It can vary depending on what make you get. But all S types should trip out no less than 300ms to allow discrimination between the 30ma RCD and no more than 500ms to keep within 7671. Hagar is normally about 350ms and the last MK one I installed tripped out at 497ms
A bit off subject, what sort of values do you get when testing earth rods/tapes etc for Ze for your area?
It really can vary on the ground itself. Clay, sand, granite. Last 2 I done I got around 11 for one on the 1st attempt. Another I spent half the day just getting it to about 45.