How to house/connect relays properly (according to DIN/ISO)

Hi!

I am doing a project were I am using a 8 relay module. My next step is to connect it to several 220 V lines but I want a good piece of advice before I go this road.

I have read about plastic or wood boxes to keep the relays separated. I have also thought of cutting cable extenders (1 cable from each line) to put them in the relay, but I would like to know if I should put a fuse in each and how they should be separated according to a norm.

I am aware of the possibility of using wall plugs that connect with transistors through a signal as an alternative, but I want to do this project in a compact form and also avoid delays with the relay control.

I checked on the internet but none gave an answer that refer to an official norm (maximum safety/in case something goes wrong). Can someone point me towards the right direction?

Thanks in advance!

220V?

Do you have experience with working with this?

If not, I suggest a licensed electrician.

UL60950
6.4mm or greater of separation between lines is safe.

JMeller:
UL60950
6.4mm or greater of separation between lines is safe.

Several years ago one of my customers wanted to pass UL/CSA on his product. The 1600 volt testing caused arcing between pads on a series of resistors and caused several different board redesigns.

One of my current customers is doing the same test with the 1600 volt test and as of Friday had destroyed 5 units.

So, you should also be aware of the standard tests, even though you are not certifying anything for sale. I don't think any of the little Chinese relays will pass the test. Certainly not the circuit boards they are mounted on.

Be careful!

Paul

Hi,

Oh, this is the american one. It should greatly help, thanks! I will check it properly.

Surely, I will get an electrician or direct advice from him to do this, thanks for the heads up.

So, out of curiosity... If you are certifying a product for 220 V, do you have to go to test them to 1600 V?! Thanks, I will.

Actually only one of the lines is 220, the other ones are 12 V. I will carefully start with the 12 V ones when I acquire more knowledge.

If I have a 12 V adaptor (I mean, 220 V wall plug that converts to 12 V as an output), how can I calculate if this adaptor will suffice for 3 elements I want to connect?

Should I just add the amps each of them need and then check if the adaptor supplies that many and then check on a way to put all the elements in parallel?

At the beginning I thought of adding so many adaptors as elements, but maybe I could save 1 or 2. Any ideas?

I studied electricity at the university but it has been quite a while since then. I have to check that too!

russelcrowe_:
So, out of curiosity... If you are certifying a product for 220 V, do you have to go to test them to 1600 V?! Thanks, I will.

No; however, if you want to be on the safe side and adjust your design for 1600vac, simply increase the minimum distance to 7.2mm of separation. As Paul alluded to earlier, the spacing applies to all connections, traces, and relay contacts.

Only from curiosity: what part of the world are you living in?

Mains voltage has been changed during the 1990ies (and earlier) from 220 or 240 to 230 Volts in many parts of the world. :slight_smile:
Of course there are some countries left that use 220 Volts like China, Greenland, Argentina and several countries of Africa. But whole Europe, Australia, Russia, India and many others use 230 Volts now. :slight_smile:
And of course North Amercia is using 120 Volts still.

World Map of Mains Voltages and Frequencies

Edit: Most part of Australia is still 240 V (thank you Paul__B). So the map (link did not work - sorry - but now fixed) may not be right with this area.

Thanks for all your replies and explanation about tests!

I am living in Europe. Thanks for the explanation! I know know that the main is 230 V :slight_smile:

This thread has missed several of your questions. Yes, you should be fusing any mains connections into a device you are controlling. Sizing will depend upon the loads and the relays selected for which you have provided no information.

This comment:

I have also thought of cutting cable extenders (1 cable from each line) to put them in the relay, but I would like to know if I should put a fuse in each and how they should be separated according to a norm.

Makes no sense whatsoever to me. Could you please explain what you mean by cutting a cable from each one?

As a general comment, the majority of the Chinese 1/2/4/8/16 channel relay boards sold as Arduino compatible devices would not pass a CE hazard assessment if used in a commercial product due to the clearance and creepage distances in the pc board layouts. The actual physical relays are okay (in most cases) but the board designs are usually lacking the required spacing. Most boards also lack the extra cost step of creating an air gap between the high voltage contact side of the relays.

The are other factors that must be considered as well, the most important being proper earthing when connecting to mains voltages. As mentioned, it would best to consult a qualified electrician in your country if you are unfamiliar with the necessary methods to realize a safe and reliable installation.

Mains voltages have not been changed to 230V, the standard was changed to 230V +6% -10% which covers 220 to 240, but only the standard has changed, not the hardware.
UK power is 240V, European 220V, common standard for both applied after the fact.

Attempting to change the actual distribution system would be expensive and pointless.

It may be different in other regions, but where I live (Vienna), mains voltage has changed. During the 80ies it was 220 V (nominal), now it is 230 V (nominal). It is a "real" change, not the standards only. You could/can measure it with an AC volt meter.
After the change (close to the millennium), there were problems with "sensitive devices". I do remember problems we had with some elder tape recorders (I was working at a radio station).

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Cheaper is irrelevant. Those 5mm/5.08mm screw terminals won't pass 220VAC testing. 5 < 6.2 or 7.2mm clearance requirement.

OP mentions only 1 relay is for 220V. Personally I would use one of the 2/4/8 relay boards to drive an off-board (pre-)certified contactor.

Advatanges:
Pre-certified
Easily replaceable
220VAC is never on the circuit board.

Disadvantage:
Off-board - but if the unit is designed properly that effect can be minimized.

So you're saying those relays are sold as is, no certification ?
In his first line - 8 relay module

Sold as is. Buyer beware.

The only two things I would begin to think are correct are the specs of the parts used and the of the PCB material (hopefully FR4 and 94V-0). I doubt they spent the money to send of the board to ensure the layout was correct and safe for 220/240VAC.

Hi,

thank you everyone for your answers.

This thread has missed several of your questions. Yes, you should be fusing any mains connections into a device you are controlling. Sizing will depend upon the loads and the relays selected for which you have provided no information.

Indeed, I still lack the DIN norms but I was offered the american ones. I apologize, it is my first/second post.

The 220 V load will be an air pump (5W, 50Hz) which I hope it will do the job.
The other lines will be 12 Volts and they will probably be 4 lines, although I am thinking of adding a fifth one.

Product information:

The 8 module relay I have has already been mentioned in this post:

Brand: Songle
Name: SRD-05VDC-SL-C
On on the side where the screws are (for the 220 V line and the 12 V lines) it states 10 A and 250VAC/30DVC

I assumed that the load could not damage the relay as it would need 5/220 * 1000 = 23 mA.
It could also be that the pump is too small and I have to go for a bigger one, but still low amperage.

Makes no sense whatsoever to me. Could you please explain what you mean by cutting a cable from each one?

Sure thing. I mean using a cable extender (220 V) that has two cables. Opening the isolation, cutting the mass one and put both ends in the relay. Afterwards, seal the relay in a box (plastic/wood?) according to DIN/experienced electrician. This would give me a plug to plug in the wall and an inlet where I can connect the 220 V device to (pump in this case). The other lines I will power through a 12V adaptor with jack connections (I think there is no need to further explain the 12V side).

The actual physical relays are okay (in most cases) but the board designs are usually lacking the required spacing. Most boards also lack the extra cost step of creating an air gap between the high voltage contact side of the relays.

Those 5mm/5.08mm screw terminals won't pass 220VAC testing. 5 < 6.2 or 7.2mm clearance requirement.

If I am connecting the 12 V until relay 5 and I connect the 220 V in relay 8, there would be a spacing of 3.4 cm between the last 220 V and the first 12 V line. Unfortunately this does not solve the clearance requirement, but at least, no 220 V can get to touch an additional 220 V line.

Would I avoid all this issues if I found a pump that works with 12 V instead of 220 V?!

So you're saying those relays are sold as is, no certification ?
In his first line - 8 relay module

The only two things I would begin to think are correct are the specs of the parts used and the of the PCB material (hopefully FR4 and 94V-0). I doubt they spent the money to send of the board to ensure the layout was correct and safe for 220/240VAC.

Do you mean then that ven if I leave this gap, the product is unreliable? Which one would you suggest then?

So, to summarize, what I got is:

-My main is 220V (EU).

-The 8 module relay I have (Songle) does not meet the clearance requirement. (5mm/5.08mm screw terminals < 6.2 or 7.2mm, won't pass 220VAC testing). Which model would (EU/DIN norm/electrician needed)?

-Would I avoid all clearance this issues if I found a pump that works with 12 V instead of 220 V?!

-The module relay might not be safe for 220/240 V, although stated in the module.

-I need to fuse the 220 V line (are the 12 V ok without?). Requirements for the fuses (EU/DIN/electrician norm needed)?

Is anyone familiar with the norm EN 61810-1? Could this one be the one I have been looking for?

online calculator

Chances are you would need to fabricate your own board to find and/or ensure the clearance.

As I mentioned, I would use a contactor driven by a relay board. The contactor has the 220V certifications and the relay board meets the requirements to handle 12v.