I have a LED driver which has 3 connections on the AC side , L,N and ground. In the event of power surge, can there be a difference in effect if the GND connection of the LED driver is floating or not?

for example a led driver like the one below:


In situations where the enclosure is metal, the GND connection is connected for safety measures.

But with a plastic enclosure, What is the use of the GND connection?


In the event the isolation in the high frequency transformer between the high voltage side and the low voltage side failed, a well designed PSU would use the ground connection to protect people touching the LED lights. (Usually the ground is wired directly through to the -ve side of the output)

As to your first question: "Can a power surge have a different effect on a led driver when floating?"

If there were a large common mode surge (such as is simulated in High-potential-earth testing) then the presence of an earth connection to the driver might cause it to fail, when an un-earthed driver would have been undamaged. But under such a situation the failure is to protect the devices and the people connected to the low voltage side of the driver. So having it survive, but take out the things downstream is not really a win.

  • \$\begingroup\$ are you referring to the led lights themselves or the LED drivers? \$\endgroup\$ – Navaro Jan 10 at 23:45
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    \$\begingroup\$ someone touching the lights themselves would be protected from the driver failing, as the driver can make sure the output is always near a ground potential - a driver without a ground would need to be "double insulated" in order to make a failure connecting the high voltage and low voltage very unlikely. \$\endgroup\$ – james Jan 10 at 23:49
  • \$\begingroup\$ understood, thanks can you also answer the main question whether in the event of a surge the floating GND connection can lead to a failure compared to the situation when the GND connection is not floating? \$\endgroup\$ – Navaro Jan 10 at 23:52

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