Basic AC/DC Din Rail Question

[ScottyB]

Hi All,

Long term lurker, first time poster.  Go easy on me!

I am trying to understand the basics of a AC/DC power supply - specifically what is the safe way to wire it.

I have a number of devices that require 1A at 12Vdc - 5 in total.  I am looking to do away with their "UK plugs to bare wires" and replace with a din rail power supply.  I can workout the maths to make sure I give them enough current, but my question is more basic and relates to wiring.

Can I simply, take a 13 amp plug, strip the wires and use them for the input, and then on the output terminal put as many wires to the devices as I can physically fit without fear of them falling out without causing a problem or safety issue?

Secondary, if I order cable for the DC out to the devices what is best practice in terms of gauge of the cable - I appreciate I would need sleeve them for identification.

I am looking at something like this if that helps paint a picture

https://cpc.farnell.com/tiger-power-supplies/din240-12/ac-dc-din-rail-power-supply-12v-dc-16a-192w/dp/PW05753?mckv=s_dc|pcrid|224680288544|kword||match||plid||slid||product|PW05753|pgrid|48556615353|ptaid|pla-835922884783|&CMP=KNC-GUK-CPC-SHOPPING-945655906-48556615353-PW05753&s_kwcid=AL!5616!3!224680288544!!!network}!835922884783!&gad_source=1&gclid=EAIaIQobChMIltflmffQhgMVl5tQBh0c4A3TEAQYASABEgLdjPD_BwE

[Kjelt]

So DIN components are designed to be used on a DIN rail mounted in a closed case.
This means not all components have:

- fully insulated and touch safe connectors
- even an input fuse that will blow (but many PSUs do have these)

I am not sure what you want to do but a closed integrated power supply might be better for your purpose, even then you have to make sure that there is some form of mechanical cable stress relief and if not manufacturer supplied a protection of the input mains connectors for direct touch.
You really don't want a visiting child to touch your project and get shocked.

[ScottyB]

Thanks for the reply.  The DIN rail power supply will be in a small enclosure, so not danger of being "touched" by accident.

Does the wiring I described make sense though?  Is that how it should be done?

[Kjelt]

Does the wiring I described make sense though?  Is that how it should be done?

Officially no, you put max 1 wire per connector with a gauge that meets the current requirements of all the devices connected.
That one wire goes to a so called din mounted terminal block(s) where the terminals can be connected together (bridged) with special bridgeconnector to create more output connections of the same source for your wires. There are also ready made terminal blocks with multiple connections bridged.

A cheaper and also safe way of working would be using the Wago 221 series connector if 1 input and 4 output would suffice.

[Xena E]

... if I order cable for the DC out to the devices what is best practice in terms of gauge of the cable - I appreciate I would need sleeve them for identification.

How long are your cable runs going to be?

[ScottyB]

Thanks Kjelt, appreciate your help.

Just to be clear, you take the output from AC/DC power supply and connect to the the terminal blocks how?  Do they have a common "input" that then break/distributes the power out to the blocks to give you the required number outputs? (positive and negative DC per block?)

Similar question on the WAGO - how would you join 5/6 pairs (Positive/Negative to the DC) to the input on a WAGO? I use WAGO to join cables before, but not as a distribution of one input to many outputs - is it simply a case of taking the Positive output from the AC/DC PSU to one WAGO, and the negative output from the AC/DC PSU to another WAGO?

I think I prefer the connection blocks - looks neater, but not sure how they are connected up.

[ScottyB]

1-2m max cable lengths.  I have a number of modems I want to tidy up, so nothing heavy duty.

[Kjelt]

Just to be clear, you take the output from AC/DC power supply and connect to the the terminal blocks how? 

So there are many terminal blocks also different manufacturers.
Also with screw terminals like the example below and with clamp terminals.
If you use screw terminals with stranded wire you need to crimp a ferrule on the wire, if you use clamp terminals that is not needed.

I show you an example I have lying around.
The left terminal block has 4 connectors but only 2x two are connected.
The upper two are connected and the lower two are connected.
So you could use the lower row for instance for the DC- and the upper row for the DC+

Then you connect more blocks together with the yellow bridges (see pictures) and they get connected.
Make sure you know in front how many blocks you want to connect since that is the size of the bridge, if you need one more you need a different larger size bridge (at least with these terminal blocks)
When bridging, all the bridged upper rows get connected and the all the bridged lower rows get connected.

If this confuses you take the other sort of terminal block: the right terminal block also has 4 connectors but they are all connected.
So here you can bridge them also together but each terminal block will add 4 connectors (upper and lower rows are internally connected as you can see)

Some bridges need to be screwed in like the example below, there is one place where you can fit them, others can be put in with only vertical force like a connector.
You also have terminal blocks with only two connectors, the same principle but then for instance for 1 input and 5 outputs, you need to bridge three terminals per polarity (3 for DC- and 3 for DC+)

Similar question on the WAGO - how would you join 5/6 pairs (Positive/Negative to the DC) to the input on a WAGO?

So lets say you have one output of the PSU and four to the devices.
You take one black wire (DC-) from the PSU to one of the Wago clamp inputs, the other four you connect wires that will have DC- to your device.
Same for DC+ then red wire (DC+) from the PSU to one of the Wago clamp inputs, the other four you connect wires that will have DC+ to your device.

I use WAGO to join cables before, but not as a distribution of one input to many outputs - is it simply a case of taking the Positive output from the AC/DC PSU to one WAGO, and the negative output from the AC/DC PSU to another WAGO?

Yes it is.

I think I prefer the connection blocks - looks neater, but not sure how they are connected up.

They can be quite expensive, also if you add bridges and a plastick end piece (to insulate the last connector).
Make sure if you order them, the bridges are correct for the terminal blocks (don't ask me how I know  ) and also the plastick terminator.

Hope this helps a bit and does not confuse you more 

[themadhippy]

A cheaper and also safe way of working would be using the Wago 221

As your going to be using  din rail you could use the wago din rail holder with the 221's


https://www.sparksdirect.co.uk/wago-221-500-din-rail-mounted-orange-connector-carrier-for-use-with-wago-4mm2-221-series-lever-connectors-pack-of-10

[ScottyB]

OK so I have done a bit of digging, it seems I would "jumper" a number of connector blocks together - is that correct?

So take the output form the AC/DC PSU, connect positive one side of the block (say top) and the negative to the other side (say bottom).  Then jumper blocks after this to match the number of pieces of equipment I need to the number of blocks. 

However, which type of connector would I need, Multi level?  Single level?

My concern is that seem to have one connector - which means shorting the Pos & Neg which obviously cannot be right.

Sorry - I am trying to understand.

[ScottyB]

A cheaper and also safe way of working would be using the Wago 221

As your going to be using  din rail you could use the wago din rail holder with the 221's


https://www.sparksdirect.co.uk/wago-221-500-din-rail-mounted-orange-connector-carrier-for-use-with-wago-4mm2-221-series-lever-connectors-pack-of-10

That seems simpler - just positive one and negative to the other.  Seems logical and will go with this.

I did post before seeing your reply, but I am curious to know how I would do with bridge connectors.

[ScottyB]

This is crystal clear now - much appreciated.  I am off to have a play.

[Kjelt]

Sorry to have confused you, indeed with single level (2 connectors per terminal block) it is easier to grasp and prevent mistakes.
But the WAGO way is indeed the easiest way (and cheapest). 

[ScottyB]

Perfect - thanks team.

[ScottyB]

I have seen Wago have jumpers for the 221 series, so in theory, I can get two 5 ways and get 9 outputs by using the jumpers to connect them together.  I'd replicate this for negative and positive.

That seems to be ideal to me.

Any reason why I cannot do that?

[Kjelt]

You mean like this picture ?
Then if you have 2 5 ways you loose two for the jumper and are left with one input and 7 outputs.
How many do you need ?

[Kjelt]

If you need that many outputs it might be interesting to have a look at power distribuition block, for instance PTFIX from Phoenix Contact.

https://www.phoenixcontact.com/en-pc/products/distribution-blocks

Make sure the clamps can clamp the wire gauge you were planning to use.

[ScottyB]

Yes exactly like tyst image. 6-7 outputs is all I need, but those phoenix connectors look good.

I assume you use one for positive and the other for negative?

[Kjelt]

Yes indeed and choose the color matching the polarity.

For instance
PTFIX 12X1,5 RD
PTFIX 12X1,5 BK

[ScottyB]

Yes indeed and choose the color matching the polarity.

For instance
PTFIX 12X1,5 RD
PTFIX 12X1,5 BK

Awesome advice. Thank you so much.

[tooki]

The PTFIX line is great. I'm assembling something for someone right now using a pair of them to do exactly the same thing: take a beefy DC supply and distribute power to a bunch of loads.



But broadly speaking abour DIN rail terminals: yes, you use jumpers to bridge individual terminal blocks. FWIW, while I really like Phoenix Contact's terminal blocks (they do really well with low-profile ones, and have lovely miniature ones, the PT 1,5 series), the pricing on their jumpers is ludicrous. WAGO has higher pricing on the terminal blocks, but their jumpers are far cheaper and they have a much wider array of jumper sizes and types, including clever ones that squeeze by each other in the same jumper row! Important: jumpers are NOT interchangeable between brands, or even between series, and they must match the pitch of the terminals you're using (e.g. the little ones are 3.5mm pitch, the most common ones are 5.2mm, and bigger and bigger ones exist too).

As someone who only really started using DIN rail terminals in the past year: I suggest doing some "practice projects" with them to get the hang of it.
1. order a dozen or so of basic single-level, no-special-tool, 4-terminal terminals (like Wago 2202-1401 or Phoenix PT 2,5-QUATTRO)
2. order a few matching jumpers (e.g. 8x 2p, 4x 3p, 4x 4p: Wago 2002-402 / 2002-403 / 2002-404 or Phoenix FBS 2-5 / FBS 3-5 / FBS 4-5)
3. order a few end covers for those terminals (Wago 2002-1491 or -1492, or Phoenix D-ST 2,5-QUATTRO)
4. order a few 30cm DIN rails
5. order a few pairs of DIN rail end blocks (like Wago 249-116 or Phoenix Clipfix 35-5)
6. use these to wire up some projects. You will quickly figure out how to "think" with these terminal blocks.
7. study the catalogs of a few manufacturers of DIN rail terminal blocks.
Phoenix Contact's catalog is better than Wago's at providing schematics that make it clear how each terminal block is wired; Wago is much better at presenting what accessories are compatible with a particulat terminal block. Weidmüller is somewhere in between, having the best schematics, and good lists of compatible accessories (but without images of the accessories like Wago). Studying the catalogs while you learn to wire things up with them will give you ideas on how to do things smarter.


Now that I think about it, due to the overall most useful catalog, you might want to go with Weidmüller to begin with. (I just don't have any part numbers handy for them.)

I know that both Wago and Phoenix Contact also have starter kits for this stuff, so maybe Weidmüller has some, too.

[tooki]

P.S. Here's a small rack-mount control cabinet I finished recently, using Phoenix Contact terminal blocks. The left side of the rail has the 230V connections on PT 2,5-QUATTRO blocks, as well as the 24V DC power supply; on the right are the safety relay, relays, and then the low-voltage connections using PT 1,5-QUATTRO terminal blocks. The device this controls also has a tiny DIN rail in it with a few PT 1,5-QUATTRO on it. (In many positions, I don't need all 4 terminals of a PT...-QUATTRO terminal block, but it's cheaper and easier for me to just buy the 4-terminal QUATTRO versions in bulk than to buy small amounts of the 2- and 3-terminal versions, and the end covers for them, etc.)

[ScottyB]

Thank you - all good advice.

I’m opting for the Wagos in a din rail carrier. Seems neat and simple.

I have had second thoughts about the power source, not liking the idea of live AC having a remote chance of being an issue, so going with a AC to DC brick, cut the connector off, then it’s DC everywhere.  I will tin the leads.

I do have it in an enclosure but @Kjelt got me thinking if someone was to poke around when I’m not here……not worth thinking about.

Such a helpful community and I’m definitely going to stick around.

[ScottyB]

P.S. Here's a small rack-mount control cabinet I finished recently, using Phoenix Contact terminal blocks. The left side of the rail has the 230V connections on PT 2,5-QUATTRO blocks, as well as the 24V DC power supply; on the right are the safety relay, relays, and then the low-voltage connections using PT 1,5-QUATTRO terminal blocks. The device this controls also has a tiny DIN rail in it with a few PT 1,5-QUATTRO on it. (In many positions, I don't need all 4 terminals of a PT...-QUATTRO terminal block, but it's cheaper and easier for me to just buy the 4-terminal QUATTRO versions in bulk than to buy small amounts of the 2- and 3-terminal versions, and the end covers for them, etc.)

Looks good. I’m not quite in that deep, but my understanding is infinitely better as of today. Thanks.

[Kjelt]

P.S. Here's a small rack-mount control cabinet I finished recently,

Hi Tooki
Not to criticize just to advance the professionality of your work.
Add cable ducts, they are not that expensive, place them horizontally above and under each Din rail and vertically on the sides.
Try to avoid combining mains and low voltage next to eachother butbyou know the EMC guidelines.
Cover it up and it looks way better. You do have the room for it.