24VAC via Cat6

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Paul1977

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#275821 11-Sep-2020 11:19

I've given up on the official Ring Plug-In Adapter coming back into stock any time soon, so will be purchasing this one from JayCar tomorrow instead.

I'll be using an existing Cat6 cable run to get the power from the the power supply in my network cabinet to the doorbell. What is the best way to do this?

Since the Cat6 will be used only for power, should I use all 4 pairs?

I read an old post on a another forum (which I can't find now) suggesting joining the ends of all 4 coloured wires together as one, and all 4 striped wires together as one (something about this making the resistance equal on each side because of the different twist rate of each pair). Is this the best way to do it?

I've also read other posts saying to just use a single pair, but would more copper be better?

Thanks

EDIT: or I could potentially get some bell wire and run it from a power point in the attic to keep the AC away from the other network cables (at only 24VAC would this even be an issues re interference any way?)? No guarantee I could pull new cable through, but I might be able to. Would this be a better idea if I can get the new cable to the bell?

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#2562213 11-Sep-2020 11:51

You should actually use both wires in a twisted pair - in effect following the passive poe standard which uses pair 4+5 and 7+8 for positive and negative. Since you are just using AC it doesn't matter which way around you do this.

I don't know what connectors you are using but if it's a standard 2.1mm you can buy a pair of massive POE adapters with a 2.5mm plug and ethernet at one end and and 2.5mm socket and ethernet at the other end quite cheaply.

cyril7

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#2562214 11-Sep-2020 11:51

Hi, yes regularly done, I would just collect together say the blue/bluewhite and green/greenwhite as one wire and orange/orangewhite with tan/tanwhite as the other wire, twist them together and put in a screw terminal block or whatever, job done.

Cyril

1101

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#2562219 11-Sep-2020 11:58

That jaycar power pack is AC , not DC

make sure your device accepts AC input , or the magic smoke will come out . Most devices want DC .

Then you need to know how much current your device draws .
You could just try and see, just check the voltage drop : measure the voltage at the device when its on.
Connect all wires into 2 . Label the cable at both ends so the next person knows its not for data .

Paul1977

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#2562230 11-Sep-2020 12:17

1101:

That jaycar power pack is AC , not DC

make sure your device accepts AC input , or the magic smoke will come out . Most devices want DC .

Then you need to know how much current your device draws .
You could just try and see, just check the voltage drop : measure the voltage at the device when its on.
Connect all wires into 2 . Label the cable at both ends so the next person knows its not for data .

Definitely AC required, thanks.

Paul1977

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#2562231 11-Sep-2020 12:21

Is the relatively low AC voltage of 24VAC likely to cause any issues being run close to other network cabling. Mains AC voltage can cause network interference, but what about low voltage AC?

K8Toledo

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#2562248 11-Sep-2020 12:25

Paul1977:

Is the relatively low AC voltage of 24VAC likely to cause any issues being run close to other network cabling. Mains AC voltage can cause network interference, but what about low voltage AC?

Needs to be seperated. OTTOMH by 50mm.

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cyril7

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#2562251 11-Sep-2020 12:34

Ahhh, not true, 24V AC is ELV, this can co exist with TLV, so no separation is required.

Edit: the above is safety reg, as for interference, network signals are pretty immune to 50Hz, the magnetics in the coupling transformers of a NIC simply dont respond to anything much below 100kHz so any LF (ie 50Hz) is naturally filtered as the coupling transformer acts as a HP filter. What is of concern (but not with your application) is HF rubbish on power cables that comes from switch mode power supplies and the like, this is more of a problem than the 50Hz itself.

Cyril

richms

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#2562253 11-Sep-2020 12:35

You want to fuse it or get some PTC protection at the power supply end incase someone busts the doorbell off and trys shorting it out thinking it will bypass things. That wall wart _may_ be short circuit protected, and it may have a current limit less than what it takes to make the cat6 go all smokey, but it might not. So best to be safe.

Richard rich.ms

K8Toledo

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#2562255 11-Sep-2020 12:37

cyril7:

Ahhh, not true, 24V AC is ELV, this can co exist with TLV, so no separation is required.

Cyril

Yeah agreed, I just checked TFC guidelines it only applys to mains power.

Paul1977

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#2562266 11-Sep-2020 13:04

cyril7:

Ahhh, not true, 24V AC is ELV, this can co exist with TLV, so no separation is required.

Edit: the above is safety reg, as for interference, network signals are pretty immune to 50Hz, the magnetics in the coupling transformers of a NIC simply dont respond to anything much below 100kHz so any LF (ie 50Hz) is naturally filtered as the coupling transformer acts as a HP filter. What is of concern (but not with your application) is HF rubbish on power cables that comes from switch mode power supplies and the like, this is more of a problem than the 50Hz itself.

Cyril

Thanks, that's good to know (I don't understand it, but good to know it won't cause an issue!).

Paul1977

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#2562274 11-Sep-2020 13:23

richms:

You want to fuse it or get some PTC protection at the power supply end incase someone busts the doorbell off and trys shorting it out thinking it will bypass things. That wall wart _may_ be short circuit protected, and it may have a current limit less than what it takes to make the cat6 go all smokey, but it might not. So best to be safe.

I have a "Pro Power Kit v2" which gets spliced into the circuit. I think it's meant to regulate power, so might offer that protection as well?

Click to enlarge:

EDIT: Just had a quick online chat with Ring support, and they said that the Pro Power Kit v2:

has a PTC fuse on the circuit board to help protect the Ring Pro if there's a momentary short circuit

I assume that probably means if someone did what @richms describes that it would blow the fuse in the Pro Power Kit (presumably killing it) but would prevent the circuit and cable from over heating?

EDIT 2: It's a resettable fuse, so even better.

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webwat

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#2573119 23-Sep-2020 22:52

Paul1977:

Is the relatively low AC voltage of 24VAC likely to cause any issues being run close to other network cabling. Mains AC voltage can cause network interference, but what about low voltage AC?

Interferance from AC is more about the current as far as I know, but that could be mitigated if you stick with white for one phase and colour for the other, the twist is designed to cancel low frequency interferance. I can't imagine a door bell drawing much power, but if its got a built in camera then yeah join the 4 wires.

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neb

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#2573468 24-Sep-2020 12:58

cyril7:
Hi, yes regularly done, I would just collect together say the blue/bluewhite and green/greenwhite as one wire and orange/orangewhite with tan/tanwhite as the other wire, twist them together and put in a screw terminal block or whatever, job done.

And put red tape or something similar around the cable ends to mark them as non-Ethernet and definitely use a screw terminal block and not RJ45s as connectors anywhere no matter how convenient it may be. Cat6 with non-Cat6 signals on it is risking problems in the future.

richms

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#2573660 24-Sep-2020 17:12

Also common the 2 wires in a pair for + and another pair for -

If you split the pairs and put DC on it, then that will be across any magnetics that the cable is plugged into and ruin them, whereas there is no DC path between pairs so plugging one in when wired on entire pairs will not cause any current flow thru the device that you mis-connect.

Richard rich.ms

Paul1977

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#2574039 25-Sep-2020 09:35

webwat:

Interferance from AC is more about the current as far as I know, but that could be mitigated if you stick with white for one phase and colour for the other, the twist is designed to cancel low frequency interferance. I can't imagine a door bell drawing much power, but if its got a built in camera then yeah join the 4 wires.

@webwat I ended up using the brown pair for phase and blue pair for neutral, as most people seemed to suggest that would work fine.

It's working fine as far as I can tell, but I am curious about the idea of using all the whites for one and all the colours for the other if that is optimal for mitigating any potential interference. I'd only seen this suggested on one other forum and was one of the reasons I asked here. The Cat6 going to the door bell is bundle with all the data carrying cables for about 10m before it splits off.

If connecting all the colours for phase and all the white for neutral (or vice versa) is optimal to mitigate interference then that sounds good to me, but is there any downside to doing it this way? I guess I'm wondering if there is a catch to this, as most people don't seem to suggest it.

I don't really understand how it works. Some have suggested interference wouldn't be an issue at no matter how I do it, while I read on other forums that it could be.

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