Table base
Operating table OPX mobilis and OPX mobilis RC –
E
DITION
05-03-GB
ID.-Nr.: 02008857
65
Measuring the equivalent of the leakage current to ground
Measuring the leakage current on site is either impossible
or requires special effort. Normally, the measurement of
the equivalent of the leakage current is sufficient after
repairs to and modifications of appliances connected to
the mains by means of mains cable and plug.
Measurement of the equivalent of the leakage current
produces measured values which are not directly
comparable with the leakage current values according to
the definitions for type tests.
The purpose of repeated measurements of the equivalent
of the leakage current is to recognize as soon as possible
any deviations from the so-called initially measured value
and thereby, modifications of the safety structure of the
appliance.
These measurements may only be carried out by skilled
personnel, as during the measuring procedure of the
leakage current, protective measures, e. g. the protective
conductor, may be ineffective.
Measuring circuit
The measuring circuit consists of the actual measuring
device and an external circuitry. Observing the following
requirements, the circuit for measurement must be
appropriate to measure alternating currents between 10
µA and 10 mA.
The actual measuring device must display r.m.s. voltage
of sinusoidal alternating current; an input resistance of
≥
1 M
Ω
, and the error of measurement, basing on the
accumulated range value, must not exceed 5% in the
frequency range of 20 Hz to 1000 Hz.
Measuring circuit
