18 hours ago, Crossy said:

 

In this case we do know the leakage path, it's the mains inlet filter that keeps the nasties from the switching power supply from getting into the wide world, hence the usage of the term "functional earth" it's needed for the device function correctly rather than safety.

 

 

Well you learn something knew every day.  I've seen people post on this subject before but I'd no idea that computers had an inlet fiter or dealt with earths differently.  I'd always presumed that getting a belt off anything meant an internal short.

 

One thing I found before I changed over to UK sockets was that many older Thai style sockets and switches  tend to 'leak'.  I used to often find a very low voltage (2 - 4v) on the negative side of sockets and once got a belt off a light switch.  Those faults disappeared when I changed them and completely when I went over to UK sockets.

5 minutes ago, MangoKorat said:

Well you learn something knew every day.  I've seen people post on this subject before but I'd no idea that computers had an inlet fiter or dealt with earths differently.  I'd always presumed that getting a belt off anything meant an internal short.

 

One thing I found before I changed over to UK sockets was that many older Thai style sockets and switches  tend to 'leak'.  I used to often find a very low voltage (2 - 4v) on the negative side of sockets and once got a belt off a light switch.  Those faults disappeared when I changed them and completely when I went over to UK sockets.

 

Pretty well everything Electronic now has some form of inlet filtering which will leak to earth if an earth is present.

 

Your 2-wire lappie power supplies, LED lamps, wall-warts etc. are designed not to need a functional earth, but inverter A/C, washing machines and of course desktop PCs being Class-1 (metal cased) and requiring a safety earth make use of the better 3-wire filters. All will give you a nip if you "forget" the earth.