Crimping of flexible conductors

richyj · Jul 20, 2015

Hi Guys

Is there any regulations or guidance on whether to use indent crimpers or hex crimpers?

Darkwood · Jul 20, 2015

Welcome to the forum richyj from the staff

Doomed · Jul 20, 2015

I have different sets of crimpers for crimping different things, 5 sets as far as I can think at the moment.

tigerpaul · Jul 20, 2015

One place I work insists on hex crimping. Though I find the crimper we use to be a bit hit and miss regarding the quality of the crimp. For my own stuff I use a normal crimper that punches into the back of the lug. It might not look as pretty but it gives a good solid crimp in my opinion.

Richard Burns · Jul 20, 2015

Welcome to the forum.
I do not think there are any specific wiring regulations about crimps as it is more a tooling issue, however the crimping tool should be suitable for the size and type of crimp in use. So long as the tool and the crimp are compatible and both undamaged then the actual method of crimping should not be an issue.

Deleted member 26818 · Jul 20, 2015

No there is nothing in the Regulations regarding type of crimp.
However, many clients are now specifying hex.

uksparks · Jul 20, 2015

How small is the conductor?

tigerpaul · Jul 20, 2015

Or you can always smash it tight with a lump hammer! :shame::shame::shame::shame::shame::shame::stupid::stupid:

Michaelwgroves · Aug 2, 2015

I've just been reading the IET requirements for electrical installations 17th edition.
526.9.1 states "in order to avoid inappropriate seperation or spreading of individual wires of multi wire, fine wire or very fine wire conductors, suitable terminals shall be used or the conductor ends should be suitably treated."
526.9.2 states "soldering (tinning) of the whole conductor end of multi wire, fine wire and very fine wire conductors is not permitted if screw terminals are used. "

I've always twisted and doubled over; C&G 2365 say this is okay. But you must be careful of not over tightening in case you damage the fine wires. Although the more I think about it I will probably treat myself to some quality Hez crimpers.

So we know we can use "suitable terminals", (assume crimping), but can't tin; so otherwise what else is "suitably treated" ?

shanky887614 · Aug 2, 2015

Michaelwgroves said:
I've just been reading the IET requirements for electrical installations 17th edition.
526.9.1 states "in order to avoid inappropriate seperation or spreading of individual wires of multi wire, fine wire or very fine wire conductors, suitable terminals shall be used or the conductor ends should be suitably treated."
526.9.2 states "soldering (tinning) of the whole conductor end of multi wire, fine wire and very fine wire conductors is not permitted if screw terminals are used. "

I've always twisted and doubled over; C&G 2365 say this is okay. But you must be careful of not over tightening in case you damage the fine wires. Although the more I think about it I will probably treat myself to some quality Hez crimpers.

So we know we can use "suitable terminals", (assume crimping), but can't tin; so otherwise what else is "suitably treated" ?

if your using very fine wire, im thinking tri-rated not 6491b btw.
then it needs ferrule crimps or at lease ferrule sleeves without the plastic cap

HandySparks · Aug 2, 2015

Michaelwgroves said:
I've just been reading the IET requirements for electrical installations 17th edition.
526.9.1 states "in order to avoid inappropriate seperation or spreading of individual wires of multi wire, fine wire or very fine wire conductors, suitable terminals shall be used or the conductor ends should be suitably treated."
526.9.2 states "soldering (tinning) of the whole conductor end of multi wire, fine wire and very fine wire conductors is not permitted if screw terminals are used. "
...
So we know we can use "suitable terminals", (assume crimping), but can't tin; so otherwise what else is "suitably treated" ?

I assume this would include just tinning the tips of the strands, as done by some manufacturers to flexible cables fitted to appliances and luminaires. Also a compression/welding treatment as used on flexible cables pre-installed in consumer units and on RCBO neutral tails.