Inline Crimps

[The Medway Handyman]

Hi

I have to repair a lighting cable that someone has drilled through. It's to the two way switch in the hall and the 4 core cable that has been damaged. The damage is about 6" from the ceiling.

The cable is covered by white PVC channel.

I can see three options here;

1] Take up floorboard above & use junction box, replace entire cable. This is the most difficult option because the bedroom above will have to be all but emptied, a section of chipboard cut out & replaced.

2] Cut out small damaged section of cable, use cable crimps to re join, bury in new plaster. There is enough slack to do this. Simplest option, cheapest for customer.

3] Chase out & expose entire cable, remove cable between damage & switch. Crimp new piece of cable to existing, push crimped section into ceiling void, make good. Sort of mid way choice for customer.

Option 1 seems the best to me but it's going to create major disruption. Option 2 is easier, but is it safe & legal?

What's the point in PVC channel anyway? It offers little protection. Is it just to make thing easier for the plasterers?

[Dave Plowman (News)]

As well as crimping you need to use heatshrink to restore the second insulation layer of TW&E.

Indeed. Never use the stuff.

[Stephen Dawson]

I am going to put a damper on things here. I fully support the 'handyman principle', but I think you should draw a line at what you do for reward. I hope for your sake when you carry out these repairs your fully test them and issue the appropriate test certification. Before anyones flames me, be aware that Dave is a trader and not a diy'er, and feeds of the group for advice to carry out his business, which I think has a proper place.

Please do not take this personally but I feel that you stick to what you are good at and capable of.

Steve Dawson

[Derek ^]

On Fri, 17 Nov 2006 22:02:23 GMT, "Stephen Dawson" wrote: {snip]

I've never known an niceic Sparks do anything of the kind.

He snatches the fivers (£200/day) and stuffs them in his back pocket as he says "you don't want to pay VAT do you ?"

And *yes* I am talking from experience. :-(

???

He's not he's a Broadcast sound engineer !

has a proper place.

That has no meaning in the English language.

This is uk.diy AIUI bona-fide contributions are welcome from those that can help.

I have a degree in electrical engineering (1969), that's not to say that I'm up to date with the wiring regs, but I saw nothing in Dave's helpful post the could be criticised.

AAMOF I don't see the point in PVC channel myself.

DG

[Dave Plowman (News)]

What test certification is appropriate in this circumstance?

[The Medway Handyman]

AFAIK repairs to an existing circuit are outside of part P and don't need certification. If I do any electrical work I always double check what I am doing and if I'm not sure I ether ask, look it up or refuse the job.

I make no secret of the fact that I am a 'trader' (hence my signature), but I was a member of this group before that. Many other members are also 'traders'. I do ask questions of those wiser & more experienced than I am granted. I also freely offer my specialist knowledge of pressure washers, carpet cleaning & vacuum cleaners.

I don't 'feed of (sic) the group', I am a regular contributor - which is more than I can say for you. This is a double edged sword of course. Being a 'trader' means that I do more DIY in a month than some do in a year. For example I've built 5 decks this year and I freely share my experience with the diy'er's here, both on & off group.

I do stick to what I'm good at. The client in question had called several electricians to get the problem sorted and none had bothered to get back to her.

Fox Electrical????? I assume that you are also a 'trader'? What are you doing on this group when you don't contribute your knowledge & experience?

[Dave Plowman (News)]

Other Dave. ;-)

[Guy King]

The message from "Stephen Dawson" contains these words:

You've not been here long, have you?

[John Rumm]

So long as you use heatshrink to insulate each wire, and a second layer to insulate the whole join then you will be fine. It helps if you cut each wire a different length such that you don't end up with a bunch of crimps beside each other which will make getting the overall heatshrink on a tad trickey!

To test your work you could disconnect the cable at both switches and then short all the conductors together at one. Now use a low ohms range to measure resistance between them at the other end. That should prove you have a low resistance join. You can compare your readings with the resitance / metre tables in the OSG (assuming you know the approximate length of cable).

Basically yes - protects the cable from trowel damage, and holds it flat to the wall. It is sod all use later should you want to extract and replace a cable.

[gort]

And what are you then, going by your sig ?. Dave has been on this group for a long time and has always given good advice. I have never, ever seen him abuse that. How long have you been posting here ?

Dave

[Andy Burns]

I thought even part-P allowed for replacement of damaged cable in part of an existing circuit.

[Roger R]

I don't understand why you say it is no use later if extraction and replacement of the cable is required. I would have thought that was the principal advantage, please advise.

Roger R

[Dave Plowman (News)]

My thoughts too. But that doesn't stop 'pros' trying to con you into believing otherwise.

[Andrew Gabriel]

I have rewired a house, and made extensive use of the capping whereby I used the old wires to pull the new wires through. There was only one piece in the whole house I couldn't pull out.

Oval trunking is easier, but that's not normally used for first fix in a new building as it's thicker.

[Dave Plowman (News)]

It will be ok in short straight runs, and if carefully lined up at the entrance to a box. But life is rarely that simple. ;-)

Besides, the chances of a re-wire in some 50 years time requiring the same cable runs are remote.

[The Medway Handyman]

Thanks for your good advice as usual John, but I'm now a little confused!

How do you go about fitting heatshrink to each wire? Each wire still has its own insulation apart from the bit inside the crimp. Or do you mean heatshrink just over the crimp? Or would you pull the heatshrink back, make the crimp & then allow it to spring back?

I do see the point about staggering the crimps - good tip.

Perhaps I'm having a blond moment :-)

[Andy Hall]

Well Gloria...... ;-)

You can get heatshrink sleeve with hot melt glue inside. RS sell it among others. Unshrunk size bigger than outer cable insulation - one size is suitable for 1mm^2 to 2.5mm^2 so no need to buy different ones. 4mm^2 and above needs a bigger size probably.

Slide a length longer than the total length of the joint - i.e. lengths of the (now) single insulated sections plus the crimps and a bit more to overlap onto the cable outer insulation at each end - over one cable before you start. Make crimps as described. Slide sleeve over the whole lot and apply heat from heat gun.

Ordinary heat shrink can also be used, but the stuff with glue makes a really good joint that is effectively sealed as well.

[The Medway Handyman]

Only on Friday nights............

Yup, I'm with you.

Yup, got that, but I thought John was suggesting each individual wire should be heat shrinked and then the whole lot heat shrinked?

Where did I put that peroxide...........

[fred]

Hi Dave,

First of all let me say that I value your contribution to this group.

There are many traders posting useful advice here but I think you are unique in that you frequently make posts requesting information on how to best do jobs that you are going to perform for financial gain. That being the case I can see how some could view those posts being of a commercial nature and therefore OT.

My own thoughts are that although you are being paid for these jobs, you are in effect a paid DIYer and so the advice you seek is useful and relevant to others and therefore OK. If however this group was to be flooded by numerous Brand X handymen asking how best to perform their paid work, I think my opinion would change.

I don't think that a trader's name in a sig makes Steve Dawson's or any others' posts commercial.

Please keep contributing.

[The Medway Handyman]

As I said earlier, its a double edged sword. What I learn from doing jobs for commercial gain I happily share with the group. For example I've built

5 decks this year, more than anyone who is not a trader would probably build in a lifetime of DIY. I freely share what I have learnt with anyone here.

I hope I don't abuse the facility. I frequently try to answer questions where I have specialist knowledge or experience. I wrote the pressure washers FAQ to share my knowledge and one day I will finish the carpet cleaning FAQ :-(

I think I contribute as much as I ask at any rate. As you say, my questions and the answers may help others on the group and contribute to the archives.

I agree. I'm not looking for something for nothing though. It wouldn't be right to only ask questions without giving something back.

I will :-)