Meter Tails

[imroberts]

A couple of quick questions from a relative newbie

1) What's the best tool for cutting and stripping meter tails?

2) Where do you strip off the outer sheath/insulation to and why? I've seen all the following but am undecided what is best.

a) Strip off where the tails enter the CU, leaving the inner colours visible from the entry point to the main switch
b) Strip off at the same point the inner is stripped at the entry to the main switch
c) Strip off a short distance (say 1cm) from where the tails enter the main switch, leaving a short length of visible inner insulation but fully protected throughout the remainder

 

[PrenticeBoyofDerry]

I prefer to expose enough of the core colour, so it can be easily identified and leave the remainder of the sheath on the cable.
You could also flag/tag the conductors outer sheath with the appropriate core colour for easier identification if you wished.
I prefer to use craft/stanley(type) knife to remove sheath and insulation of the conductors.

 

[JohnW2]

A couple of quick questions from a relative newbie

You are almost certainly going to be told that if you are a newbie, and need to ask these questions, you should not be doing anything which requires you to know the answers! Having said that:

1) What's the best tool for cutting and stripping meter tails?

Opinions will vary. I would say heavy duty wire cutters and a Stanley knife, respectively.

2) Where do you strip off the outer sheath/insulation to and why? I've seen all the following but am undecided what is best.
a) Strip off where the tails enter the CU, leaving the inner colours visible from the entry point to the main switch
b) Strip off at the same point the inner is stripped at the entry to the main switch
c) Strip off a short distance (say 1cm) from where the tails enter the main switch, leaving a short length of visible inner insulation but fully protected throughout the remainder

(c) is the probably the best/usual - and as for the 'why' ... maximises amount of insulation present whilst still enabling inner insulation colour (i.e. identification) visible.

Kind Regards, John

 

[dingodeano]

These are my bad boys.

http://www.knipex.com/index.php?id=1216&L=1&page=art_detail&parentID=1324&groupID=1332&artID=356

I use them to 'ring' the insulation and cut the tails as required.

 

[imroberts]

You are almost certainly going to be told that if you are a newbie, and need to ask these questions, you should not be doing anything which requires you to know the answers!

I look forward to it

Thanks for the answers though!

(c) is also my preference for the same reasons, I don't see any point removing insulation where it can be left, but also agree the cores should be easily accessible. I have seen other techniques though so wondered if I was in the minority

 

[Risteard]

Exposing the insulation before it enters the enclosure does not comply with the Wiring Regulations unless there is other mechanical protection, e.g. trunking. Otherwise the sheath must be intact until the cable enters the enclosure.

I know it's standard practice to do that, but it would be better to mark over the sheath with some phase tape.

 

[JohnW2]

Exposing the insulation before it enters the enclosure does not comply with the Wiring Regulations unless there is other mechanical protection, e.g. trunking. Otherwise the sheath must be intact until the cable enters the enclosure.

Very true - but I don't think that was any of the options being suggested. As I read them, the 'worst [(a)] had both insulation and sheathing entering the CU enclosure, with the sheath being stripped from soon thereafter (within CU enclosure) - something I've seen done, but certainly wouldn't advocate.

Kind Regards, John

 

[imroberts]

These are my bad boys.

http://www.knipex.com/index.php?id=1216&L=1&page=art_detail&parentID=1324&groupID=1332&artID=356

I use them to 'ring' the insulation and cut the tails as required.

Your link seems to take me to a plier storage rack

I like the look of Knipex cable shears - probably these or these

 

[SimonH2]

Yes, shear type cutters are essential for that sort of size.

When stripping the sheath, and especially the insulation, it is vital to not cut through and nick the layer below. It takes some practice, but if you cut part way through with the knife, then it will tear and you can remove it without damaging the next layer down.
I "ring" where the sheath/insulation is to be cut from, and then carefully cut along the bit to be removed with the blade almost flat to the cable (like peeling an apple). Once you have taken a section off, you should be able to grip and edge and pull the rest off. Oh yes, and always cut away from you so that the knife doesn't take any bit of your anatomy off when you slip.

Putting the knife into the copper (no matter how slight) is a real no-no as it very severely weakens the copper which can fail when bent a few times. At it's worst, I've been asked to look at an item of equipment which stopped because the last strand in the live core failed - the rest having been cut by an over enthusiastic wielding of a knife.

And at my last job we had an aircon unit that started tripping the breaker in damp weather. The numb-nuts that originally installed it had gone right through the inner sheath and the live core insulation while cutting the wire armour - in damp weather it arced over to the earthed metal behind the clamp.

 

[JohnW2]

Putting the knife into the copper (no matter how slight) is a real no-no as it very severely weakens the copper which can fail when bent a few times. At it's worst, I've been asked to look at an item of equipment which stopped because the last strand in the live core failed - the rest having been cut by an over enthusiastic wielding of a knife.

Whilst that's obviously true as a generalisation, I think one would have to be very heavy-handed with a knife to cause much trouble of that sort with 25mm² conductors.

Kind Regards, John

 

[westie101]

I think one would have to be very heavy-handed with a knife to cause much trouble of that sort with 25mm² conductors.

True, try stripping some 20ft in the air in the middle of the night in winter, a knife is the only way to do it, ask any overhead linesman!

 

[Peet]

I prefer to expose enough of the core colour, so it can be easily identified and leave the remainder of the sheath on the cable.
You could also flag/tag the conductors outer sheath with the appropriate core colour for easier identification if you wished.
I prefer to use craft/stanley(type) knife to remove sheath and insulation of the conductors.

Is there a reason as to why grey sheathed ones are used as opposed to tails with blue & brown outer sheaths? The tails here have blue & brown outer sheaths, I though they weren't double insulated at first but they are.

 

[JohnW2]

Is there a reason as to why grey sheathed ones are used as opposed to tails with blue & brown outer sheaths? The tails here have blue & brown outer sheaths, I though they weren't double insulated at first but they are.

I would guess that it's simply because a grey sheath is considered more aesthetically acceptable (when visible). One other possibility is the one you highlight in what you say - that having sheath and insulation of different colours can leave one in no doubt that it is, indeed, both insulated and sheathed.

Kind Regards, John

 

[dingodeano]

I've only seen double insulated tails in brown and blue used by the suppliers fitters. Which is good because it's a better indication between supplier - consumer.

Mine - http://www.knipex.com/index.php?id=1216&L=1&page=group_detail&parentID=1324&groupID=1333

 

[Johnmelad]

You are almost certainly going to be told that if you are a newbie, and need to ask these questions, you should not be doing anything which requires you to know the answers!

BAS must be having a night off