Electrical question: stripping ends / crushing wires in terminals

A basic electrical question for you all.
This hasn't been a particular issue so far, because where it did happen I played it safe and re-stripped the ends. But mainly to save effort in future (particularly where there isn't much spare left to re- strip), I'd like to be sure.
1. If, when stripping the inner insulation off twin and earth, you "nick" the core with the strippers slightly, is that likely to cause enough difference to the resistance of that core to make it unsafe?
2. Similarly, will overtightening terminals such that the wire is crushed be a problem, so long as it is not actually broken?
A test with a multimeter showed negligible/no change in resistance where I did this deliberately to a small length of test cable so I'm inclined to say "not a problem" - but am I right?
Thanks
Neil
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

The problem here is not the increase in resistance (negligible as you say), but that nick will act as a stress concentrator, meaning that the wire is much more likely to snap at that point - particularly if it is flexed at all.

I don't think that is a problem (but an expert will be along shortly to correct me). In fact, I would have thought some deformation of the wire was required, to ensure a nice gas-tight contact.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
In article

It would depend on the size of the 'nick'. A mere scratch could be ignored - something that reduces the diameter appreciably best not. But given there are lots of devices around for stripping cable properly, it shouldn't be a question which needs asking.

No - as the cross section remains the same.

You'd need a very specialised meter to measure this sort of very low resistance.

--
*Do infants enjoy infancy as much as adults enjoy adultery?

Dave Plowman snipped-for-privacy@davenoise.co.uk London SW
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Dave Plowman wrote:

I tend to use a small blunt kitchen knife for cable stripping, it cuts the PVC without making any impression on the copper underneath. Taught to me by my sparks instructor 20 years ago.
JGH
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

It takes too long. Any anyway, the kitchen knife is for changing plugs.
--
Adam



Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
ARWadsworth wrote:

The angle grinder wasn't to hand.
JGH
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Like a pair of snips that have cut through a live cable?
--
Adam



Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
ARWadsworth wrote:

Surely you'd need to snip through 1, 1.5 and 2.5 mm^2 live cables to form the correct sized notches for everyday use?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

I have an apprentice.........
--
Adam



Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
ARWadsworth wrote:

Lets hope he learns before he moves onto 4, 6 and 10 mm^2 cables
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Tue, 26 Jul 2011 16:00:22 +0100, ARWadsworth wrote:

Yes, I have a pair of those. Had them for 45 years...
--
Use the BIG mirror service in the UK:
http://www.mirrorservice.org
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Bedded in on some imperial 7/.029 T&E then:-)
--
Adam



Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Tue, 26 Jul 2011 17:44:07 +0100, ARWadsworth wrote:

It was actually some heavy duty rubber insulated flex feeding lighting battens on a stage. I was hanging on to the (earthed) stage framework with the other hand/arm, 30 feet up, at the time.
--
Use the BIG mirror service in the UK:
http://www.mirrorservice.org
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 26/07/2011 18:26, Bob Eager wrote:

RCDs are for wimps....
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Ah. Forgot we had a pro here. ;-)
--
*My dog can lick anyone

Dave Plowman snipped-for-privacy@davenoise.co.uk London SW
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

Have had several pairs of those, and was oh so glad when a professional I employed at one time did the same !
Back on topic - I was always taught to nick the end of the cable and use a pair of pliers to pull out the earth line to strip the outer sheath back. And then I just pull off the required length of the inner insulation with the wire cutters.
Rob
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
robgraham wrote:

I can't quite picture what you're describing there without picturing the cable being damaged. Maybe time for a Wiki entry?
JGH
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

OK - in words of one syllable !!
It's inadvisable to cut the outer sheath with a knife where you want it stripped back to because of the danger of nicking the inner cable insulation - agreed ?
To avoid this, extract the earth lead from the cut end of the cable by making a small nick in the face of the cut end with the wire cutters. Pull the earth wire back to the required length of exposed cable with pliers such that the earth wire cuts the outer sheath. The outer sheath can then be cut off using the wire cutters.
Judicious use of the wire cutters can then strip off the required length of the plastic insulation from the inner cables.
It's always a bit difficult to describe in words what is so easy to show as a demo, so I hope I've got the idea across.
Rob
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
robgraham wrote:

That bit is clear and I suspect most people use that method

I think that's the bit that JGH was worried about, using cutters rather than properly adjusted wire strippers to strip the inner insulation, you can nick the conductor unless you're careful ... but then of course, we're all careful, all the time!
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 27/07/2011 21:05, Andy Burns wrote:

I've used that method, but I've also used another - using a Stanley knife to cut into the end, with just a slight sideways angle so that it slides smoothly down the side of the Earth core without nicking it or the insulation of the phase conductor next to it. It's much easier that way to strip right back into an accessory box.
SteveW
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Site Timeline

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.