RCD testing :)

Traineenoob · Oct 3, 2011

Hi guys i have confused myslef completly now!!

RCD test
Reason: To make sure RCD's trip within the correct time

Method: An RCD tester is connected and a test at 1/2 times, 1 times and 5 times the trip current is performed on each side of the cycle and a time of trip obtained. Usually milli-seconds with the highest being recorded. The manual test button is then pressed.

Thats right??

But what do i record in my cert? is it really the highest?

Can someone explain why im testing at 1x and 5x please i thought 5x was for additional protection but i have really confused myself...

So at 5x the disconnect time needs to be under 40ms?
and at 1x needs to be 300ms or 200ms for older type.

Think im getting confused on the cert where it asks for maxium disconection time 4s?

Thanks for the help really love this forum!

Deleted member 26818 · Oct 3, 2011

You test 30mA RCDs at 1/2 x, to ensure that the unit is not over sensitive.
You test at 1 x to ensure that the unit is operating correctly.
You test at 5 x to ensure the unit complies with Regulation 415.1.1.
The 0.4s disconnection time is now really only relevant for non-RCD protected circuits, and for those in a location containing a bath or shower when determining if supplementary bonding can be ommited.

Richard Burns · Oct 3, 2011

30mA RCDs are tested at 0.5X, 1x and 5x operating current on both positive and negative half cycles.

on 0.5 times it should not trip on either test
on 1x it should trip within 300ms on either test
on 5 x it should trip within 40ms on either test
Both of the highest values for each of 1x and 5x should be recorded.

RCDs over 30mA are tested only on 0.5x (no trip) and 1x (300ms) and the highest value from the 1x tests is recorded (usually where it is the main switch).

These timings are for modern RCDs to BSEN61008 or BS61009. There are different times for other BS no. RCDs

RCDs are tested to ensure that the appropriate disconnection time is met and that the RCD is performing the expected function.

(too slow)

Traineenoob · Oct 3, 2011

So for the cert do i record both highest reding of 5x and 1x or just the 5x readings? the rcd is not the main switch and its a 30ma split load board with 3 rcbo's

Deleted member 26818 · Oct 3, 2011

Traineenoob said:
So for the cert do i record both highest reding of 5x and 1x or just the 5x readings? the rcd is not the main switch and its a 30ma split load board with 3 rcbo's

If you are going to record the times, then yes the highest readings.
Depending on what sheets you are using, i.e. if there is one box, then just the 5 x.
If two boxes, then both the 1 x and the 5 x.
Some people just tick the boxes if they pass, some just record the readings on the first circuit covered by the RCD.
I'ts up to you.