Unusual electric shock....

Hi,

I was running a 40W offline flyback and got electrocuted by touching the drain node of the flyback……..

I am not sure I understand this since………….

1….The mains was supplied via a 50Hz isolation transformer
2….I had rubber souled shoes on.
3….I touched the drain node with a single part of my right finger….no other part of my body was in any contact with any other part of the circuit.
…and no part of my body was in contact with anything else, other than the souls of my rubber shoes, which were in contact with the vinyl floor.
4….The PCB has only Live and Neutral conductors connected to it…..there is no earth connection to the PCB connector.

This flyback is one of two converters which are powered by the input PFC stage….which is on the same PCB.

-So the flyback’s V(in) is 390V.


How could I have been electrocuted?

Current only travels in loops, and there was no loop path available through my body to complete any current loop.

Electric shocks are often via the human body acting as a capacitor to Earth ground……………but I had used an isolation transformer, so there would have been no loop through my body which goes through earth ground.

Just one (silly?) idea: are you sure it wasn't an electrostatic discharge?? The fact that you were using an isolation trafo and RUBBER shoes could point in that direction.
I saw a person electrocuted at 380V, he practically did a 5 meters jump that hurled him to the wall :shock: - he nearly survived. I hope this was not your case

Hi,

No it wasn't an ESD.

It was a definite jolt and not a "snap" like ESD.

Anyway, i cannot understand how i was electrocuted through an isolation transformer...do you know how it can possibly happen?