Tightening connections

[Coaster]

Hello.
I have replaced an old light fitting and the old wiring was squashed flat, with strands breaking off.
Can anyone tell me if it's easy to overtighten electrical connections and how to avoid it?
Should I cut the wire back?

 

[kendor]

Hello.
I have replaced an old light fitting and the old wiring was squashed flat, with strands breaking off.
Can anyone tell me if it's easy to overtighten electrical connections and how to avoid it?
Should I cut the wire back?

yes to the first question and to avoid it takes a certain amount of experience so practice on cutoffs first
Yes to the second question.

 

[ban-all-sheds]

the old wiring was squashed flat, with strands breaking off.

Strands?

In the fixed cabling of the lighting circuit?

 

[kai]

Do you still have old 3/.029 cable in your lighting circuits?

 

[HandyJon]

Do you still have old 3/.029 cable in your lighting circuits?

Or in plain english, do you have grey PVC covered wiring or it is cloth or rubber covered?

 

[Careful_Bodger]

Do you still have old 3/.029 cable in your lighting circuits?

...as I have, hence my request (granted thanks) for its current ratings to be posted in the reference section of this forum.

Like the original poster, the strands of my lighting circuit were breaking off at the CU end. Its susceptibility to rough handling is presumably why it was superceded with solid core.

And it is white PVC, incidently.

 

[kendor]

Whether stranded or solid cable has been used it is possible to overtighten connections, with stranded there is a good likelyhood that although some cores will break others will stay intact whereas the solid core just breaks and leaves either an open circuit or worse still an intermediate or arcing connection.

 

[Coaster]

Thanks to all those replying to my question about tight terminal connections.

HaidyJon;
I dod’nt explain myself too well.
Both the grey PVC covered wiring (solid core) and also the stranded 0.75mm flex connected to it via the ceiling rose to the light fitting were both crushed down a bit.

Should there just be a light mark from the terminal screw?

 

[kendor]

Thanks to all those replying to my question about tight terminal connections.

HaidyJon;
I dod’nt explain myself too well.
Both the grey PVC covered wiring (solid core) and also the stranded 0.75mm flex connected to it via the ceiling rose to the light fitting were both crushed down a bit.

Should there just be a light mark from the terminal screw?

It's a very hard one to answer in words as everyone interpretation of light mark and sufficient tightening are purely subjective, that's why tightening of crucial bolts and nuts in say a car engine will have what's called torque ratings so there is no doubt to how hard you tighten them but with regards to electrical connections there are no such guidelines to screw terminal connections such as you are asking about, so practice with the cutoffs and see for yourself how tight a connection you can make before the cable shows signs of damage and after a time you'll get the feel for it.

 

[Panjandrum]

I know this is subjective too, and very "rule of thumb" - but generally I find that the size of connector, the size of conductor and the size of screwdriver that fit the screw come together to mean that tightening up as hard as possible is OK.

 

[kai]

Do you still have old 3/.029 cable in your lighting circuits?

...as I have, hence my request (granted thanks) for its current ratings to be posted in the reference section of this forum.

Like the original poster, the strands of my lighting circuit were breaking off at the CU end. Its susceptibility to rough handling is presumably why it was superceded with solid core.

And it is white PVC, incidently.

I thought that ancient 3/.029 cable was always cotton covered and made of crumbly rubber????