Hi, I have an existing 6mm TandE cable, at the consumer unit the sheath is white, at the other end, in the loft, the sheath is grey. The cable is dead. The cable is obviously joined somewhere. My question is, if the cable tests ok ie insulation resistance, continuity etc would you guys be happy to connect it to an 8.5kw shower or due to the hidden jb would you rather not? Many thanks.
Hidden junction box
- Thread starter Scalpel
- Start date
Sponsored Links
- Joined
- 27 Jan 2008
- Messages
- 23,667
- Reaction score
- 2,666
- Location
- Llanfair Caereinion, Nr Welshpool
- Country
The cable is often joined at an isolator but the colour is what worries me a bit. White often means thermosetting (90 deg C) but grey normally thermoplastic (70 deg C) and with Reference Method B (enclosed in conduit on a wall or in trunking etc.) as an example the current carrying capacity jumps from 44 Amp to 38 Amp so to down rate the cable like that would not comply with:-
433.2.1 Except where Regulation 433.2.2 or 433.3 applies, a device for protection against overload shall be installed at the point where a reduction occurs in the value of the current-carrying capacity of the conductors of the
installation.
NOTE: A reduction in current-carrying capacity may be due to a change in cross-sectional area, method of installation, type of cable or conductor, or in environmental conditions.
So as to if any one would use the cable is something they would have to decide after inspection.
433.2.1 Except where Regulation 433.2.2 or 433.3 applies, a device for protection against overload shall be installed at the point where a reduction occurs in the value of the current-carrying capacity of the conductors of the
installation.
NOTE: A reduction in current-carrying capacity may be due to a change in cross-sectional area, method of installation, type of cable or conductor, or in environmental conditions.
So as to if any one would use the cable is something they would have to decide after inspection.
So basically, no.
Also, what do you mean by "the cable is dead"?
Also, what do you mean by "the cable is dead"?
Sponsored Links
Does not sound like a safe option, unless further investigation was to take place. Are you aware if this was an original circuit for a shower, as there maybe good reasons why it was disconnected.
First step would be to see if there is an old isolation point, quite commonly pull cords, so you may find a connection within the ceiling space above the bathroom that was once connected to an isolator or could still be!
First step would be to see if there is an old isolation point, quite commonly pull cords, so you may find a connection within the ceiling space above the bathroom that was once connected to an isolator or could still be!
If it is 'old colours' cable (red/black)', then the sheathing colour obviously means very little, other than (as the OP implied) it cannot be a continuous uninterrupted run of cable.
Such a device is not required if the entire circuit is protected with a device appropriate for the lower-rated cable and, of course, one would not use the cable to supply a load in excess of that which both of the known parts of the cable run were rated to carry.
As has already been mentioned, the main reason for being very hesitant to use such a pre-exsting cable, even if the CCC (at both ends!) is adequate and all parts of the cable are satisfactorily protected by an OPD, is surely that it is impossible to be certain that there are no branches ending in exposed conductors lying around somewhere?
Kind Regards, John.
Without exposing the entire circuit it is never possible to be certain of that.
Exactly - which is why I would never use such a cable unless (a) I had exposed the entire circuit OR (b) I had installed the entire circuit and had adequate documentation of what I had done OR, possibly, (c) if the entire circuit has been installed and documented by someone in whom I had a high degree of trust.
Kind Regards, John.
What if the "such a cable" was the same colour at each end, and checked out fine for continuity and IR?
If I were in a foolhardy frame of mine, I might be tempted, but it would be very unwise without knowledge of the history of the circuit. If I knew, for example, when it had been installed, and that it had been installed as a dedicated circuit for a single known fixed load (e.g. shower, immersion or oven), I might be more tempted. However, when I came to this house, I inherited enough (mainly hidden) JB's, many sprouting mutiple cables, to open a warehouse - and so would do nothing with a cable if all I knew about it were two ends and continuity/IR results!
Kind Regards, John.
Oh come on John don't be so silly. Are you meaning to say that if you had a cable going from one part of your house to another that you would not be happy to energise it unless you had checked out it's entire route?
What if you moved into a new house and the last owners had turned off the electrics before they left? Would you rip up all the walls and chip off all the plaster to make sure there weren't any "dangerous hidden conductors" anywhere?
What if you moved into a new house and the last owners had turned off the electrics before they left? Would you rip up all the walls and chip off all the plaster to make sure there weren't any "dangerous hidden conductors" anywhere?
If it were a disused cable whose history I did not know, I would be very reluctant to use it without a lot of investigation, certainly in a house like mine was when I moved into it. As I said, if I knew the history of the cable, it would probably be different.
That's totally different from finding two unused cable ends about which one knew nothing other than that there was continuity bewteen those two ends, and satisfactory IR.
Kind Regards, John.
I'm with John here - perhaps that cable was disconnected from live because of a safety risk, a break to the cable mid-route or otherwise.
It isn't always possible to remove a cable from a house if it's no longer in use, or dangerous and even I (as a non spark) wouldn't re-energise a cable unless I could trace it fully, or had installed it personally.
I cannot help with the legalities/safetyness that others can, but I would hunt it down from a piece of mind perspective.
I was helping with some work a while ago (non electrical) which required lifiting floor boards... low and behold the person who did some/all of the wiring decided it was a good idea to use a telephone splitter as a junction box on a 2.5mm socket circuit.
If anything electrical is hidden that you cannot determine what it is, do not let it lie.
I was helping with some work a while ago (non electrical) which required lifiting floor boards... low and behold the person who did some/all of the wiring decided it was a good idea to use a telephone splitter as a junction box on a 2.5mm socket circuit.
If anything electrical is hidden that you cannot determine what it is, do not let it lie.
DIYnot Local
Staff member
If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.
Select the supplier or trade you require, enter your location to begin your search.
Are you a trade or supplier? You can create your listing free at DIYnot Local
Sponsored Links
