29
8.1
MAKING AN RCD MEASUREMENT
NOTES:
■
To select 0º or 180º press and release the mode button
whilst in RCD test mode
(Note: Type B is not available on MFT1815 instruments)
■
10mA and 30mA RCD’s should be tested at ½ x I, 1 x I and 5 x I
■
All other RCDs only need to be tested at 1 x I
■
I = trip current rating of the RCD
■
2 x I available on the MFT1825 and 1835 only.
■
Connecting the neutral test lead in either of the above options will not affect the rcd but will detect a reverse polarity and,
on UK products, the testing will be inhibited.
8.2
Selecting RCD type
Using the right hand (secondary range knob) select the RCD trip rating. This is printed on the RCD (10mA, 30mA 100mA etc)
Select the RCD type, either AC, A, S or B by pressing and HOLDING DOWN the mode button
for 2 seconds whilst in RCD test
mode. Repeat until the RCD type is displayed. Refer to table above for symbol options and descriptions.
Note: Type B RCD testing is not available on MFT1815.
8.3
½ x I RCD Current Rating (No-trip test)
.1 Set the LEFT rotary range knob to the
1/2 l
RCD test range.
.2 Set the RIGHT rotary range knob to current rating of the RCD under test
30
= 30mA etc.
Ensure the display shows 0º in the display (see below):
.3 Connect the instrument Phase (L1) and Earth (L2) terminals to the RCD phase and Earth terminals (or to the phase and earth of
the circuit the RCD is protecting). Use either the separate leads
or mains plug
leads.
RCD
g
L
N
E
MCB
L
N
E
MCB
g
.4 Press the TEST button.
