especially when used at construction sites or in other severe conditions. Apart from mechanical im-
pacts, damage may also be caused by e.g. high external temperature or internal overheating due
to high current flow. Extreme temperatures are the major cause of deterioration. Therefore extension
or power supply cord should be frequently tested.
Very important part of the test is the visual examination. After the visual check is done, electrical
safety tests are to be performed. It is for the user (owner) to decide about test intervals. Frequent
testing of equipment improves their operating safety.
Electrical devices and power tools are divided into three protection classes – depending on the meth-
od employed in designing power tools to ensure their electric shock protection:
Class I - in addition to the basic insulation, all metallic parts are connected with PE protection
wire in such a manner that, in the event of insulation damage, they may not become live.
Class II – power tools without the PE protection wire, but double, or reinforced insulation is re-
quired in addition to the basic one. With proper insulation, the enclosure can also be made out of
metal.
Class III - power tools of this class are supplied by circuits with very low voltage, the value of
which may not exceed:
- 50V(AC) or 120V(DC) - in normal conditions;
- 25V(AC) or 60V(DC) - in case of more hazardous conditions;
- 12V(AC) or 30V(DC) - in case of special hazards.
PAT series testers allow to perform tests in single or in auto-test mode - a testing procedure consist-
ing of several, different test types that are subsequently carried out one after another. Manual tests
are available under button, auto tests are available under:
- measuring procedure for Class I appliances.
- measuring procedure for Class II appliances (can apply for the majority of the Class
III appliances).
- measurement procedure for IEC power cords, extension cords, and oter power
cords.
Additionally the tester allows to measure parameters of portable residual-current devices, PRCD
(stand alone portable RCDs or the ones built into extension cords, switchgears, etc.). This function is
available under button (only PAT-2E and PAT-10).
Measurement settings can be done through SET menu or by using PC software.
4.2 Manual tests
In the manual mode, all the test types supported by the tester can be performed. Press
button (LED is on) to switch between all available tests (except for PRCD and IEC
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