c.3 the test instrument must capable of
producing test voltage 250V, 500V 1000V and deliver output cur-
rent not less than 1mA its normal voltage. This will maintain the accuracy the instrument an
acceptable level, usually within the true value. Let look the
requirements four often used test meters. These devices should temporarily disconnected that they are
not damaged the test voltage of, for example, the insulation resistance
test (Regulation 612. All test equipment must chosen accordance with the
relevant parts 61557.
Definition
The test instruments and test leads
used the electrician for testing
an electrical installation must meet
all the requirements the relevant
regulations., and deliver short-
circuit current not less than 200mA (Regulation 612. During the test, the instru-
ment does Ohm’s law calculation and displays the test result resist-
ance reading.3). d.
CONTINUITY TESTER
To measure accurately the resistance the conductors electrical
installation must use instrument which capable producing an
open circuit voltage between and 24V a.c.Electrical installations and wiring systems
351
There increased use electronic devices electrical installation
work, for example, dimmer switches and ignitor circuits discharge
lamps.
The test instrument must also carry a
calibration certificate, otherwise the
recorded results may void.
Modern digital test instruments are reasonably robust, but maintain
them good working order they must treated with care. The IEE Regulations (BS 7671)
also specify the test voltage current required carry out particular tests
satisfactorily. this
and comply with Regulation 612. All testing must, therefore, carried out
using ‘approved’ test instrument the test results are valid.
EARTH FAULT LOOP IMPEDANCE TESTER
The test instrument must capable delivering fault currents high as
25A for 40ms using the supply voltage. Calibration certificates usually last for year.
Approved test instruments
The test instruments and test leads used the electrician for testing an
electrical installation must meet all the requirements the relevant regu-
lations. approved
test instrument costs equally much good-quality camera; should,
therefore, receive the same care and consideration.
. The Health and Safety Executive has published Guidance Notes GS
38 for test equipment used electricians.2.
INSULATION RESISTANCE TESTER
The test instrument must capable detecting insulation leakage
between live conductors and between live conductors and earth. The
test instrument must also carry calibration certificate, otherwise the
recorded results may void. The functions
of continuity testing and insulation resistance testing are usually com-
bined one test instrument.1).
Test instruments must, therefore, tested and recalibrated each year an
approved supplier.
Definition
All testing must, therefore, carried
out using ‘approved’ test instru-
ment the test results are valid
