Widget for joining 3-core mains flex

I didn't see the beginning of this thread, but a technique that I frequently use when joining wires is as follows. Look at the diagrams in Courier New font, or they won't make much sense.

--------------

------------------- Cable +---- wire_1 --------------------+ Cable sheath +----------- wire_2 -------------+ sheath +-------------------- wire_3 ----+

--------------

---------------------

Firstly, strip a piece of the outer cable sheath off and put it to one side to use later. Then cut the wires as shown in the diagram. Bare the ends of the wires, and solder the two ends of wire_1 together, and the same for the other wires. Because the wires were cut to different lengths in this way, the soldered joints are not close to each other, and cannot short together.

Now take the piece of sheath that you put to one side, slit it down the side, and put it over the new joints. At this point, the cable should look almost as if it had never been worked on.

-------------- -------------------------------------------------

------------------- Cable | This is the piece of sheath that you | Cable sheath | kept to one side, now used to | sheath | cover the joint |

-------------- -------------------------------------------------

---------------------

Now wind some electrician's tape around the full length of the sheath that you have inserted, and an inch or so beyond each end. Better still would be if you had slipped a piece of heat-shrink tubing over the wire before soldering it together. The heat-shrink tubing should be about two inches longer than the piece of sheathing you used to cover the joints. _________________________________________________________________

---------/ / / / / / / /----------- / / / Taped up with electrician's tape / / ----/ / / / / / /____ / / / / / / / /

----------/_________________________________________________________________/------------

I have used the same technique on multi-wire cable - most recently on an Ethernet cable that I had to cut to get through a small hole, then join together again, because I didn't have the tool to put the connector back on. In this case, with 8 wires, the total length of the connection was about 4 inches.

MikeC

-------------------

---------------------

----------/_________________________________________________________________/------------

Fine for signal cables.

Lethal for mains flex.

The method provides virtually no strain relief for the conductors. Which a continuous outer sheath provides as well as insulation.

Subject to even a modest pull, the conductors or soldered joints will fail, potentially leading to a bare live conductor.

Any means of jointing mains flex has to provide strain relief for the conductors comparable to that provided by the outer sheath of the original cable.

It would also be ok for fixed house wiring in the uk, although heatshrink would be a more appropriate sleeving material than insulating tape.

Yup. If you had some form of enclosure with cord clamps though then it would be fine.

You're thinking of the Western Union splice: