Wiring multiple power supplies to one plug - Page 1
Forum section: electronics / beginners

author: StefanS
author_rank: Newbie
timestamp: December 21, 2021, 10:26:11 pm
content: Hi Folks,This may seem obvious, but I want to be safe. I have three SMPS (two wired in series for +/-12V, and one 24V). I’d like to use one plug for all three. Would I use three terminal strips (one for hot, neutral, and ground)? Or, is there a better way to get the AC to the supplies? Ultimately, I’ll switch to a power supply with multiple voltages.Thanks,Stefan

author: IanB
author_rank: Super Contributor
timestamp: December 21, 2021, 10:30:42 pm
content: The best way to get the AC to the supplies is to use a standard AC power cord, one cord for each. If you have three supplies, use a switched power strip, then you can turn them all off and on at the same time.

author: Ian.M
author_rank: Super Contributor
timestamp: December 21, 2021, 10:42:09 pm
content: It depends on the AC power in connections of the power supplies. If they are terminal strips for ring terminals, wiring them in parallel is easy. If they are terminal blocks, its a little harder. If they have permanently attached cables or IEC connectors its a *LOT* harder . . .

author: themadhippy
author_rank: Super Contributor
timestamp: December 21, 2021, 11:26:40 pm
content: Quotemultiple iec is dead simple,at least here in the uk were we we can buy things like this.

author: StefanS
author_rank: Newbie
timestamp: December 22, 2021, 01:32:13 am
content: Good point, Ian. These are Mean Well supplies, so they would use small spade connectors. Thanks for the responses, guys.

author: Ian.M
author_rank: Super Contributor
timestamp: December 22, 2021, 03:52:09 am
content: 1/4" or smaller?

author: StefanS
author_rank: Newbie
timestamp: December 22, 2021, 03:51:02 pm
content: A little smaller. About 5mm.

author: Ian.M
author_rank: Super Contributor
timestamp: December 22, 2021, 06:55:25 pm
content: Ugh! Although it is *possible* to make up a daisy-chain cable with crimp terminals, I doubt you'll find it easy to get either large enough ones to accept two cores of adequately rated mains flex, or stacking M & F spades the right size, and its always a problem ensuring the daisy-chain connection insulation is adequate for mains use.Presumably all three are going in an enclosure. If so, fit an IEC 60320 C14 mains inlet, (optionally with fuse and/or mains switch) with solder lug terminals, solder the wiring for all three PSUs to the terminals and insulate each terminal and reinforce the connection with adhesive lined heatshrink, and aso fit a C14 inlet rubber boot.If it doesn't have an enclosure you are living dangerously unless the PSUs have fully enclosed supply terminals with provision for a cord grip, and the best option would be to use bus bars for ring or fork terminals, e.g.https://www.amazon.com/Terminal-Circuit-Positions-Insulated-Electrical/dp/B08P46WVJX/for Line, Neutral and Groundinside a large enough glanded junction box.You could also butcher an IEC C14 to 3x C13 splitter cable, cutting off the C13 connectors and replacing them with your female spade connectors. I'd wire one of the ground wires to a ring terminal to ground your chassis with a daisychained spade connecter for that PSU's ground. Don't forget to adequately secure the trailing C14 connector to the chassis.

author: StefanS
author_rank: Newbie
timestamp: December 23, 2021, 02:03:19 am
content: Thanks Ian. Rest assured that it will be switched and fused. It is for a video game arcade machine (scratch built), so it requires different voltages for the tube, video amp, and processor. All the elements will be fixed in place and inaccessible to the user. I just didn’t want multiple power cords coming out of the case.

author: james_s
author_rank: Super Contributor
timestamp: December 23, 2021, 05:34:57 am
content: If the power supplies are all integrated into something like that then just make a custom wiring harness to supply power to them. A terminal block is fine, or you can daisy chain from one to another, or any number of other methods.