Crimping and plastering over?

[DNS1]

Asked about this a while back, but read a few things since that have made me wonder if I was doing the right thing...

Got to join 2 pieces of T+E in the middle of a wall for a light switch. The rest of the cabling is plastered over. I'm intending to plaster over the joint too when it's made (currently it's a joint box hanging out a hole in the wall)

I don't want to have to leave it accessible (don't want a box/blanking plate halfway up the wall) so planned to crimp and sleeve, then plaster in.

Was told a while back that this method was compliant, but now I'm not so sure (read a few posts on another forum).

Any tips would be much appreciated. I'm not a pro sparks (obviously!) but intend to be one in few years so want to make sure I get these things right from the beginning.

 

[malcolmsanford]

I have not heard about the prosecutions that Markie was referring to, though I would have quite liked to have argued reg 526.5, as it states one of the following or a combination of and you could I would have argued that you are combining i and iii by the crimp/heat shrink are suitable accessories and that your plaster is forming part of the enclosure with a building material.

Several years ago I asked to renovate several school buildings and like everything else money was of the premium. We were asked to do similar by extending buried cables to new positions by joint.

What I came up with was exposing the cables for about 2 feet and sinking an architrave box into the wall so that the box was sitting about 5mm below the surface, then fitting oval tube on the cable, crimp and heat shrink and put the joint into the box, with a blank plate covering it and then plaster over.

Over the years I have done the same with repairs where running a new cable is not an option. It takes a little longer, a little more work, but I find that the result is a safe buried joint.

 

[clicon357]

The plastered in, crimped joints in heat shrink sleeve, argument has been a failed defence in at least two court cases resulting from electrical accidents.
All you guys that are heat shrink sleeving crimped joints and then plastering over, seem to have forgotten about:
526.5 Every termination and joint in a live conductor or PEN conductor shall be made within one of the following or a combination thereof:
i) A suitable accessory complying with the appropriate product standard.
ii) An equipment enclosure complying with the appropriate product standard.
iii) An enclosure partially formed or completed with building material which is non-combustible when tested to BS476-4
Specifically 526.5 (iii) an enclosure can be PARTIALLY formed or COMPLETED with non-combustible building material tested to BS 476-4. The enclosure CANNOT therefore be made totally from building material.
The most common infringement of this is a crimped termination, covered with supplementary insulation (e.g. heat-shrink sleeve) and buried directly in the wall with building material (e.g. plaster).
Any type of tape or sleeving used in addition to basic insulation, is defined as supplementary insulation, even if it completely encloses the termination it is NOT an enclosure.
Any cable conductors covered with supplementary insulation, to effectively recreate the double insulation of the original cable, needs to be at least equivalent to that of the original cable product standard and would require impulse dielectric strength testing to confirm this. The cable product standards do not specify an impulse withstand capability. However, 412.2.4.1, Note 1, tells us that cable insulation must be at least equivalent to requirements of BS EN 61140 for reinforced insulation, which does specify impulse withstand capability.

Not in any way wanting a row, but taken on it's own (and it says one method or a combination) then how can a properly done crimp NOT comply with 526.5 (i)? So if going for (i) on its own doesn't it negate the whole issue of an enclosure as in an enclosure is not necessary? I would be interested in the specifics of the two case mentioned.

 

[Big n Daft]

Chaps,
If its right or wrong is not the matter here, we can argue regs all day. By creating a joint in a cable we are creating a weak spot, its only good practise and common sense to have a weak spot in a box of some description.
I personally would regard people who put joints in plastered walls as a bit on the rough side.

 

[richy3333]

Does anyone have a link to these prosecutions as I'd be interested to read the detail about them?

 

[Darkwood]

Yes would be interested in the background to said prosecutions, its means nothing using them to back a post and your point up if theirs no Link or ref' of said prosecutions, i can only assume if they are real they were done with basic through crimps and tape, thus damp plaster would have made wall live, or possible plasterer got a belt doing his job.

 

[clicon357]

526.7 recognises that a connection MIGHT NOT be made in an enclosure................

 

[Darkwood]

Chaps,
If its right or wrong is not the matter here, we can argue regs all day. By creating a joint in a cable we are creating a weak spot, its only good practise and common sense to have a weak spot in a box of some description.
I personally would regard people who put joints in plastered walls as a bit on the rough side.

A very short sighted view, a proper ratchet crimper will give a sound joint with a heat shrink crimp, then a second insulating heatshrink sleeve to cover the whole joint is a recognised and often used way of making a joint especially when limited from other alternative solutions, just because you dont personally do this in your day to day job it dosnt mean its wrong, now were you to use standard crimps and a crap crimper with tape wrap then yes your view would be correct, ive employed the correct method quite a few times over the yrs and even had the clark of electrical works approval, by your recogning it would make inline electrical joints with a apoxy resin fill a bad idea but they are used often in supply cables by the DNO and buried in the wet ground, and these babies are carrying much larger currents without consequence.

 

[clicon357]

A very short sighted view, a proper ratchet crimper will give a sound joint with a heat shrink crimp, then a second insulating heatshrink sleeve to cover the whole joint is a recognised and often used way of making a joint especially when limited from other alternative solutions, just because you dont personally do this in your day to day job it dosnt mean its wrong, now were you to use standard crimps and a crap crimper with tape wrap then yes your view would be correct, ive employed the correct method quite a few times over the yrs and even had the clark of electrical works approval, by your recogning it would make inline electrical joints with a apoxy resin fill a bad idea but they are used often in supply cables by the DNO and buried in the wet ground, and these babies are carrying much larger currents without consequence.

Lets go one better on the heat shrink by using the adhesive type that "melts" as it shrinks and glues itself to the cable!

 

[Darkwood]

Lets go one better on the heat shrink by using the adhesive type that "melts" as it shrinks and glues itself to the cable!

i assume you mean amalgamating tape to which as i mentioned in earlier post is ok if spec of tape meets requirements but it drawback is applying a wrap around tape to a possible very tight joint with no spare play to roll tape around the read of joint, plus its alot bulkier and requires to be set deeper.

 

[clicon357]

i assume you mean amalgamating tape to which as i mentioned in earlier post is ok if spec of tape meets requirements but it drawback is applying a wrap around tape to a possible very tight joint with no spare play to roll tape around the read of joint, plus its alot bulkier and requires to be set deeper.

No, looks like normal heat shrink but when you heat it up the inside goes well...........sticky! Its "adhesive lined". Forms a nice "stuck" joint against the cable sheath. For instance RS stock number 157-3795 - not saying this particular one -just an example, someone's bound to kick off over the dielectric strength! I can imagine this would help guard against the damp plaster getting in.

 

[Darkwood]

No, looks like normal heat shrink but when you heat it up the inside goes well...........sticky! Its "adhesive lined". Forms a nice "stuck" joint against the cable sheath. For instance RS stock number 157-3795 - not saying this particular one -just an example, someone's bound to kick off over the dielectric strength! I can imagine this would help guard against the damp plaster getting in.

Yes self sealing i mentioned it in earlier post to give moisture tight sleeve, thought you'd found a new material then that i missed, luckily im still level with technology