Grounding Necessity and Heat Sink Compatibility for Chinese LED Power Supply (50W, 20-39V DC, 1.5A)

Question

Hello. I have a Chinese LED power supply (50W, 20-39V DC, 1.5A). The power supply has a grounding cable, but is it necessary? Will the heat sink that will cool the LEDs be a good place for grounding (if I have to connect it of course)? Thank you in advance for your answer. Regards.

ryszard1955 · Accepted Answer

Odd that the power supply needs to be grounded, but the best point is the ground at the output of the power supply.

tomiok · Accepted Answer

Here you can see how most of these power supplies are made: The first picture looks nice: Second - everything seems to be nicely explained: The third one below (please note the upper left corner of the photo): You can see what Chinese manufacturers are doing with the protective conductor.

tomiok · Accepted Answer

Since you're building it yourself, you should take care to comply with electrical codes, and provide protection against electric shock. Added after 2 [minutes]: You should connect the protective conductor if the housing is metal (i.e. conductive), it does not matter if it is aluminum.

kolo333 · Answer

The power supply looks like this: I don't know whether to connect this ground to, for example, a heat sink or not. What do you think? Regards.

scalok · Answer

You have clearly drawn to connect. Y/G is yellow-green. That is the protective conductor.

jdubowski · Answer

You connect the green-yellow wire to the mains protective conductor.

ryszard1955 · Answer

I replied to this thread before I saw the photo of this power supply, but it is clearly visible that the power supply is connected to the mains with a typical cable with a protective conductor (yellow-green), from the power supply side, the protective conductor is usually connected to the metal elements of the housing.

Anonymous · Answer

The end of the cable seems to have a ring end. Is the power supply not fastened somewhere by screwing?

ryszard1955 · Answer

If there are holes for screwing on the bottom of the metal housing, then this eyelet is probably just inserted into the screw that fixes this power supply.

kolo333 · Answer

Thanks for the answer. The power supply has an aluminum housing, but there is no place to screw the eye. And again the question: the LEDs will be glued with thermally conductive glue to the heat sink. Can this eyelet be screwed to this heat sink where the LEDs will be glued? In my opinion, there will be no puncture, because the pins (+ and -) are only on one side. The other side (the one where the glue will be) will insulate against any voltage. I understand correctly?

ryszard1955 · Answer

If the heatsink is strongly electrically insulated then yes, but I wouldn't advise it, it's better to attach the protective conductor to the housing.

tomiok · Answer

The protective wire is added to connect to the housing of the LED lamp that it powers, do not mess with the power supply itself.

jdubowski · Answer

Of course, the housing must be connected to the mains protective conductor.

kolo333 · Answer

The point is that I cannot connect the ground to the CREE diode, because ... there is no such possibility. So I understand to try to connect this ground to the power supply housing. If there is no place to screw the eyelet, maybe you have some other way to connect this cable to the power supply housing (glue, tape, etc.)? Thanks in advance for your answer. I'm watching Chinese LED power supplies now. Each power supply has a grounding cable, but not all have a description on the casing. There are just two cables L and N and that's it. I think that without grounding the driver will work without a problem, but the diode is too expensive to check it. :D Change of mind. I think the cable should be attached to the case of the power supply. I have analyzed several power supplies and many are designed this way.

kolo333 · Answer

Could you elaborate? I don't see any ground wire there. Some power supplies have no grounding at all. L and N and nothing else. I know that some people connect the ground with the N cable. One user did it, but best of all - he insulated the eyelet with insulating tape. I don't understand it completely. I guess I'll have to invest in a normal Mean Well power supply, which... also has no ground. I'm just afraid to connect diodes that cost a little to a Chinese power supply. Yesterday I connected and screwed the ground to the aluminum housing of the LCD TV. Everything worked without any problems. Well, but with a ready connection, I will not have room for such a connection. Either the power supply housing or the diode cooling radiator or ... without grounding. Gentlemen, will you help? Thank you.

ryszard1955 · Answer

Most power supplies of this type do not use a protective conductor at all. If everything is well insulated inside, you can do this. After all, these are low wattage devices and there is no style with moisture or water, so it is not necessary to ground everything. Do mobile chargers have protective conductors connected? I don't think so.

tomiok · Answer

You can see the cut end of the protective wire, even though it is led outside, and there is even a description of what to connect it to. I added an arrow.

jdubowski · Answer

After all, this cable comes out of the power supply - it is already connected inside. Where are you inferring from? And anyway, probably this protective wire is inside the power supply connected to one of the output wires (probably negative). Do you mean some kind of external case where you will put the power supply? is it metal? If so, drill a hole and put on a clamping screw, connect PE from the mains cable and PE from the power supply to it. What do you not understand? Need for protective grounding? The one in the picture is grounded. Acquisition of non-Chinesegio will be bordering on impossible. And grounding is not there to protect the diodes and the user. For what reason? Check with an ohmmeter between the output wires and PE - there is no connection? No, because you'll kill someone. These are class II devices. Such a device is not the power supply of the author of the thread.

ryszard1955 · Answer

But since there is already a network cable with a protective conductor and the housing is metal, so this wire should be connected to the housing. And if there is a place marked on the board to connect the protective conductor, then it should be connected there. Perhaps the heatsink is also electrically connected.

kolo333 · Answer

It doesn't come out of the power supply, it just goes into the power supply. It is not connected inside the power supply. Please see the first photo of my power supply. He is not at all connected. Please also see the CXA3070 diode, which will be connected to the power supply. She has a size of 30x30 (mm). I meant the power supply. It's aluminum. I'm not talking about extra housing. Yes, in this case I don't understand it. There are a whole lot of ungrounded power supplies. Yes, this one does, but only cable. Mean Well is another power supply that is often used for this diode. He's much more expensive. Heat sink + fan + diode glued to the heat sink. Also on the heatsink is the power supply (isolated). I have nowhere to ground. I don't understand. Maybe in a different way - solder the grounding to the PSU housing? I repeat again - POWER SUPPLY. Will be OK?

tomiok · Answer

Since there is no original mount, solder as much as possible (because aluminum will not be easy, although it is possible), but definitely not glued. If the housing is removable, it would be better (more secure) with aluminum to screw it with a screw with a nut. But to the case itself, no heatsink. Don't forget that the protective conductor should also be connected to the housing of the lamp/chandelier, etc., so that it can do its job.

kolo333 · Answer

Gentlemen, thank you for your reply. You helped. The idea is still this - glue the power supply to the aluminum sheet in which there is a hole, and screw the eyelet (grounding) to this hole. Of course, glue, which also conducts electricity. This is what this diode looks like (30mmx30mm): I can't connect it to ground. As for voltage, current, etc. 1.4A, 36V, 50W (approx.). That's what it looks like.

ryszard1955 · Answer

Couldn't you attach this power supply with a metal clamp or band and screw the protective conductor to it?

tomiok · Answer

Don't mess with gluing. It is not the diode that you have to connect to the protective conductor, but the housing in which the diode is located. Added after 48 : Yes you can.

kolo333 · Answer

This diode has no housing. She looks so real. 2mm thick and dimensions 30x30 (mm). It will be glued to the radiator (it must be cooled, after all it has 50W around). :) Sorry, it is possible to buy the case. There is an aluminum or plastic sheet, but no one connects the earth to the aluminum sheet.

kolo333 · Answer

The housing is made of a special plastic (it does not conduct electricity, but it conducts heat very well). I realize that not only aluminum conducts electricity. Copper, steel, etc. also. But just the housing of this diode does not conduct current.

Grounding Necessity and Heat Sink Compatibility for Chinese LED Power Supply (50W, 20-39V DC, 1.5A)

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