Crimping Cable

[JMS]

I am considering moving a 13A socket higher up and will need to extend the current single spur cable.

Some questions re crimping:

I know that one should use a very good quality crimper.

I have seen instructions where it says crimp one cable first - using half of the crimp - then insert the other half and crimp that; others say put both cables in and just crimp once.

Is it better to use a larger crimp and have the cables inside the crimp over-lapping - or the smallest suitable where the ends butt up inside the crimp?

I have experimented and having cables inside the crimp over-lapping and crimping both cables at the same time seems favourite - but is it?

Views?

(I have Googled and looked at some pages - but any link to particular good references appreciated)

[Andy Dingley]

"Good"quality is adequate. Once you're away from the pressed sheet and have a crimper with a ratchet, then you're fine.

Whichever. But put the individual wire ends into their own crimp, not sharing.

[Roger Mills]

Maybe it depends on the crimp. The ones I'm currently using have a stop in the middle - so the cables *cannot* overlap, and you *have* to crimp each one separately.

[John Rumm]

Something with a ratchet is what you need. They are not that expensive these days.

Most of the butt splice connectors need two crimp actions - one on each end, since they have a stop in the middle.

Personally I always crimp each end separately. The crimp tool only compresses about a 5mm wide bit of crimp - which works out about right on the connectors I use - leaving a bit of insulation un-crimped at the end.

Try this:

[JMS]

Would you recommend them - from where please if so.

[Dave Plowman (News)]

A lever action ratchet type should be fine - you don't have to pay a fortune for these.

All the tools I've seen are for one side only.

A normal pre-insulated butt connector has a division in the middle so you can't overlap the cables.

Where did you get those connectors?

[JMS]

Maplin

[Dave Osborne]

Standard ratchet crimper, e.g.

you want to go for a branded product, then Davico DHCR15 is OK

Which is normal for insulated butt-splices.

others

Not sure what sort of crimp you're alluding to.

Not overlapping.

The main thing is to make sure that the crimps and the tool match.

B&Q sell (presumably Chinese made) crimps which are smaller than standard and do *not* crimp properly with a "standard" Davico crimp tool. You must always do a "tug test" after crimping to ensure that you can't just pull the wire out of the crimp.

Try to avoid Chinese-made "assortment boxes".

Buy crimp lugs from a reputable supplier, such as TLC, Farnell, RS, CPC, Rapid Online or your friendly local electrical wholesaler.

[JMS]

excellent responses - many thanks to those who did

[chris French]

In message , JMS writes

Yup, the ones I have are like that. Mine came from Screwfix a few years a go. As did the ratchet crimper. It wasn't that expensive and does the job fine

[Dave Plowman (News)]

Best to get them from an electrical wholesaler like TLC, etc. They are of a uniform quality. I've seen some pretty crappy ones on sale at markets, etc. But dunno Maplin ones. If they're sold as an assortment they're more likely to be of poor quality.

[Spamlet]

Notwithstanding the good advice about crimping. Wire being pretty cheap, I would, if possible, simply run a longer piece through. Don't trust crimps, especially in car/bike electrics, where they really are a pain when you want to move anything... Spose I'm just old fashioned but they always look like a bodge to me.

S

[Dave Plowman (News)]

Those pre-insulated terminals often are in cars, etc. But the original terminals are crimped. It's only a question of using the correct ones with the correct tool to crimp them. Vehicle wiring products are a good source of both.

[JMS]

Good - I bought the ratchet crimper from Screwfix - but (may have) made the mistake of buying crimps from Maplin.

I did not want the big box at 20 quid plus of crimps from Screwfix (I thought that there would be many I would never use - spade ends etc) - but I think I will buy a selection of their smaller packets.

I have looked at mine again - the yellow ones have a internal lug in the centre so that both cables will butt up to it - but the red and blues don't have. Do the Screwfix red and blues have them?

[Dave Plowman (News)]

Dunno about Screwfix, but the ones I bought from TLC do. It's not a complete dead end, though - just designed to stop cables of the correct size going beyond half way. Obviously so it can compress when crimped. It looks a bit like a triangle outline.

I've seen so many poor connections with these pre-insulated terminals - whether down to the terminal itself or the crimper - I only use ones from a reputable source. Like an electrical wholesaler.

[Spamlet]

Anything wrong with just soldering?

(Also, thinking of that. We used to have some really thick plastic gloop that we could even dip bus bars in to insulate them. But waiting for it to dry would be slower than crimps.)

S

[Andrew Gabriel]

It's a more skilled job than crimping, but if you are competent at soldering, that's fine (and you'll know that you need something other than just solder to take the mechanical stress, etc).

[sm_jamieson]

So you may as well crimp for the mechanics, and then solder for good measure. I've just ordered some crimps and a ratchet crimper from TLC, to replace some choc blocks and insulating tape where I extended some wires for the new CU. If crimping 3 wires of TWE, do you need to wrap the whole lot in anything or just leave the crimps in thin air ? Simon.

[John Rumm]

Unless inside an enclosure (say in the CU) then you will need an outer insulation as well. Heatshrink is probably easiest:

[Spamlet]

--

Soldering wire easy peasy (except with that nasty lead free stuff). Would have thought this was stronger than crimps - unless all the crimps I've had to deal with have been done by people with very limp wrists. Soldering pipes not so confident.

Used to do solderability tests once upon a time. Standard little bead of solder on a little hot plate, then swing piece of clean wire down into bead and measure how long it takes to close around the wire. Does not come off in a hurry if done properly.

S