PCB power socket receptacles

Question

I'm developing kind of relay board and looking for metal contacts for standard (e.g. European) AC power plug which can be mounted to PCB so that AC plug goes throug PCB:

I think it should be something like those ones that used in wall outlets.

Searched for a month, but found nothing. Does anybody knows where to buy such things?

rachaelp · Answer

x_arrange wrote:

But contacts similar to fuse holders on PCB not allowed all the sudden? Why?

I'm not saying for sure 100% that they are not allowed. Gerald seemed to have knowledge that this might be the case, but I am not an expert on the regulations in this area.

But, if you think about the difference between building a mains socket into a PCB and a fuse mounted in a fuse holder on a PCB from a mechanical perspective:

1) A fuse is inserted and it remains in place potentially for a very long time until it blows and is replaced, however a plug may be removed and inserted many times. The mechanical stresses of repeated insertion and removal will be significant compared with just inserting and leaving.

2) The fuse sits in the fuse holder connectors on the PCB, there is no hole required in the PCB through which to insert the fuse. The scheme you outline above required a hole in the PCB for the plug pin to pass through. This is right next to where any PCB mounted fingers would be located, causing a weakness in the PCB at this point allowing more flexing and providing a point which could fail over time.

3) The fuse and fuse holder connectors are fairly low to the PCB and there isn't any leverage to exert forces on the PCB. With the PCB mounted fingers and the plug pins being long in comparison, there is much more leverage for causing forces in the PCB in the right direction for causing failure points as described in item 2 above over time.

I'm not saying I am definitely right and that you can't do this, but I can see potential issues which may make it difficult and explain why you've not found anything suitable in your searching so far.

Anyway, good luck with your project. I hope you find a solution which works for what you need to achieve.

Best Regards,

Rachael

geralds · Answer

Hi, please don't mismatch that different issues. A fuse would not often unplugged, just if you have to change that fuse. But a power cord you can plug in or unplug out every time. So this both of this issues you can't compare directly. Because "there are many on the PCB",,, hm, yes, it works often, but is this right? Main power is on the PCB, yes - AND you have the instruction with it. An example, the power plug for a flat TV: schematic, PCB drawing, an a real photograph The outlet is mechanical stabil (have its housing for the contacts), and is directly mounted on the PCB. The same you can build with the "SCHUKO" (german: Schutzkontakt-Stecker) - Plug; an outlet with the Earth contact. It works! BUT... wow!!! http://media.gettyimages.com/photos/many-wires-on-an-lamp-post-picture-id485451102?s=170667a&w=1007 Best Regards Gerald ---

dougw · Answer

I don't know the standards in Europe, but as far as design practices go, a receptacle needs to have appropriate 3 dimensional mechanical strength. Solder joints are not considered to be adequate for repeated mechanical stress and PCBs are 2 dimensional, so the 3 dimensional mechanical superstructure of a receptacle should be bolted to a PCB, which may need to be extra thick depending on the size and forces involved. I think the reason it is rare to see an AC socket directly on a PCB is it is hard to isolate the mechanical stress on the solder joints. There are PCB mounted power entry connectors in North America, but they generally bolt on to the PCB and the solder pins are generally designed to flex and avoid mechanical stress.

geralds · Answer

exactly. This is what i showed above. Also here in this example: the outlet with an Earth connector. Best Regards Gerald ---

geralds · Answer

High Rachael,

Main-Power Fingers directly tinning on the PCB is absolute unsecure. This is not allowed.

The female gives the main power about 230V with a lot of Ampere.

As showing above in his image - the European standard will disqualifier this.

The power plug must be mounted mechanical strong and electrical secure.

As I see it here, I always want to advise on safety here.

Safety for life and limb is the first thing that counts in the development of electric and electronic devices.

Otherwise, I don't agree with the other proposals. That's just my opinion.

Best Regards

Gerald

---

rachaelp · Answer

Hi Gerald,

I completely agree with you, safety is absolutely paramount hence my above comment was covered in caveats about safety, clearances, ratings, mechanical strength, etc. I personally don't think it's a viable way forward and wouldn't try to do such a thing. I'm not familiar with the various European regulations relating to this, I will take your word for that, but that doesn't surprise me as my gut feeling is that it's not going to work well.

Best Regards,

Rachael

rachaelp · Answer

x_arrange wrote:

Disagree.
Lots of devices uses mains on PCB. Millions of PCB transformers, Power adapters etc..
It's just matter of proper design - correct trace widths, clearances and so on.

Yes of course, mains on the PCB is fine, I've done AC/DC power supplies with 230V AC on the PCB. I think the issue is with this specific idea of mounting the connector fingers directly to the PCB. I don't know the specifics of any regulations around this, geralds may have more info on which specific regulation may prohibit such a thing. I think my concern would largely be making it mechanically robust enough that there wasn't a failure mode which could cause a short.

Best Regards,

Rachael

gecoz · Answer

Hi x_arrange , I believe the product you are developing falls within the remit of the Low Voltage Directive (LVD) 2014/35/EU, if you are planning to sell it in the European Union market. In particular, in your case, for the connector to be allowed, its safety protection needs to be guaranteed (assuming the rest of your board is already compliant). Usually, to satisfy the safety requirements, is enough to follow the EU/IEC standard that adresses the subject. For the connectors, if I'm not wrong, I think the standard to refer to is IEC 60320 . This standard covers the typical connectors used on appliances/boards. If your connector is a custom design, then you need to certify its safety, which could be a long and expensive process. Fabio.

rachaelp · Answer

This isn't something I have really thought about doing before, it's probably hard to find this sort of thing because there are all sorts of safety implications and clearances required when dealing with mains voltages.

I did do a quick search and the closest thing I can find to what you are looking for is something like this: http://uk.farnell.com/te-connectivity-amp/1744128-3/pcb-contact-pin-solder/dp/2102402?ost=1744128-3&scope=partnumberlookahead&exaMfpn=true&searchref=searchlookahead&iscrfnonsku=false&ddkey=http%3Aen-GB%2FElement14_United_Kingdom%2Fw%2Fsearch

However, there aren't any details on it's electrical specs so it may not be suitably rated for this application and I am not sure whether you'd be able to make it mechanically work given you want to plug through the PCB so you'll be putting a cut out in the board where the mounting pad will likely need to be, and even if you can get that to work, will there be enough rigidity or will the connector fingers flex the PCB too much as the plug is inserted?

Best Regards,

Rachael

geralds · Answer

In Europe, so as you shown, it is not really allowed. But you have some power plugs for "cold devices", white goods, that you can use for PCB mounting. http://www.farnell.com/datasheets/2081897.pdf?_ga=2.84381916.437430279.1512899497-63280803.1512144825 250VAC 10A Stecker Netzsteckverbinder | Farnell AT You can select between with or without build in fuse, also filters. You will need a complete plug with mechanical mounting components. You also have to meet European industrial standards. So be careful! - the Inlet is the male that gets the power voltage. - the Outlet is the female that gives the power voltage. Best Regards Gerald

x_arrange · Answer

Disagree. Lots of devices uses mains on PCB. Millions of PCB transformers, Power adapters etc.. It's just matter of proper design - correct trace widths, clearances and so on.

PCB power socket receptacles

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