TT Zs Readings and Tripping RCD?

[R G]

The other thing is with a seized RCD is there could well be faults present but now the RCD has been released although faulty , would now mean that simply replacing it would also mean rectifying the faults too..

 

[PEG]

Only thing i could add to above,is, has leakage been clamped? and was test apparatus suitable for testing TD RCD?

 

[tony mc]

Why would you put a time delayed 30 mA units in as they are not offering additional protection for anything as they will not disconnect in time to offer this or is there something special about this instal we need to know about.

I might be missing the obvious here as I am not that bright!

 

[Sintra]

Didn't even know a 30mA time delayed RCD or RCBO existed.

 

[davesparks]

Didn't even know a 30mA time delayed RCD or RCBO existed.

They do, but I have only ever known them be made to order by specialist protection companies. I can't imagine them ever being used in anything other than a specialist installation, they aren't exactly cheap!

 

[Sintra]

They do, but I have only ever known them be made to order by specialist protection companies. I can't imagine them ever being used in anything other than a specialist installation, they aren't exactly cheap!

Yes indeed. I've had a quick search and such beasts can be ordered but surely putting these into a domestic situation for final circuits would mean that the tripping times required of 300mS @ 30mA and 40mS @ 150mA are not met.

 

[paulk11]

OK, all credibility (as if I ever had any anyway) is about to be ruined!

Having checked the info, they are standard RCDs and not time delayed!! I was going on colleagues info (honest) and not physically checked the details myself. So all advice above is much appreciated and fully understood. It's all a learning process :sick:

Cheers

 

[davesparks]

Yes indeed. I've had a quick search and such beasts can be ordered but surely putting these into a domestic situation for final circuits would mean that the tripping times required of 300mS @ 30mA and 40mS @ 150mA are not met.

Yes exactly, they are no use for shock protection.
I think they see use as a backup fault protection when 10mA protection is used. But I could be wrong

 

[Deleted member 26818]

Can be used for shock protection, not for additional protection.