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I often use screw terminals like the below for semi-temporary setups (e.g. in the lab) enter image description here

However, I often need to connect three wires together, so what I've been ending up doing is squashing two wires into one side of the connector and one into the otherside. But this doesn't seem like the best way to do it - what should I be doing here?

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    \$\begingroup\$ There's nothing wrong with doing it that way. Another alternative, especially with thick wires, would be to put the 3 wires into the 3 terminals on the left, then connect the 3 terminal together using wire on the right terminals. \$\endgroup\$
    – Steve G
    Jun 27 '18 at 9:27
  • \$\begingroup\$ Even UL allows 2 wires per terminal :) \$\endgroup\$
    – MadHatter
    Feb 8 '19 at 3:25
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You can get Terminal Blocks - Barrier Blocks that have screw terminals that allow 3 wires on one side, and then use a jumper to connect the 3 on the other side to connect to 1 wire

https://www.digikey.com/products/en/connectors-interconnects/terminal-blocks-barrier-blocks/368?k=terminal%20block

This one has 4 screws, shorted across the barrier, for example.
https://www.digikey.com/product-detail/en/molex/0387700104/WM5761-ND/362488

enter image description here

You can also get jumpers to connect screws together.

https://www.digikey.com/products/en/connectors-interconnects/terminal-blocks-accessories-jumpers/385?k=barrier%20block%20jumper

Here's one example

enter image description here

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Putting multiple wires into one side of a connector is what everybody does.

It does mean that it can be a bit tricky to get all the wires pushed in at the same time to the right depth.

With stranded wires, there are rarely any problems. Twisting them together before pushing them in can help with alignment.

With solid wires, there can be configurations of 'a few' wires that leave one of the wires not properly clamped, if the others form a stable arrangement and take the screw clamping force like an arch. Be aware of that as a failure mechanism to look out for.

If you really want a one-wire-per-screw arrangement, then you could permanently wire a link along the 'backs' of several connectors, and use one wire each to the front.

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  • \$\begingroup\$ Oh yes - that one loose wire... \$\endgroup\$
    – Solar Mike
    Jun 27 '18 at 9:40
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I suppose the question is subjective to what the best is, but imho the accepted previously accepted answer is ridiculously expensive.

The latest accepted answer, screwing terminals, screwing wires under screw heads I've always found tedious to use. And don't see much of a difference between those screw terminals and the screw terminals in the OP question

(I know my opinion belongs in a comment but I don't have the points)

The simplest thus I consider best answer is simple twist on Wire Nuts. They come in all different sizes and are the cheapest and arguably the quickest solution for a "temporary setup"

wire nuts

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    \$\begingroup\$ I agree these "terminal" are prohibitively expensive. And I assume the OP refered to the type of connector on the picture. \$\endgroup\$
    – Fredled
    Feb 7 '19 at 9:32
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But this doesn't seem like the best way to do it - what should I be doing here?

It isn't the best way. The correct way is to terminal blocks. These can often be linked with jumpers. For example, these push-in variants from phoenix (no screws).
phoenix push-in terminal blocks

If these fancy terminal blocks are too expensive, which they often are, then normal screw ones can be used as well. With twin ferrules for example.

twin ferrules

Three in one clamp is generally avoided. But for temporary setups it can work just fine.

For quick setups I can recommend these units (Wago 222), they support solid and stranded wire, and are easy to connect/disconnect. Readily available at your local hardware shop, and not expensive.
wago 222

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You can probably get by with just twisting the wires together and stuffing it in the screw terminal. If you want to do it properly: use ferrules. You can twist the two wires together and put a twin wire ferrules over it, then place it in the screw terminal. Do the same with the single wire and a regular ferrule on the other side of the screw terminal.

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With the type of connector from the picture, you can usualy put two (more if the wires are small gauge and the connector is large enough) solid wires into the same hole. You must twist them together. Ferules are useful only on multi strand wires. Do not use them on solid monolithic wires. It's good put some solder on wires twisted together. Waggo types are good only if all the wires have the same gauge. Otherwise there is a risk the smallest one won't hold.

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