psychicwarrior: 
 

was it worth posting  all that @zoom , to then type “who cares about the actual trip time” .  :-)

My question that I was caring about, was in relation to the space on the EIC for "rated  time delay" and it seems reasonable to conclude that it is not really intended for s-types -  so in that respect it's sorted.

Oh yes.

Z.

If you take a modern earth leakage relay to bits, the delay is quite tightly defined either by a resistor capacitor time constant, or a micro-controllor counting clock cycles. Unless you have deep pockets it should  be a scrap one, as putting it back together is hard. There are DIP switches or twiddle knobs to set it.

Inside  an type S things are simpler,  the early ones just had a mechanical damping on the latch pull-off coil, and trip time varied with the degree of over-current, but the modern ones are closer to the analogue earth leakage relay, in using an RC delay, albeit one defined by the economics of the 20% tolerance parts bin, and some electronics and an SCR to fire a fairly sturdy actuator solenoid, these have a less variable  delay  once you get comfortably above the trip threshold.

As noted 

‘ Slower than the slowest instant trip model, and 
Fast enough to limit shock duration to less than a heartbeat’ 

was the original intention, though of course never written that way, and the spec is wide enough to accommodate all types.

Mike.

As long as it is slower than say 40mS

Perhaps because a 30mA RCD might take 150ms to trip at 100mA (according to table 3A) - it's only guaranteed to hit 40ms at 150mA.

  - Andy.

AJJewsbury: 
 

As long as it is slower than say 40mS

Perhaps because a 30mA RCD might take 150ms to trip at 100mA (according to table 3A) - it's only guaranteed to hit 40ms at 150mA.

  - Andy.

I find that most of the R.C.D.s that I test trip off at about 22mS at 30mA trip test current.

Z.

I find that most of the R.C.D.s that I test trip off at about 22mS at 30mA trip test current.

Indeed - but that's not guaranteed. If you want reliable discrimination in all (non-faulty) cases then you need to consider the worst-case conditions rather than just the common ones.

   - Andy.

missed the question. 

The max non- actuation time for a given over current, is the longest pulse of that level of earth leakage over-current you might apply and be sure you can do so without the trip process ever starting - i.e. without ever passing the point of no return in de-latching. Note that you may be able to pass a larger current for a bit longer and even after the point of no return is reached may take quite a bit longer  for the contacts to be actually open - hence the other figures.

So 

a 100ma S type  will not de-latch in 130msec at 100mA, but it may at any longer duration, and will always have de-latched and be open cct by 0.5 seconds at that fault current or higher

it  will not de-latch in 60msec at 200mA, but it may at any longer duration, and will have both de-latched and be open cct within  200ms at that current or higher

it will not de-latch in 50msec at 500mA, but it may at any longer duration, and will definitely have both de-latched and be open cct within  150ms at that current or higher

the explanation under the table is poorly worded.

Mike.

AJJewsbury: 
 

As long as it is slower than say 40mS

Perhaps because a 30mA RCD might take 150ms to trip at 100mA (according to table 3A) - it's only guaranteed to hit 40ms at 150mA.

  - Andy.

I have yet to find a good working 30mA R.C.D. that trips at more than approx. 30mS even at 30mA test current. They all turn off well within 40mS even at 30mA test current.

I like the Wylex WRS80/2. They are extremely reliable and of very good build quality.

Z.