RCD disconnection time?

[Chris.J]

Had a PIR done yesterday on an installation that it fed from a 7.5KVa generator. This feeds a CU through about 15 mtr of SWA.
All the "dead" tests on the circuits after the CU were ok.
But when the Hager 100A/30mA RCD was tested, it took 60msec at 30mA to disconnect.
The question is this. Is the "high" supply impedance (rel. to a DNO supply) likley to effect the disconnection time?. (Electrician was using a modern "Megger" meter).

 

[Taylortwocities]

The RCD response time does not relate to supply voltage, or supply impedance.
The test will determine if the RCD operates within the specified times for the device under test.
If its out of spec it should be changed.

 

[Lectrician]

What was the supply impedance?

 

[Taylortwocities]

More than 1666 ohms?

 

[Spark123]

60ms @ I/\n for a bog standard 30mA device is fine, as long as it trips at less than 40ms for the 5 I/\n trip. The maximum figure for a non time delay BS4293 RCDs is 200ms at its rated current, the maximum for a non TD bsen61008 or 9 device is 200ms.