Tony S
Senior Member
- Location
- Resting under the Major Oak UK
This is a follow on from the discussion about AFCI?s where EFCI?s (RCD?s) and GFCI?s (RCBO?s) got included in the general mix of things.
Press the button and see if it works method seems to be the accepted way of testing.
Now I?ll ask some questions.
Do you know the response time? It could be crucial when someone receives an electric shock.
Is the test circuit within its parameters? It could very well be faulty and tripping a 10x the rated current. Would you know?
This is the accepted method in the UK:
To test RCD?s and RCBO?s there are eight tests in total. Obviously for three wire 230V there will be more tests.
Four tests using the positive wave cycle, four using the negative.
The reason for using half cycle is some RCD?s have slightly differing characteristics for each half of the wave cycle. If there?s a major difference then it is time to change the unit.
The first six tests are for response times:
A1/ 0.5 rated tripping current +ve, this should hold indefinitely
A2/ 0.5 rated tripping current -ve, this should hold indefinitely
B1/ 1.0 rated tripping current +ve, this should trip within 300 mS.
B2/ 1.0 rated tripping current -ve, this should trip within 300 mS.
C1/ 5.0 rated tripping current +ve, this should trip within 40 mS.
C2/ 5.0 rated tripping current -ve, this should trip within 40 mS.
The final two tests are for the trip threshold where the test (fault) current is ramped up in stages to determine the point the RCD actually operates at. It should be around 23mA for a 30mA unit, below that and there?s the chance of spurious trips.
D1 ramp up +ve.
D2 ramp up ?ve.
The meters used for these tests can be set for the UK standard trip currents of 10, 30, 100, 300 and 500mA. Some of the more expensive units allow you to set your own parameters.
Someone please explain to me why ?pressing the button? is the better method.
Economic reasons will not be accepted as an argument, safety reasons only please.
An EFCI works exactly the same way as a RCD. If what goes in doesn?t come out then there?s a fault. It?s not rocket science.
Press the button and see if it works method seems to be the accepted way of testing.
Now I?ll ask some questions.
Do you know the response time? It could be crucial when someone receives an electric shock.
Is the test circuit within its parameters? It could very well be faulty and tripping a 10x the rated current. Would you know?
This is the accepted method in the UK:
To test RCD?s and RCBO?s there are eight tests in total. Obviously for three wire 230V there will be more tests.
Four tests using the positive wave cycle, four using the negative.
The reason for using half cycle is some RCD?s have slightly differing characteristics for each half of the wave cycle. If there?s a major difference then it is time to change the unit.
The first six tests are for response times:
A1/ 0.5 rated tripping current +ve, this should hold indefinitely
A2/ 0.5 rated tripping current -ve, this should hold indefinitely
B1/ 1.0 rated tripping current +ve, this should trip within 300 mS.
B2/ 1.0 rated tripping current -ve, this should trip within 300 mS.
C1/ 5.0 rated tripping current +ve, this should trip within 40 mS.
C2/ 5.0 rated tripping current -ve, this should trip within 40 mS.
The final two tests are for the trip threshold where the test (fault) current is ramped up in stages to determine the point the RCD actually operates at. It should be around 23mA for a 30mA unit, below that and there?s the chance of spurious trips.
D1 ramp up +ve.
D2 ramp up ?ve.
The meters used for these tests can be set for the UK standard trip currents of 10, 30, 100, 300 and 500mA. Some of the more expensive units allow you to set your own parameters.
Someone please explain to me why ?pressing the button? is the better method.
Economic reasons will not be accepted as an argument, safety reasons only please.
An EFCI works exactly the same way as a RCD. If what goes in doesn?t come out then there?s a fault. It?s not rocket science.
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