0
\$\begingroup\$

I want to use a relay to control some 230VAC equipment, by doing so i want to toggle the live wire.

Is there a standard/safe method to do this in terms of the components to use, or is it a matter of cutting into the outer sleeve, then cutting the live wire, and inserting them into some screw in terminals like this which then connect to the relay?

Edit: Of course the wire will be not live when I'm working on it.

\$\endgroup\$
  • \$\begingroup\$ @AndrewMorton I have added clarification. I'd not go to the internet to ask how to work on live wire when it's live. I can understand how you came to that conclusion though - I mean the live wire of a three pin plug, not a wire that is live. \$\endgroup\$ – Orbitronics Oct 3 '17 at 12:43
  • 1
    \$\begingroup\$ Do you have a choice of the relay? You can get them with 4 mm terminals which accept spade connectors. The spade connector (with appropriate insulation) is easily crimped onto the wire with the correct tool. \$\endgroup\$ – Andrew Morton Oct 3 '17 at 12:44
  • 1
    \$\begingroup\$ @Orbitronics You would be distressed at some of the questions that get asked here... \$\endgroup\$ – Andrew Morton Oct 3 '17 at 12:45
  • 1
    \$\begingroup\$ @Orbitronics perhaps editing the title to something like "splice a wire meant for mains voltages" such that there is no room for misinterpretation? And no worries, I can totally understand your response. It's just that some of the people ask questions like that and genuinly mean working while circuits are live. \$\endgroup\$ – Joren Vaes Oct 3 '17 at 12:49
  • 1
    \$\begingroup\$ @JorenVaes Thanks, I went ahead with the edit. I genuinely wonder how more people haven't died from touching the live wire. \$\endgroup\$ – Orbitronics Oct 3 '17 at 12:53
4
\$\begingroup\$

The best way to do this type of wiring would be using crimp connections such as spade lugs or quick-connect lugs, making sure everything uses the male counterpart.

They come in various shapes and sizes. For mains, I would suggest getting the shielded type. (Picture shows unshielded version so it's clearer what type I'm talking about) enter image description here

You need the right type of tool to crimp these in.

\$\endgroup\$
  • \$\begingroup\$ Thanks, then I think I need to purchase these: goo.gl/Cwf67e And thanks to you and Andrew I learnt that i should use spade connectors in general. If I wanted to use the existing THT relay I have, as shown here: goo.gl/UsW8xu Would it be unsafe to do the following: goo.gl/3kz5mj Note the small red lines I added. I'm sure if i did that, it'd be much safer if i crimped the wire before placing them in the screw-in terminal. \$\endgroup\$ – Orbitronics Oct 3 '17 at 13:07
  • 1
    \$\begingroup\$ You should get these connectors with insulation over the spade part as well, but if you can't you can heatshrink over the top. You can also tether the wires to prevent a single broken connection from contacting anything else, whether that's dodgy crimping, a snapped-off pin or whatever. \$\endgroup\$ – Chris H Oct 3 '17 at 15:22
0
\$\begingroup\$

Safely and legally are not necessarily the same thing.

A lot depends on where you plan on splicing. If this is intended for splicing into the mains wiring of a facility or home the requirements will be significantly different to say splicing into the cheapo zipper cable that's attached to your table lamp. Further, depending on where you live, codes may differ.

The crimped spade connectors indicated in Joren's answer are probably the handiest to work with, but do suffer from installation issues if you are not using the right tools or the right kinds and diameter of wires. I have seen the wire come out of those too many times.

If it's for splicing into single core mains cable, push in connectors are acceptable and available in some regions, "wire nuts" are widely used in North America, but ultimately, you can't beat screw down connectors.

A bigger issue though is enclosing all that, possibly in a grounded "box", and including sufficient strain relief and or clamping to ensure no tension or twisting forces on the cable can be transferred to your connection.

\$\endgroup\$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.