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I am looking for a cable standard to control and power a device from its controller.

I need to send 5V/10A but also control (not sure yet what protocol it could be but I don't need a high speed, 9600b serial could be enough) over short distance (about 2m.) I looked up PoE but it's really not enough in terms of power. Ideally I don't want something too exotic and hard to find.

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    \$\begingroup\$ Digikey has a large selection Link is that not what you are looking for? \$\endgroup\$
    – Tyler
    Aug 16 '21 at 15:50
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    \$\begingroup\$ Seems like PoE type 3 can deliver 51 Watts to the load. With an efficient buck, you can just about get 10 A at 5V. PoE type 4 can deliver 73 Watts to the load which seems ample. These versions of PoE are new-ish at the moment and I don't have experience with them. I am just calling it to your attention. \$\endgroup\$
    – mkeith
    Aug 16 '21 at 16:23
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    \$\begingroup\$ @Fred Digikey also offers a wide selection of connectors for multi-conductor cables... \$\endgroup\$
    – Tyler
    Aug 16 '21 at 17:10
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    \$\begingroup\$ 5v is a bad/expensive way to send 50w. If you're making one thing, just use buck regulator module at the device end of the cable and feed it 24 volts instead of 5 from the supply end. \$\endgroup\$
    – dandavis
    Aug 16 '21 at 23:48
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    \$\begingroup\$ Use ethernet over power cable adapters. Very handy, good bandwidth, very high power on 2 conductors: netgear.com/au/home/wired/powerline/plp2000 (NetGear is just an example, plenty such products around). \$\endgroup\$
    – oakad
    Aug 17 '21 at 8:22
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USB Type C, properly configured, can provide up to 100W and also a means to connect a serial device using the basic DP/DM pair.

More here: How does a USB C port provide the power to charge laptops?

The reason PoE limits the power has to do with the magnetics: the core wires are quite small, smaller than then 24AWG that Cat5 uses, which can carry up to 2A or so per wire.

As it so happens, PoE has seen some upgrades and can now support up to 90W. More here: https://www.versatek.com/what-is-power-over-ethernet/

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  • \$\begingroup\$ Looks like a nice idea, but it seems a bit complicated for me, I m new in electronics and I wanted to have just one transformer 220v to 5v so that i could power the controller and the device. From what i understand reading the specs i would need to be able to deliver multiple power range then transform it again (both for logic and for the device as they use 5v)? \$\endgroup\$
    – Fred
    Aug 16 '21 at 15:29
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    \$\begingroup\$ @Fred this is an electronics design oriented forum. So a lot of times we assume people are looking to design something or at least that they are open to implementing an electronic design. You could definitely just use a cable with two heavy conductors for power and three smaller ones for serial and call it a day. Just make sure you go through the calculations for voltage drop in the cable. This is kind of a 1970's solution not a 2020's solution but it worked then and it will work now as long as you don't mind a bulky shielded cable (I do recommend the shield). \$\endgroup\$
    – mkeith
    Aug 16 '21 at 16:28
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    \$\begingroup\$ You asked for a 'cable standard' that could support a ~2m run and 50W of power. I offered you two solutions. Of course you could make something bespoke using a multi-pair cable. For that kind of a run however I'd recommend at least 12V, and preferably as high as 20V, to reduce losses. \$\endgroup\$ Aug 16 '21 at 16:48
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    \$\begingroup\$ I didn't consider the loss of power, and 20v is the way to go. The usb solution is elegant but I cant find a breakout board for type 5, all i could find was 5v/1.5A. For POE the breakout board STEVAL-POE001V1 is at 50 euros... Maybe the "1970's" solution would be the simplest in my case. Thanks you both for the very pertinent suggestions \$\endgroup\$
    – Fred
    Aug 16 '21 at 21:49
  • \$\begingroup\$ @Fred Rather, 24V is the way to go since that's an industry standard supply voltage level. \$\endgroup\$
    – Lundin
    Aug 19 '21 at 14:29
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Don't. (Or don't yet.)

From your comments on answers, you describe yourself as "new to electronics" and you are unaware even of the ability of different wire gauges to carry current safely.

This is a significant amount of power, with significant risks of things overheating. To make matters worse, you're talking about starting with mains voltages as well, which means you're building yourself an entire mains power supply, and that really isn't a place for novices.

The worst case scenario here is that you burn down your house, and you and your family die in the flames. The next worst case scenario is that you catch a mains shock and kill yourself. The next worst case scenario from that is that you and your family get out but your house burns down, and the insurance company won't pay out for you doing something so blatantly dangerous. All these are not infrequent scenarios when it comes to DIY mains wiring, and that's essentially what you're playing with here.

There isn't a magic secret to working with high-power devices and mains power, the same as driving a car, flying a plane, or any other activity with risks attached. It just needs you to know what you're doing, to know what the risks/issues are, and to take appropriate steps to deal with those risks/issues. At the moment you simply don't know where the bear traps are, and your steps may put your foot in one.

Please don't take this as a reflection on you as a person - it's just that you haven't learnt how to do it yet. With a bit more experience you'll be fine working up to something like this. Right now, I suggest this isn't a good idea.

(Edit to add: I've been working on lower-voltage electronics for about 30 years now, and I've done odd bits of low-key domestic rewiring. I generally know where not to stick my fingers! But if it comes to high-power stuff, or if I need serious domestic wiring done, my first port of call is still getting someone else to do it who's got better skills than me.)

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    \$\begingroup\$ +1 on all counts, except one minor quibble: the worst-case scenario is actually not "everybody dies" but "everybody survives and needs extensive medical care for the rest of their lives while never being able to work". A former colleague of mine was taught that for his rigging certificate: the instructor told them if they ever have a stage collapse at a music festival or something like that, they better hope that everybody under it is dead – much cheaper that way. \$\endgroup\$ Aug 17 '21 at 15:15
  • \$\begingroup\$ Thanks for the concern, but if you read my question again you ll see that i m actually asking for 5v not "main" (i assume by main you mean something like 220v ac? sorry i m not familliar with all the english terms...) I have a CE certified transformer from 220 to 5v, i m not planning on building that myself... Might there be risks with 5v? Sure i could burn a cable with 10 amps, that's why i m asking this question here... A "standard" way that allows me to pass power and data designed for that specific use case would be imho safer than just hacking something... \$\endgroup\$
    – Fred
    Aug 18 '21 at 13:45
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    \$\begingroup\$ @Fred Yes, "mains" is your wall socket supply. Sure you're not building your own transformer, but there are still ways that can go badly wrong which aren't obvious. Bolting a toroidal transformer to a metal case on both sides, for instance. (The bolt melts!) Honestly if you want a 5V DC supply then you'd need a good reason not to just buy a laptop-style "line lump". Way cheaper, easier and safer, as well as less likely to interfere with radios. \$\endgroup\$
    – Graham
    Aug 18 '21 at 20:43
  • \$\begingroup\$ @Graham that's good advice, thanks \$\endgroup\$
    – Fred
    Aug 19 '21 at 6:30
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I am taking a SWAG as there is not enough information to completely answer the question. Knowing the loads would help along with a rough schematic. Have you considered the size of the wire you will need. #16 AWG wire at 2 meters will drop about 0.5V, leaving you 4.5V at the end of the cable with a 10 Amp load. This is about the minimum voltage for many 5V devices Try this calculator, it will help you determine wire size as you do not give enough information to do it accurately. I know this is not what you want to do but consider using a 12V or 24V supply with a buck converter at the end of the 2 meter cable, your voltage will be much more stable especially if it is not a constant load, which you did not mention. You can also use a second buck converter at the controler end, that leaves you with one power supply. Considering you were thinking of PoE by using buck converters you can up the voltage, and reduce wire size even more. OOPS the calculator link did not stick here it is: https://grealpha.com/resources/dc-load-wiring-calculator/calc/voltage-drop/

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    \$\begingroup\$ Thanks this is indeed a very pertinent comment, this is definitely the way to go. \$\endgroup\$
    – Fred
    Aug 16 '21 at 21:40
  • \$\begingroup\$ Thanks for the comment, I am glad it works for you. I also added the calculator, apparently the link disappeared. Have a great Day! \$\endgroup\$
    – Gil
    Aug 17 '21 at 0:09
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Here's an idea to keep things simple and save some money: put the power supply in the device, and power the controller from the device. Doing anything else is likely to require two high power conversion stages instead of one.

I'm assuming you're powering everything from the mains, the device needs 10A at 5V, and the controller needs 5V and minimal current. Now ideally the device would be what plugs into the mains, but if you want the controller to be what plugs into the mains, then there's no reason the mains power can't just pass through the controller and then down the cable to the device. An ordinary mains flex will answer the purpose, but consider that you'll need an earth if the device is not double insulated. Then you need to send 5V back to the controller, and establish a serial link. An inexpensive CAT5 cable could answer both purposes. Use one twisted pair to send 5V power back from the device to the controller. Use another twisted pair for the serial link, or two pairs if you need bidirectional communication.

Now you have two cables, when I'm sure you wanted an elegant solution with just one. You could wrap the two cables together with a braided sleeve. This isn't ideal to send power and data together because of the potential for interference, but you only need a low data rate anyway. For better noise immunity you might use differential signalling for the serial data and maybe put low pass filters on 5V power with enough capacitance at the controller end to ensure stable voltage. If you have a 3D printer you could make a connector housing that combined an IEC connector for the mains power with your choice of low voltage connector into an elegant single unit.

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There are a few companies that make rather expensive "hybrid cable" that has either 2 or 4 100-ohm twisted pairs for ethernet and 4x 16AWG wires for power. Harting and Lapp come to mind.

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I looked up PoE but it's really not enough in terms of power.

IEEE 802.3bt-2018 aka 4PPoE provides up to 71 W (on 100m cabling).

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The truth is that there is no commonly available cable for this.

An easy and reasonable solution is to use a connector that can handle 10A per pin, and get one with enough pins for the power and data, even though the data doesn't need large pins.

If you make your own cable using these connectors, you can make the conductors for the data appropriately sized.

Edit: You should also explain why you can't just use 2 cables bundled together.

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