5.5 Nuisance trip check
5.5.1 Description
EV chargers will always be protected by a residual current device (RCD) or a ground fault circuit interrupter (GFCI).
These devices have the same function to protect the user from electrocution or to prevent fault current causing a fire.
They work by detecting an imbalance in the circuit current, if less current returns from the circuit it must be flowing
to to ground. If this ground leakage current becomes too large the RCD or GFCI will trip.
The nuisance tripping test on the EVCC300 will apply a calibrated earth ground leakage current starting at approx
half of the trip rating of the chargers protective RCD or GFCI device selected. The instrument will then increase the
current until the RCD or GFCI trips. The result will be the actual current at which the device tripped, and is displayed
in mA. Should the trip current be low this will indicate a high probability the charger will suffer from nuisance
tripping of the RCD or GFCI.
The EVCC300 can perform four different tests as follows:
230 V Ph to N (UK / Europe tests)
AC current ramp test
Test current:
Ramp up to 30 mA in 2 mA steps of 300 ms duration
Max. test time:
4.5 seconds
Test result:
RCD trip current
DC current ramp test
Test current:
Ramp up at a rate of 6 mA in 2.5 seconds
(to prevent test tripping AC response of the RCD)
Max. test time
Hold at 3 mA DC for a maximum of 11.25 seconds
Test result:
RCD trip current
120 V Ph to N (USA tests)
6 mA AC current ramp test
Test current:
Ramp up to 6 mA in 0.5 mA steps of 100 ms duration
Max. test time:
4.5 seconds
Test result:
RCD trip current
20 mA AC current ramp test
Test current:
Ramp up to 20 mA in 1 mA steps of 100 ms duration
Max. test time:
2 seconds
Test result:
RCD trip current
5.5.2 How to perform the test
1. Switch the instrument ON.
2. Ensure the mains supply to the charger is powered up and
turned on.
25
Tests
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