Residual Current Device (Rcd) Or Ground Fault Current Interrupt (Gfci) Testing - Megger MFT1800 Series User Manual

8. Residual Current Device (RCD) or Ground Fault Current Interrupt
(GFCI) testing
NOTE : The MFT1800 series can perform the following RCD tests:
1/2I Non-tripping test at half the rated RCD trip current for 2 seconds, during which the
RCD should not trip
I Tripping test at the rated RCD trip current. The trip time will be displayed
2xI Tripping test at 2 x the rated RCD trip current (Only available on MFT 1825 and 1835 instruments)
5I Tripping test at 5 x the rated RCD trip current. The trip time will be displayed in milliseconds.
0 or 180° Some RCDs are sensitive to the polarity of the supply, i.e whether the test current is applied
with the instantaneous rising or falling. Tests should therefore be performed with the polarity
0° and 180° and the maximum time recorded.
RampTest Used to check the trip current of an RCD.
Fast Ramp test This comprises a shorter test using fewer current steps compared to the standard ramp test.
Allows significantly more tests in a given time.
The MFT1800 series can test the following RCD types:
Model Type AC
MFT1825

MFT1835

MFT1845+

A Programmable RCD is typically a type A RCD with variable disconnection time. RCD's are also available with a
Selective (Delayed) trip time. These are referred to as Type S. These RCDs do not trip instantly, allowing ordinary type
RCDs to trip first.
www.megger.com

Residual Current Device (RCD) or Ground Fault Current Interrupt (GFCI) testing

Type A Type S Type B
  
  
  
EV RCDs 3 phase RCD Programmable RCDs
 



MFT1800 series 37