User Manual
GMC-I Messtechnik GmbH 19
Test Standard
The following must be substantiated per DIN VDE 0100 part 600: 
2008:
– Contact voltage occurring at nominal residual current may not 
exceed the maximum allowable value for the system.
– Tripping of the RCCB must occur within 400 ms (1000 ms for 
selective RCDs) at nominal residual current.
Important Notes
•The PROFITEST MASTER allows for simple measurements at all 
types of RCDs. Select RCD, SRCD, PRCD etc.
• Measurement must be executed at one point only per RCD 
(RCCB) within the connected electrical circuits. Low-resis-
tance continuity must be substantiated for the protective con-
ductor at all other connections within the electrical circuit (R
LO
or U
B
).
• The measuring instruments often display a contact voltage of 
0.1 V in TN systems due to low protective conductor resis-
tance.
• Be aware of any bias currents within the system. These may 
cause tripping of the RCDs during measurement of contact 
voltage U
B
, or may result in erroneous displays for measure-
ments with rising current: 
Display = I
F 
- I
bias_current
• Selective RCDs identified with an   can be used as the sole 
means of protection for automatic shutdown if they adhere to 
the same shutdown conditions as non-selective RCDs (i.e. 
t
a
< 400 ms). This can be substantiated by measuring shut-
down time.
• Type B RCDs may not be connected in series with type A 
RCDs.
Note
Bias Magnetization 
Only AC measurements can be performed with the 2-
pole adapter. Suppression of RCD tripping by means of 
bias magnetization with direct current is only possible via 
a country-specific plug insert, e.g. SCHUKO, or the 3-
pole adapter.
Measurement With or Without Probe
Measurements can be performed with or without a probe. 
Measurements with probe require that the probe and reference 
earth are of like potential. This means that the probe must be 
positioned outside of the potential gradient area of the earth elec-
trode (R
E
) in the RCD safety circuit.
The distance between the earth electrode and the probe should 
be at least 20 m.
The probe is connected with a 4 mm contact protected plug.
In most cases this measurement is performed without probe.
Attention!
!
The probe is part of the measuring circuit and may carry 
a current of up to 3.5 mA in accordance with VDE 0413.
Testing for the absence of voltage at the probe can be performed 
with the U
PROBE
 function (see also section 6.1 on page 16).
7.1 Measuring Contact Voltage (with reference to nominal 
residual current) with 
1
/
3 
Nominal Residual Current and 
Tripping Test with Nominal Residual Current
Select Measuring Function
Connection 
Set Parameters for I
ΔN
S
I
ΔN
Nominal residual 
Type 1: RCD, SRCD, PRCD etc.
Nominal current: 6 ... 125 A
Type 2: AC  , A/F  , B/B+   *
EV/MI
* Type B/B+/EV/MI = AC/DC sensitive
current: 
10 ... 500 mA
Phase displacement: 0°/180°
X times tripping current:
Negative/positive half-wave
Negative/positive direct current
1, 2, 5 (I
ΔN
 max. 300 mA)
Waveform:
Connection:
without/with probe
System type:
TN/TT, IT
Contact voltage:
Time to trip:
< 25 V, < 50 V, < 65 V










