Copper wire for PCB traces issues. - Page 1
Forum section: electronics / beginners

author: davelectronic
author_rank: Frequent Contributor
timestamp: June 07, 2021, 11:34:26 am
content: Recently I have been trying to increase current carrying ability on copper stripboard. I've successfully got to 12 Amps at 12 Volts, but was needing to go to about 20 Amps or even 30 Amps. Problems I've encountered is warping of the copper stripboard, quite badly. I assume it's heat build up and the solid copper wire expanding and contracting. It gets quite tough soldering 2mm copper wire, and the board size is 100mm X 160mm. It's the FR4 gold plated stripboard, as a though it would be more rugged in use. I'm just wandering what would be the minimum copper wire size in short lengths ( less than 100mm in most cases) As link up wire to achieve 20Amps or even 30 Amps. It feels compounding by limitations of link up wire size. The circuits for this are the typical linear voltage regulators, with multiple series parallel pass transistors for the current carrying ability. I guess 1mm copper wire with added solder to its length is not sufficient for as much as 20 Amps to 30Amps. Would copper strip material, say 5 mm to 10mm and a thickness of say 0.5mm to 1mm be more practical ? I would really appreciate your thoughts on this problem. And thank you for reading.

author: Ian.M
author_rank: Super Contributor
timestamp: June 07, 2021, 12:16:35 pm
content: 20A on stripboard is madness. That's heavy copper wide track PCB territorySeehttps://electronics.stackexchange.com/questions/223702/what-is-the-current-carrying-capacity-of-a-single-stripboard-trackIf you cant redesign to keep the high currents off the stripboard, e.g. by doing the high current wiring point-to-point on tagstrip, you'll need heavy copper sheet reinforcement carefully cut to shape, and sweated onto the stripboard, before drilling for component leads and terminals.Helpful links:https://basiccopper.com/thicknessguide.htmlhttps://www.desmith.net/NMdS/Electronics/TraceWidth.html

author: fourfathom
author_rank: Super Contributor
timestamp: June 07, 2021, 02:50:38 pm
content: You might consider something like this:https://www.te.com/usa-en/product-1SNK910302R0000.htmlThere are many variations, this is just the first one I found.

author: davelectronic
author_rank: Frequent Contributor
timestamp: June 07, 2021, 06:13:55 pm
content: Thanks for your replies, I knew copper stripboard wasn't meant for much more than 1 to 2Amps. I have been twisting 1mm solid copper wire, so 2mm overall. But it's warped the FR4 GRP board, it was never intended for heavy wiring, I know that now. I'm not sure what those orange jumper looking things are, I had thought about the Manhattan style of PCB, like they use in the US for the heavy duty linear amplifiers. Point to point wouldn't be to bad, but I still need some type of board to physically mount components to. So perhaps a plain GRP type board, but the Manhattan style does have a lot of appeal to it, but I don't think the heaviest copper clad board could carry up to 30 Amps at 12 Volts. Have to do a bit of looking online to see what I can find.

author: bobbydazzler
author_rank: Regular Contributor
timestamp: June 07, 2021, 06:25:53 pm
content: Can't you just solder some thick insulted cooper wire at each end of the copper strip(I guess it doesn't need to be insulated) Then it shouldn't be warped from all the heat.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: June 07, 2021, 07:19:02 pm
content: Can pre-bend the board the right amount, so it bends back on cooling.Or make a zigzag path, so it's more flexible; takes up more space, and adds a bit of resistance.Or use sheet/foil, so it's not as thick (less bending moment). Needs to be wider of course. Gives low inductance.Or wire it point-to-point like in the old days, which seems practical given you have a bunch of power transistors on a heatsink, right? Put the control stuff on board, make some brackets to mount the board to the heatsink, fill in the rest.Tim

author: fourfathom
author_rank: Super Contributor
timestamp: June 07, 2021, 07:30:17 pm
content: Quote from: davelectronic on June 07, 2021, 06:13:55 pmThat's why I included the link to the mfg page, which included the data sheet.But these are busbars with pins, so you can solder them into a PCB.

author: Alti
author_rank: Frequent Contributor
timestamp: June 07, 2021, 09:30:11 pm
content: Thick jumpers are perfectly fine, just use stranded wires, preferably with crimped terminators to avoid capillary force sucking tin inside. If you want to use solid core then you have to make these longer, instead of simple I, you need C or S shape or perhaps add compensating loops.

author: davelectronic
author_rank: Frequent Contributor
timestamp: June 08, 2021, 03:45:28 pm
content: Thanks for explaining those terminations, push and pull with regard to warping is probably hit and miss if I'm lucky. Just ordered some 2mm solid copper wire, I'm going to give it one more go with stripboard. But all high current paths double up the 2mm wire. To try and avoid warping, I'm going to tack the copper wire to the FR4 plated tracks. Hopefully tacking should minimise heat in the board, and prevent warping. If it fails, I will try point to point, using Manhattan style PCB techniques. Watched a few linear HF amplifier builds on YouTube, looks ok as a method. Those US amplifier build whopping great big amplifiers, drawing rediculous amounts of current and power, so that technique could in theory work for high current power supply use. I've got silicone sheathed wire in 18 , 16, and 14 AWG, and some 12 AWG for input output cables. I took a close look over one of the AWG charts for wire use limits, so difference between chassis wiring, and transmission line ratings. Hopefully I can work something out that can handle current between 20 Amps and 30 Amps at 12 Volts to 13.80 Volts.

author: Ian.M
author_rank: Super Contributor
timestamp: June 08, 2021, 04:56:51 pm
content: *IF* you aren't doing high frequency RF or switching PSU stuff, I'd go with tag-strip with terminals on both sides mounted on short standoffs to the same heatsink as the power transistors. You can splay the leads of a TO220 enough to go straight to the tag-strip, and put the point to point wiring on the other side. If you need to mount power resistors (not the preferred heatsinkable bolt-down type), put a second tag-strip parallel to the first separated by the resistor body length + 1/2", and mount the resistors between them. You can keep low current control circuits on the stripboard.https://www.ebay.com/itm/283190620464looks suitable.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: June 08, 2021, 09:26:48 pm
content: I wouldn't bother doubling that up, that's pretty stout wire and you're not doing house wiring. Chassis wiring can be rated much higher.Tim

author: davelectronic
author_rank: Frequent Contributor
timestamp: June 09, 2021, 12:33:49 pm
content: I have come across barrier terminals on eBay, a seller of ONS (old new stock) has them, but these are screw type open terminals. I would have thought 2mm wire across a 100mm X 160mm board would be sufficient for 20 Amps at 12 Volts, and maybe a bit more. I still have this erge to try Manhattan style PCB building, it just looks functional and a solid technique to use. I've got 9m of 2mm solid copper wire on its way now. Probably way to much, but for the future...I'm not at the SMPS build just yet, that's a dounting project as it's far more complex, I know my limits, and just now that would exceed my abilities. I've just got my first permanent use linear PSU working, it's been running about a week now 24/7 I don't turn my radios off at all. That one is 12 Amps at 12 Volts, but I'm not going to pull much more than 8 Amps from it. I have three other variations of the same cases (they where cheap) three cases are doubled up for more flexibility. Hopefully the other projects will turn out ok.

author: bobbydazzler
author_rank: Regular Contributor
timestamp: June 09, 2021, 11:07:52 pm
content: Stripboard seems to handle a bit over 3amps before the Temp of the stripboard starts to rise(resistance increases with temperature and you don't see the output current dipping until it's fed with over 3 amps and even then it's small)https://youtu.be/WT9xWyLK-Ic?t=2512mm copper wire should be heaps.

author: davelectronic
author_rank: Frequent Contributor
timestamp: June 11, 2021, 03:33:31 pm
content: I've only ever used Vero board, or copper stripboard. Normally I can solder the tracks with just solder to get more current, this doesn't warp the board. But the addition of 1mm X 2 twisted copper wire does warp the board. Problem with just solder for higher current is maintaining an even solder track, and I have gone up to 12 Amps at 12 Volts using just solder, but that used two tracks to carry the current. It uses loads of solder doing it that way though. I've got 9 meters of 2mm solid copper wire, my word it's looks well heavy duty. The more I look at the Manhattan techniques, the more appealing it's become, I can cut the island pads, and link up with insulated wire. Or solid copper with added heat shrink tube, I can se that method carrying very large currents if link ups between island pads is suitable heavy gauge wire. Something about this technique looks like it will just work. The youtuber Mr bbi builds high powered linear amplifiers, and these use whopping amounts of current. Ok it's not as precision looking at an etched PCB, but surely it makes up for that in heavy duty functionality. I've orded some single sided copper clad board, on reflection, I should have ordered double sided copper clad board, as I could of expanded to the underside if I needed. If it works out well, I will opt for the double sided board next time.