domestic wiring paranoia

[JJ]

new ring all wired up and waiting connection to CU, which I will do once I have performed standard tests on it.

my question is how do people deal with paranoia issues? for example.. I am always worried that the action of pushing the fitting back into the pattress has found a weakness in my stripping, twisting, screwing in and loosened a cable or something. My standard practice is to leave it over night then unscrew the fitting and tug on the wires with needle nosed pliers to check they are still all secure - its total paranoia I realize, I should just trust my handiwork.

Failing that I should trust the RCBO to detect faults (as it did when I trod a junction box in the loft and ended up rewiring my whole upstairs light ring, only with no junction boxes).

What do sparkies do? they clearly don't have time to double check all their work - do they push it into place on the pattress then pull it out again and visually inspect? or do they never make errors?

What do DIYers do? do they worry about every little detail in their work?

JJ :)

[Usenet Nutter]

I'm sure others who do this regularly will concur that the problem is part paranoia and part something else but I have found that it's best to just have enough outer insulation stripped within the box and cut the wires at the right length so that you don't overcrowd the box when you push them back in with the faceplate . When you do push the faceplate back it will naturally fold the wires so possibly you could bend the wires yourself so they fit in to place neatly as you screw the faceplate on . Along with making sure the wires are held securely on the faceplate and no bare wires are showing . And stop fretting ....:-)

[ARWadsworth]

Hi mate

The ideal thing to do would be an insulation and proper continuity test at the CU.

You can forget the insulation test if you do not have the tester. If you have trapped a cable then the RCBO will let you know. Personally I do not twist cables together. It does not matter that you have decided to do this but I do not recommend it.

Even a simple continuity check of the LL, NN and EE of the ring at the CU is all you need to make sure that a cable has not "popped out".

A good tug on the wires when you first install the socket is all you really need to do to check that they are secure.

HTH

Adam

[JimK]

surely your "standard tests" will reveal any wiring clangers *before* you get to the RCD bit?

JimK

[Andy Dingley]

I buy decent fittings. Well machined cable clamp screws give far fewer problems than loose rattly ones.

[Dave Osborne]

Sparkies develop (from training and experience) an understanding of what can go wrong and how it goes wrong and learn over time how to do it right the first time. There are a few things that can go wrong, such as: -

- Not stripping the wire cleanly, i.e. leaving nicks in the copper which can fracture.

- Not getting wire(s) seated in the terminal properly.

- Not tightening up the terminal screw properly.

- Trapping or crushing the wires when offering the plate up to the backbox.

Good tools and good technique will ensure that these faults can't or don't happen. However, good sparkies do *of course* double check their work. They will have been taught to do so and will take flack from their colleagues if shoddy work is subsequently discovered (as it may well be after testing).

For me, I always visually inspect (to make sure that the wires are correctly seated and that L & N are not swapped), I usually tweak the terminal screws and I usually re-arrange the wires behind a socket if it's hard to push the socket plate to its final resting place. I wouldn't go so far as to check the next morning.

Well, like anything in life, it depends on the person. Some people are bodgers. Worse, some people are ignorant bodgers. Others take a professional (good enough) view and some take a perfectionist view. This applies to both amateurs and professionals.

There are a good few people on this NG who like to do things properly, even if it takes longer or is more expensive. After all, the Diyer has to live with their own work and suffer the consequences of a poor job.

[Dave Plowman (News)]

Tighten the screws *properly* using an ordinary screwdriver where the blade and shaft is the same width as the screws. *Not* an 'electrician's' type. I've never ever broken a screw doing this - but I've come across plenty which haven't been tightened properly and have failed. Cable won't come to any harm through being flexed back into position. Try breaking a spare bit by flexing it back and forwards to see what I mean.

[Roger Mills]

Make sure the screws are tight, and 'help' the cables to fold into place neatly when replacing the faceplate. In particular, make sure that all cables are well clear of the screws. Many years ago - when I was young and foolish(!) - I managed to get a live wire in such a place that the screw cut through the insulation when I did it up - resulting in a big bang and a somewhat blackened fitting when I turned the mains on. With any luck, you only do that *once*!

[ARWadsworth]

Tilers are sent on special courses to help them them do that.

Adam

[Tim Watts]

JJ wibbled on Wednesday 27 January 2010 12:17

I

a) Use 35mm back boxes (accept you may be rewiring into existing shallower ones)

b) I use the "wire is as long as the diagonal of the box" rule of thumb. Then I form the wires into smooth loops so that they tend to collapse helically when the plate is replaced. Doing this right helps avoids the screws. I also accept this is more difficult with a 25mm box.

c) I test everything using a low ohms meter (Megger, but if you have a high quality multimeter, it would go a long way to being useful) and an insulation test. Even a low quality meter will find basic breaks and gratuitous problems. Are you familiar with end-end and "figure-8" tests? You need a test plug for the latter, so you can short the wires at the CU then make tests at every socket.

HTH

Tim

[JJ]

thanks for the feedback, in answer to points ..

- the continuity test and continuity test will follow before connection, I do have the proper testers but they are out of cal and SH - I run on the assumption thats better then nothing. (I don't have a loop tester, but I have everything else).

- the twisting of ring elements is an interesting point. I do it because I read in the docs that its recommended, though other people here clearly think its a bad idea. I know firsthand that it does weaken the copper doing it, but it also reducing the chances of a single section becoming unattached. whats the official recommendation on this one? I don't remember seeing any reference in 17th on it.

- if I make an error then the RCBO will trip and a basic error will be found by my plug tester anyhow, never had one yet.

- I guess I am paranoid and finicky, but on the plus side I do not have a great tendency to bodge things together....

once again, thanks for your thoughts.

[Dave Plowman (News)]

I have mixed thoughts on this. I always used to do it - just tight enough so they wouldn't separate when inserting in the terminal. That way you could be sure all were fully seated - especially when three. But now I don't. I use an insulation stripping tool which can be set to a length and strip off the insulation just a tiny bit more than the depth of the hole. So a quick glance shows them all properly seated.

[David J]

I always used to 'tin' the ends of my DIY house wiring after stripping it to the right length and before poking into a fitting. So often I found that wiring by 'professionals' was merely making contact via a few strands because of unravelling at the ends.

DJ

[The Medway Handyman]

I always use a plug in tester, which should throw up any wire thats come out. Won't detect a loose wire of course.

[John]

I did the same when fitting a new dimmer switch. It damaged the cable so I had to run in a new length as it wasn't long enough after I cut out the damaged bit.

[Tim..]

Yep, been there, done that!!!!

Tim..

[Usenet Nutter]

And me !!!

[Usenet Nutter]

Would there be any advantage in having a small section of softish metal tubing that you could slip over the end of the conductors which would be crushed down when you tightened the screw ...or...something you crimped over the end which would keep the strands all together .

I'm sure I have seen something similar on flex on items that I have bought as well as some where the ends have been tinned

[John Rumm]

Personally I never twist (and I don't shove several earth in a single bit of sleeving either!) on the grounds that it makes testing a future maintenance much simpler if you can break a circuit easily at a socket. Its also easier to get more wires into a terminal if not twisted I find.

Using sockets with good terminals (I tend to buy ones from TLC's ultimate range - nice big square terminals with a proper clamp rather than just a screw) helps. As does using a decent sized screwdriver that you know can torque the screws well enough to get a good clamp.

Using 35mm deep backboxes also helps the arrangement of wires. As does learning what length of wire works well for a given socket design.

In general, mistakes on socket circuits are rare if doing one from scratch with similar sockets at each location. Loop resistance tests will find nearly all the problems. A final insulation resistance test will give confidence that you have not nicked any wires when fixing sockets.

Nothing wrong with that where wiring is concerned!

[John Rumm]

Does not detect a broken ring either when a single wire pops out of a terminal...