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I have about 40 positive and 40 negative 18 gauge wires that I am trying to connect to one DC power source.

I have a few terminal blocks to achieve this. Each terminal block has 2 rows of 12 positions and I am trying to minimize the number of terminal blocks I use to wire everything together.

Below is a photo of the type of set up I am going for. My concern, however, is that stuffing too many wires into a single terminal hole is probably an unsafe practice. Is there a best practice for how many wires I can safely stuff into terminal block screw holes? I know the wires must not be tinned but is the number of wires I can fit into a terminal block hole affected by whether the wires are stranded or solid (I have both and wonder which is preferred)?

Also if anyone has a better way to wire these connections together I'm all ears, I feel like there must be a better way of doing this...

enter image description here

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    \$\begingroup\$ @Passerby I ordered them off Alibaba and they didn't come with a datasheet unfortunately \$\endgroup\$ – Matt Aug 10 '18 at 18:54
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    \$\begingroup\$ If you are concerned about reliability or safety, never buy something that comes without a datasheet. \$\endgroup\$ – Elliot Alderson Aug 10 '18 at 19:07
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    \$\begingroup\$ IMO, you are using the wrong type of product. Use Barrier Strips with matching jumper strips instead. That will allow the use of crimp style spade terminals for the 18 gauge wires. You can typically get 3-4 18 gauge wires into one Spade terminal for 18-14 gauge wires. \$\endgroup\$ – Norm Aug 10 '18 at 19:15
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    \$\begingroup\$ Stranded wire is better for crimp terminals if you're not soldering. I would suggest first checking out "Terminal block bus bar"s. They are simply a busbar, pre-mounted on an insulator and pre-tapped and screws provided for a number of connections. I would suggest "fanning out" the connections as well. Use the largest wire allowed to attach the DC supply to the center of the first bus bar, and large wires off of those bus bars to feed the centers of the necessary number of bars to connect all of your 18 guage wire. This will ensure they receive more balanced current. \$\endgroup\$ – K H Aug 10 '18 at 22:40
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    \$\begingroup\$ As for the terminal blocks you have, if you can figure out what material they are at least, and you find the measurements of the thinnest part of the connection, calculate it's cross sectional area and now you know what size of conductor you can consider that terminal block to be. The only question other than that is how many conductors it can effectively mechanically secure, and in practice, that typically amounts to what will fit in the hole and still allow the screw to be done up to rated torque (you don't have a datasheet, so you can use the rated torque of a screw of it's type. \$\endgroup\$ – K H Aug 10 '18 at 22:50
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You'll spend a little more, but use DIN rail mounted modular terminal blocks with jumper bars and you'll have a much nicer setup.

enter image description here

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  • \$\begingroup\$ A DIN rail setup might be bigger than the power supply. \$\endgroup\$ – D Duck Aug 11 '18 at 1:02
  • \$\begingroup\$ Yeah this seems like a bit overkill, I think a simple busbar will do the trick after reading the other comments. Thanks for the suggestion though! \$\endgroup\$ – Matt Aug 11 '18 at 4:47
  • \$\begingroup\$ @DDuck - Have you ever used these? With standard 5mm terminal blocks, you'd be under 6" overall. With the high density blocks with three terminals on each side, you'd be around 2" long. No doubling up. \$\endgroup\$ – batsplatsterson Aug 11 '18 at 11:55
  • \$\begingroup\$ @Matt a busbar would certainly work but terminal blocks are very flexible, easy to expand or shrink, make very secure connections without crimp on terminals on the wires. Once you use them you'll never go back. \$\endgroup\$ – batsplatsterson Aug 11 '18 at 11:58
  • \$\begingroup\$ @batsplatsterson The power supply (5-50-5 ie a 5 V 50 W supply for driving LEDs) in the photo is about 158 x 98 x 42mm, but the DIN terminals you're suggesting is about the same volume. It's obviously much bigger than the terminal strip on the power supply itself. Why not use a strip like the one on the power supply? \$\endgroup\$ – D Duck Aug 11 '18 at 16:01

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