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.

 

[trev]

I may be wrong but I doubt it would comply, it's not something I'd be comfortable doing mate. I would either pull a new cable in which would not take that long or if you can get access joint it above the switch drop. New cable is the way forward though

 

[PC Electrics]

As long as the crimping is done properly (with ratchet crimp pliers) and you reinstate the sheath with heatshrink or self amalgamating tape (several layers) then you may bury the joint in plaster.

 

[Deleted member 9648]

Never ok to plaster crimps in IMO....but others on here will disagree from previous experience. Pull the cable up under the floor and extend using a compliant JB.

 

[Rockingit]

Personally, can't see an issue so long as the whole joint is robust and done properly. You could actually argue that the short lengths of conductor INSIDE the crimps are mechanically more protected than the rest of the cable. Crimp and shrink is an approved MF method, plastering cable is an approved method. So where's the problem?

 

[Octopus]

Surely you'd cap the cable/joint?

 

[spark 68]

I have on occasion had to use this method.

You need to heatshrink the entire cable afterwards (replacing the sheath), also it is better to stagger your crimps to save a bit of space amongst other reasons.

BTW you can get 'shrinkable' buttsplice crimps, these are covered by heatshrinkable insulation, with a sort of adhesive (which melts) internal to the insulation.

 

[trev]

Ok I'll admit I'm wrong, it's still not something I'd be comfortable doing. It just seems a bit rough to me.
I know there are the arguments about the customer paying for unnecessary work but what's Mr & Mrs Client going to think if they see that going on?

 

[lamb]

Capping protects the cable from the plasterer's trowel and is not a requirement. So if he is filling the wall himself there is no risk of plasterer's mashing the cable so no need for capping IMO

 

[topquark]

If I had to do this, I'd rather solder it and heat shrink it. Both methods are allowable under the regs though.

 

[GLENNSPARK]

I dont like this.....Has the o/p even checked to see of the cable is in a capping/channel?.....if so then just use the old cable to draw a new one in....or alternatevely.....chase out and install new......the wall`s damaged and will need plastering anyway so whats the point....might as well do it right....or not even start the job at all.......

 

[Rockingit]

I'm not suggesting that this is an example of best practice, far from it, but the OP's question was 'is it allowed?'. And the answer is yes, as far as I can see.

 

[GLENNSPARK]

well i wouldn`t do it.....just my own preferance..thats all.......

 

[spark 68]

Agreed Glenn,

I dont like this.....Has the o/p even checked to see of the cable is in a capping/channel?.....if so then just use the old cable to draw a new one in..

and Rock

I'm not suggesting that this is an example of best practice,

I don't like it either, nor is it best practice, I would also seek to replace the run whenever possible, but on occasion where this is not possible (preferrable may be a better term), this method can be used.

If you do use this method, it is better to do it properly though, unlike where on rewires/partial rewires I have seen either live cables or chock blocks just left in the wall (the existing cables to be renewed)

 

[Rockingit]

From a customers perspective, it's the difference between a few pence for some bits and half an hour of labour, or half a day of mess and floorboards, replastering and a big bill. When needs must, needs must.

 

[MarkieSparkie]

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.

 

[Rockingit]

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, 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 the cable insulation must be at least equivalent to requirements of BS EN 61140 for reinforced insulation.

Where are you quoting this from?

 

[Darkwood]

Lets just establish what is needed hear, as i went to college 20yrs ago for 4 yrs instead of the fast track 2 yr courses that i see nowadays, you actually got indepth discussions on everything as well as the basics required. Well to establish just crimping the cable wont suffice; the cable is double insulated for a reason the inner insulation gives the required dielectric strength under the normal working conditions of the cable, the outer sheath is on to protect the inner insulation from environmental effects that the cable would need to put up with under normal operation including damp and chemicals associated with plaster and walls etc.. even if capped over there is a possibility of damp in the wall effecting the joint.
What you need to acheive here is the same standard of insulation and environmental protection as a good piece of cable would acheive. One way of which ive utilised in the past is heat shrink crimps for the joint with a shrinkable sleeve to extend fully across the joint with a overlap onto the good section of cable. This then gives a joint that can be plastered over, also to mention its wise to get sleeving which has a glue/paste that seals the joint from moisture inpregnation.

If this is a one off its an expensive route to go as you may need to buy a heat gun etc, but an amalgamating tape (as mentioned above) may suffice if you read the spec up on the tape to see if it meets requirements for the situe but is arkward to put on as it required to be wrapped on taut and as you dont have access to swing it behind the cable it could be a poor seal.
Poor joints may give questionable IR readings at some point thus leading to a possible repair or replacement of the offending cable and not worth the risk to attempt a joint your not entirely sure of.

 

[GLENNSPARK]

Lets just establish what is needed hear, as i went to college 20yrs ago for 4 yrs instead of the fast track 2 yr courses that i see nowadays, you actually got indepth discussions on everything as well as the basics required. Well to establish just crimping the cable wont suffice; the cable is double insulated for a reason the inner insulation gives the required dielectric strength under the normal working conditions of the cable, the outer sheath is on to protect the inner insulation from environmental effects that the cable would need to put up with under normal operation including damp and chemicals associated with plaster and walls etc.. even if capped over there is a possibility of damp in the wall effecting the joint.
What you need to acheive here is the same standard of insulation and environmental protection as a good piece of cable would acheive. One way of which ive utilised in the past is heat shrink crimps for the joint with a shrinkable sleeve to extend fully across the joint with a overlap onto the good section of cable. This then gives a joint that can be plastered over, also to mention its wise to get sleeving which has a glue/paste that seals the joint from moisture inpregnation.

If this is a one off its an expensive route to go as you may need to buy a heat gun etc, but an amalgamating tape (as mentioned above) may suffice if you read the spec up on the tape to see if it meets requirements for the situe but is arkward to put on as it required to be wrapped on taut and as you dont have access to swing it behind the cable it could be a poor seal.
Poor joints may give questionable IR readings at some point thus leading to a possible repair or replacement of the offending cable and not worth the risk to attempt a joint your not entirely sure of.

well i understand what you are saying here....but also for one length of cable......just pull a new in far gawds sake..lol....:icon6:

 

[Darkwood]

well i understand what you are saying here....but also for one length of cable......just pull a new in far gawds sake..lol....:icon6:

LOL yes agree but occassionally not an option ..... her new tiled bathroom floor above with underfloor heating, the cable drop down the back of a joist close to wall so no real useful access underneath either, but in my yrs only ever used this method twice because of limitations to access the cable.

 

[Darkwood]

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, 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 the cable insulation must be at least equivalent to requirements of BS EN 61140 for reinforced insulation.

I also struggle to find this anywhere i assume its an interpetation from yourself of the reg', regardless of this their are shrinkcrimps and heatshrink sleeving aplenty out there that meets and goes well beyond the requirements of the joint for dielectric strength and environmental protection, just review any spec' sheet related to the heat shrink and you'll find it give a higher degree of protection than the original insulation does, but you do end up paying over the odds for very short bits of sleeving.

 

[GLENNSPARK]

LOL yes agree but occassionally not an option ..... her new tiled bathroom floor above with underfloor heating, the cable drop down the back of a joist close to wall so no real useful access underneath either, but in my yrs only ever used this method twice because of limitations to access the cable.

No probs dark.....you see this kind of thread can quickly become a yes n no camp....with slanging....like a chimps party..lolffs....:tounge_smile:

 

[SoulTy1066]

a box and blank plate tells where the cable drop is. If it's jointed and plastered then how would anyone know that there is a cable there?

 

[trev]

a box and blank plate tells where the cable drop is. If it's jointed and plastered then how would anyone know that there is a cable there?

Because the cable will be in a safe zone designated by the position of the switch..hopefully

 

[SoulTy1066]

i may be being thick but if the switch is removed then it wouldn't be in a safe zone ? you wouldn't know the cable was there

 

[Des 56]

You may be an ex contributor to this forum unless you edit that post

 

[trev]

The op hasn't mentioned removing the switch mate. I understand what you're saying though. the thing is any accessory can be removed at a later date and we can't install with future idiots in mind can we?
By the way themods are having a clampdown on even implied bad language, twould be bad crack for you to get a telling off

 

[Marvo]

i may be being a **** **** but if the switch is removed then it wouldn't be in a safe zone ? you wouldn't know the cable was there

Using Spoonerisms isn't a way to sidestep the 'zero tolerance for bad language' policy of the forum. Please be warned.

 

[DNS1]

Oh crap, hadn't expected this to turn into a 3 page thread!

Here's the story...

Doorway moved from one corner of the room to another (10 feet down same wall). Switch needed to be moved horizontally across the wall. The cable to the original switch came from directly above it.

To keep the original cable in a safe zone, I installed a double socket directly below the location of the old switch. I ran the new cable horizontally to the new switch (chased and plastered).

Yes, it would have been good to have been able to replace the whole cable run, but simply not an option in this case. No access from above without removing a laminate floor.

 

[Rockingit]

Yes, it would have been good to have been able to replace the whole cable run, but simply not an option in this case. No access from above without removing a laminate floor.

Which very neatly upholds my comment that when needs must, they must.

 

[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