What trips an RCD????

[wisesparky]

Hello guys, just a quick one, What trips an RCD? is it all about electric shock? if so and all limits in the test are meet, can i hold the line???????
Many times said - you need rcd protection, but what trips it????
Sorry but would love answers, thank you.....

 

[pushrod]

good summary Wot - I'll ask if there are any more when i'm next in college (thursday)

 

[MikeCDF]

My understanding is that:
Basic insulation
Double insulation
Barriers
Out of Reach
and by Automatic Disconnection with Zs low enough to ensure timely disconnection of the fuse/RCB
were for protection against electric shock.

And that RCD's were to protect the installation against thermal effects of temperature rise caused by Earth fault currents, and provide additional protection to basic protection and auto disconnection.

PS: Agree with desertbootz about operation and what trips an RCD. Really good explanation.