if he has replaced the melted cable with an identical one, following the same route, with the same thermal insulation, then he has recreated the unsafe situation.

 

[JohnD]

Where did you find the bit that mentions what has to be done if "circuit characteristics will change"

 

[Softus]

Where did you find the bit that mentions what has to be done if "circuit characteristics will change"

That was my paraphrase for an interpretation of the SI; since change of circuit characteristics (i.e. CCC, or protective device, or fixed load) is not stated anywhere in the section that defines the exempt work categories, then ipso facto it requires notification.

IMHO.

 

[JohnD]

But neither does the exempt section not say "exempt unless run in a different colour cable" or "exempt unless installed on Tuesday afternoons"

So tell me more about why you interpret it to mean "exempt unless circuit characteristics change"

 

[notyou]

uPDATE
Thanks for the interesting replies.
Did a current load test and the shower is ok I know the cable is OK as its new and tested as is shower switch, I feel the weakness is the aged wylex unit and will be replaced, many thanks for the tips.
Its nice to get some support from time to time

To add to the notifable or not debate, Definatley not notifiably, any damaged or aged cable can be replaced, and a definition of damaged in my opinion is anything not 100%.
This where the part p falls down as it encourages bodged 30a joint boxes connections instead of replacement cables, as its not part p able to run a spur or joint here to do this , but to run a new cable is so it positivly encourages short cuts by bodgers.

 

[Softus]

But neither does the exempt section not say "exempt unless run in a different colour cable" or "exempt unless installed on Tuesday afternoons"

Those are two examples of changes to the installation that could be argued as having no unsafe outcome.

So tell me more about why you interpret it to mean "exempt unless circuit characteristics change"

Because it can all too easily have an unsafe outcome, and the whole essence of Part P is to encourage safe practices and discourage dangerous ones.

I don't have any more ways of telling you that I think my interpretation is reasonable, other than to reiterate my belief that it's reasonable. If you think it's unreasonable, then so be it.
_____________________________

To add to the notifable or not debate, Definatley not notifiably, any damaged or aged cable can be replaced, and a definition of damaged in my opinion is anything not 100%.

I'd like to say that your statement is a neat way of ignoring the suggested interpretation I made in my post, but it wasn't actually very neat.

This where the part p falls down as it encourages bodged 30a joint boxes connections instead of replacement cables, as its not part p able to run a spur or joint here to do this , but to run a new cable is so it positivly encourages short cuts by bodgers.

How does that work?

On the one hand you claim that Part P doesn't require notification for a replacement cable, no matter how that cable become damaged, but on the other hand you claim that Part P discourages people from replacing a damaged cable

You have me baffled - if the introduction of Part P did nothing to make cable replacement difficult or administratively arduous, then how does it encourage people to do those bad things that avoid replacing a cable?

 

[JohnD]

I was hoping not for value judgements on "reasonable/unreasonable" or "safe/unsafe" but for "in Part P/not in Part P"

Replacing a damaged cable
where the modern cable has a bigger CPC than the old
is reasonable and safe but will change the circuit characteristics.

 

[Softus]

I don't think that the entirety of Part P has been well thought out, and that this is one area that exposes its relative youth.

I agree that increasing the CPC will change the characteristics, but is there any way in which such an increase can make the installation less safe?

The overriding objective is to comply with the following:

PART P ELECTRICAL SAFETY

Design and installation

P1 Reasonable provision shall be made in the design and installation of electrical installations in order to protect persons operating, maintaining or altering the installations from fire or injury.

If a cable melts for reason of overloading or underspecifying, and is simply replaced with cable whose phase and neutral conductors are of the same CSA, regardless of the size of CPC, then I don't see how anyone could argue that the consequent installation is protecting persons operating, maintaining or altering the installations from fire or injury.

This doesn't need any definition or interpretation of the word "reasonable", therefore in terms of being either "in Part P/not in Part P", it is unequivocally in Part P.

 

[JohnD]

Then I don't think "the circuit characteristics will change" correctly expresses the factor that you interpret as making it notifiable.

It seems to me that you have in mind changes which make the installation less safe.

In terms of notifiable work, I can't see that changes in circuit characteristics make work notifiable, if it falls in one of the categories that are listed as being non-notifiable; and I haven't spotted anything in the documentation that says it does become notifiable.

 

[Softus]

Then I don't think "the circuit characteristics will change" correctly expresses the factor that you interpret as making it notifiable.

In that case I'll change the wording in the following statement...

3. A cable that has overheated and whose insulation has melted, ths exposing an unsafe installation, requires a redesign. Therefore the circuit characteristics will change, therefore notice is required to be given and satisfactory documentation is required to be provided.

...to be as follows...

3. A cable that has overheated and whose insulation has melted, ths exposing an unsafe installation, requires a redesign. Therefore the circuit characteristics will change. Also, notice is required to be given and satisfactory documentation is required to be provided.

___________________

It seems to me that you have in mind changes which make the installation less safe.

Generally yes, but on this topic no - I have in mind a change which fails to make the installation more safe, and, more importantly, fails to remove the unsafe factor.

In terms of notifiable work, I can't see that changes in circuit characteristics make work notifiable, if it falls in one of the categories that are listed as being non-notifiable; and I haven't spotted anything in the documentation that says it does become notifiable.

Please see modified working above. I believe that the change is (a) notifiable (as already explained), and I believe that the change is unsafe, and thereby in contravention of the BRs.

 

[JohnD]

We'll probably never know about this notyou's case, but it is quite difficult to damage a PVC cable by overloads unless very gross. More often the overheating occurs at badly-made terminations and loose or worn connections, and damage to the cable arising does not indicate a design defect.

Typically, replacement of the overheated accessory, and cutting back (or replacement) of the cable, using good workmanship, is all that is needed. I see no problem is using a more modern, or larger, cable to replace the old one.

 

[Softus]

We'll probably never know about this notyou's case, but it is quite difficult to damage a PVC cable by overloads unless very gross.

...or by thermally insulating the ar*e off it. I believe RF Lighting has a full catalogue of examples of overloads affecting parts of cables other than at the termination points.

More often the overheating occurs at badly-made terminations and loose or worn connections, and damage to the cable arising does not indicate a design defect.

I suspect you're right. Then there are those installations where there is a design defect because the design is defective. Then there are those installations where the cable has been overloaded because the load was increased without reviewing the cable CCC.

Typically, replacement of the overheated accessory, and cutting back (or replacement) of the cable, using good workmanship, is all that is needed. I see no problem is using a more modern, or larger, cable to replace the old one.

But the OP hasn't done that - he/she hasn't said that he/she uprated the cable CCC by increasing its CSA, has he/she?

 

[Spark123]

Is changing a 30A BS3036 fuse to a 45A BS(EN)60898 MCB is non-notifiable though?? I was always under the impression altering the characteristics of the overcurrent protective device is notifiable.

 

[Softus]

I think it's possible to foresee how a court would interpret the BRs and determine the need to notify.

For example, where legislation is ambiguous, the overriding objective would be ascertained first. In this case it's one of discovering work and installations that are unsafe (to persons operating bla bla bla). Then a suitable test is derived; for example, if a change to a circuit or installation was such that an unqualified person could make that change without likelihood of introducing a hazard (to persons etc.), then there's no benefit to notification. However, if a change was capable of making the installation unsafe, and only someone with the qualified knowledge to perform appropriate verification and testing would be able to determine whether or not it had, then clearly (well, clearly to me anyway) that work would be notifiable. Unless the BRs specifically said that it wasn't.

IMHO.

Note that this is only an example of a legislative test - it's not supposed to be a prediction, or a bet, or an invitation to shoot me down or pick holes in it. If you disagree then please debate it by offering an alternative.