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8.7
Ramp Test
The RCD trip current is measured by applying a test current of half the rated trip current and increasing this every 300 ms (or 500ms for
type S RCDs) from 30% to 110% of the RCD current rating. When the RCD trips, the current flowing is recorded and displayed in mA.
MAKING A MEASUREMENT
.1 Select the appropriate RCD rated current on the right hand rotary switch
30
= 30mA etc.
.2 Select the RAMP test on the left hand range knob
.3 Press the TEST button
The RCD should trip and the display will show the trip current in mA.
If the RCD fails to trip, >***mA is displayed, where *** = 110% of the nominal RCD trip currnet.
8.8
Fast Ramp Test
Fast ramp test can be selected in Setup (section 10)
The fast ramp test tests that the RCD will trip between 1/2I and 1xI of the rated RCD trip current. This allows faster testing and higher
test currents to be used repeatedly, without overheating the instrument. The duration of each ramp step is less than the 300ms required
in EN 61557. As such this test should not be used if compliance to EN61557 is required.
Testing is the same as the standard ramp test.
8.9
Type A (DC Sensitive) RCD test
‘Type A’ RCDs are sensitive to pulsed DC as well as AC fault currents, and are tested with a pulsed waveform. The RMS current is √2 x
the rated operating current of the RCD. As with the normal RCDs, these should be tested with 0° and 180° polarity.
.1 To select a Type A RCD see section 8.2
These are tested in exactly the same manner as those tested in section 8.3 to 8.6 above.
Note: Type A RCDs should be tested at 0° and 180° on 1/2xI, 1xI and 5xI
