vantech said:

The LED driver is double insulated, and SELV and a plastic case and remote from the panel. It does stipulate in the user manual that the driver does have earth leakage, but how does this happen when it has no earth conductor, and it’s output is SELV?

It might be "double insulated" but like a laptop supply require a mains earth (cpc connection) for functional purposes.

However, there are electronic converters that don't meet the "BS 7671 requirements" (IEC 61140) for SELV or PELV, due to the replacement of BS EN 60950-1 with BS EN 62368-1, and that is why BS 7671:2018+A2:2022 has requirements in some of the Part 7 sections, such as Sections 701, 702, 710, numbered '7xx.414.4.5' saying something along the lines of 'Where SELV or PELV is used <in stated conditions> a source described in Regulation 414.3 (iv) shall not be used.'

The driver has no earth connection, only line and neutral, hence the confusion. 

The driver has no earth connection, only line and neutral, hence the confusion. 

Leakage doesn't necessarily have to be to c.p.c. - it's just the potential for some current to escape as it were -  exactly what route the current can take and what limitations there are to current flow is down to individual circumstances.

In some test arrangements things are wrapped in foil and current measurements taken from that to Earth, or tests might be from the LV to ELV sides. In some circumstances the current that can actually escape may be negligible, and the part just it there at something like half mains voltage - but almost(*) any attempt to measure the voltage will allow some current to flow and so reduce the apparent voltage (which can be very confusing in some circumstances, and measured voltages then seem not to add up correctly).

(*) there are voltage measurement techniques whereby you compare the voltage you want to measure with a known but variable voltage source (with a common earth/N connection) and adjust things until no current flows - the setting of voltage source then tells you test voltage. But not many test meters work that way.

    - Andy.

Hi Andy,

The panel light, is powered via a constant current output from the driver. The LEDs inside of the panel are isolated from the metalwork of the luminaire. 

Perhaps the leakage is via induction into the bodywork of the luminaire, via the secondary side of the driver? 

Perhaps the leakage is via induction into the bodywork of the luminaire, via the secondary side of the driver? 

Probably not induction - as you'd generally need pretty hefty currents or conductors coiled up many times to generate a noticeable voltage. Capacitive coupling or even resistive (eg.insulation not quite a good as it appears) might be more likely.

   - Andy.

Perhaps the leakage is via induction into the bodywork of the luminaire, via the secondary side of the driver? 

Probably not induction - as you'd generally need pretty hefty currents or conductors coiled up many times to generate a noticeable voltage. Capacitive coupling or even resistive (eg.insulation not quite a good as it appears) might be more likely.

   - Andy.