Operation Manual

42 GMC-I Messtechnik GmbH

PE Resistance

Application

Continuity and resistance of the protective conductor must be

measured.

Definition

Protective conductor resistance is the resistance of the

connection of a safety class I device (SC1) between any exposed

conductive parts and the protective contact at the mains plug or

the mains side end of the permanent connection.

Protective conductor resistance is the sum of the following

resistances:

•

Connector cable or device connector cable resistance

• Contact resistance of the plug and terminal connections

• Resistance of the extension cable

Measuring Method

Resistance is measured:

• Between each exposed

conductive part of the housing

(probe

contact) and the earthing contacts at the mains and the device

plug (if a removable mains connector cable is used), or the pro-

tective conductor terminal for permanently installed devices.

• Between the earthing contacts at the mains plug and the earth-

ing contacts at the device plug for

device connector cables

• Between the earthing contacts at the mains plug and the

earthing contacts at the coupling socket for extension cables

Parameters

The following parameters must be set before measurement:

• Measuring range: m,  or auto (automatic switching

amongst the ranges).

• Zero point: see “Combined Test – Differential Protective Con-

ductor Resistance” on page 45.

• Ip (protective conductor test current): 50, 100, 150, 200 or

250 mA

• Frequency: 48 Hz, 58 Hz, 108 Hz, 148 Hz, or 198 Hz

• Measurement duration: 5 s, 10 s, 15 s, 30 s or continuous

• Measurement type:

– Test socket (connection of SC1 devices)

– Permanent connection

– Extension cable (via test socket and probe)

In order to select the correct type of connection:

Select the measurement type and check the associated wiring

diagram after accessing it with the help function.