Inaccessible junction box / electrical crimping tools

[Dave Plowman (News)]

You'd use a butt joint to solder cables together?

[The Medway Handyman]

I find them all the time as well.

[The Medway Handyman]

too.http://www.tlc-direct.co.uk/Main_Index/Cable_Accessories_Index/Wago/i...>>>> The 773 push-wire, or the 222 lever connectors?

I use the grey 101's (1 solid to 1 flex) and the white 112's (2 solid to

1 flex) for the switch live & neutrals.

[Dave Liquorice]

Not a red plastic wall plug, stuffed over twisted together wires and then taped up? Poor quality tape the adhesive had become soft and the tape was starting to fall off. Found that here.

[Andrew Gabriel]

I have used ordinary junction boxes with screwed terminals as normal, and then soldered the terminals afterwards. However, unless you are very expert at soldering, I wouldn't recommend you do this as you could easily create dry joints unknowingly.

Crimping using a ratchet crimper and the right sized crimps is likely to be much more reliable in unskilled hands.

I have an old book on working with copper tube. If you take a standard soldered joint and apply enough force to pull it apart, the copper tube breaks somewhere other than at the joint, as if soldered properly, the joint is stronger than the bare tubing.

[Dave Plowman (News)]

I've a feeling the solder used for pipework is stronger than electronic solder.

If I were soldering mains cable. I'd twist the connectors first. That would provide a fair degree of mechanical strength even before it is soldered.

[John Williamson]

No, it's more or less the same alloy. The extra strength relative to the materials being joined when soldering pipework comes from the much greater joint area and the relative thin-ness of the pipe on domestic plumbing. Tens of square millimetres of solder in shear rather than square millimetres in tension. Solder joints are also stronger in shear than they are in tension. Either way, the thinner the solder film, the stronger the joint.

[tony sayer]

Used these for years for a lot of applications and never once a problem but you must spend on a decent pair of ratchet crimpers, not that abortion with Two bits of pressed flat metal!...

[Lobster]

Is crimping a repair and burying it in plaster actually totally kosher?

Just asking because after my brush with a broken ring main a few months ago (see my posts passim!), which I eventually was forced into getting a sparks in to sort out, he located a broken, buried cable half way down a wall... at one point it looked like the house might have needed to be half-demolished to access the ends of said cable in order to replace it, and I asked whether he couldn't crimp in a new bit. He was adamant that he wouldn't.

Ultimately he managed to circumvent the problem by pulling a new length of cable through the capping (phew!) and I didn't need to press the issue - but just wondering?

David

[John Rumm]

It meets the regs requirement for an inaccessible joint. That does not mean that its better than not having a joint at all, or for that matter that all practitioners will be keen to use it.

If done properly, then the crimp should be equally capable of carrying the full circuit current, and should be adequately insulated to prevent degradation of the joint with time.

[<me9]

We once had problems with large crimps(>100mm^2), which were a size too large for the cable. This caused the cable to stretch and work harden and fail after a year or two. If the correct size had been used there would have been no problem.

The equipment fed rom this supply also had problems. The wrong flux(acid) had been used on soldered lugs and not washed off, leading to corrosion causing failure particularly on the smaller sizes.

Altogether a bad batch!