Seaward A252 User manual
A252 Portable Appliance Tester INDEX
It is strongly recommended that all sections of this manual are read and fully understood by all those
intending to carry out or supervise any activity involved in electrical safety testing using this test equipment.
INTRODUCTION..............................................................................................................................................2
Reasons for inspection and testing
Methods of construction for electrical safety
Test requirements to determine electrical safety
Safety test records
INSTRUMENT DESCRIPTION............................................................................................................................9
Controls and Indicators
APPLIANCE TEST PROCEDURES....................................................................................................................17
Precautionary Measures
Visual Inspection
Electrical Safety Verification
INSTRUMENT INTEGRITY...............................................................................................................................29
Calibration
Operation Checks
APPENDIX...................................................................................................................................................33
Useful Reference Material
Useful
Addresses
D0010024.DOC (01/01/94) Page 1 INSTRUCTION MANUAL
99 Washington Street
Melrose, MA 02176
Phone 781-665-1400
Toll Free 1-800-517-8431
Visit us at www.TestEquipmentDepot.com
A252 Portable Appliance Tester INTRODUCTION
REASONS FOR INSPECTION AND TESTING
In order to satisfy the objectives of the Electricity at Work Regulations 1989, there is a clear need for a
structured programme of continual risk assessment for each and every item of electrical equipment in the
workplace. Such a programme should be monitored through reviews of the results obtained during regular
visual inspection and periodic electrical safety testing.
The frequency of inspection and testing will depend on the type of item and the manner in which it is used -
•static electrical items, such as desk-top computers, fax machines, photo-copiers etc. which are normally
used in offices, and other low-risk sector premises, may not need to be checked and tested as
frequently as hand-held industrial power tools and the like, which, even in normal use, can be subjected
to pretty arduous operating conditions and suffer considerable mechanical stresses.
•likewise, the environment in which an electrical item is used, or stored, should be also be taken into
account - a cold, damp, workshop contributing to a higher risk than a nice dry office, for instance.
Repaired items should be subjected to thorough inspection and testing, to ensure full compliance with
original manufacturers specifications and any relevant safety standards, before being returned to service.
In order to fully assess potential risks there is also a need for a clear understanding of how construction
methods and test requirements aim to provide 'electrical' safety.
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A252 Portable Appliance Tester INTRODUCTION
METHODS OF CONSTRUCTION FOR ELECTRICAL SAFETY
To provide the user with protection against electric shock general methods of construction must ensure
firstly that all 'live' parts are insulated and secondly that should this basic insulation fail the 'live' parts are
prevented from creating a hazard to the user.
This second level of protection is achieved either by 'earthing' all accessible conductive surfaces or by
providing 'double insulation' in the form of a second insulating layer or by reinforcing the primary insulation
layer.
Earthed equipment is referred to as Class I and earthing is achieved by connecting all accessible
conductive surfaces (the tool body or outer casing and associated fixings etc.) to the supply earth via a low
impedance protective conductor, then if any 'live' part comes into contact with these surfaces the hazardous
current is drawn harmlessly to earth through the protective conductor rather than through the person
holding the tool. The protective conductor is the green/yellow 'earth' wire in standard 3 core mains supply
leads.
Double insulated equipment is referred to as Class II. All accessible conductive surfaces are additionally
insulated from internal 'live' parts and components. No 'earth' wire is present in the supply lead. All Class II
equipment is identified by a prominent square within a square symbol.
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A252 Portable Appliance Tester INTRODUCTION
TEST REQUIREMENTS TO DETERMINE ELECTRICAL SAFETY
The most appropriate way of verifying electrical safety is to carry out a series of routine safety tests that
both reflect those tests used in the manufacturing process and, particularly in the hire industry, that take
into account the effects of normal wear and tear.
VISUAL INSPECTION
It is important when carrying out routine testing to first check for signs of undue wear and tear by a
thorough visual inspection - a nick in the supply cable or a cracked casing etc can easily lead to hazardous
situations when the power tool or appliance is in use.
ELECTRICAL SAFETY
The tests to verify satisfactory 'earth bonding' and insulation levels will depend on the basic construction of
the tool or appliance - Class I (Earthed) or Class II (Double insulated) - and the original standard to which it
was manufactured, the most common British Standards being BS2769 for hand held power tools, BS3456
for general appliances and BS415 for mains operated electronic, mainly audio/visual equipment.
However, clear guidance should be sought from the manufacturer, or importer, to determine the appropriate
requirement.
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A252 Portable Appliance Tester INTRODUCTION
EARTH BOND CONTINUITY
Most type testing standards, including those referred to above, require that the earth bond resistance,
between all accessible conductive surfaces and the 'earthing' terminal within the appliance, does not
exceed 0.1 Ohm and that compliance should be checked by resistance measurement using a test current
equal to 1.5 times the rated current or to 25 Amps, whichever is greater, from an a.c. voltage source not
exceeding 12 Volts.
The test current for BS415 equipment is limited to 8 Amps due to the wide use of printed circuit tracks in the
earth bond path.
In practice, routine testing will also include the protective conductor (Earth wire) in the supply lead and the
measurement will be made between the earth pin of the supply plug and exposed metal (conductive)
surfaces on the tool or appliance.
WARNING
High current Earth Bond tests may cause damage if inappropriately applied to certain equipment. The A252
does incorporate a special low current (100mA) Functional Earth test for sensitive equipment. If in doubt,
consult the manufacturer of the item before applying any test.
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A252 Portable Appliance Tester INTRODUCTION
ELECTRICAL INSULATION
To check the insulation, between the 'live' conductors (line and neutral) and all exposed metal surfaces, a
high voltage a.c. Flash Test is applied. The voltage applied will be dependant on the construction class of
the tool or appliance -
•500V the minimum test voltage recommended by the HSE in Guidance Note PM32
•1250V for standard Class I (earthed) tools and appliances
•3000V for routine testing of Class II (double insulated) equipment (2500V for BS415 equipment)
•3750V for Class II equipment following repair or reconditioning operations.
Under normal conditions the permissible leakage current at the appropriate flash test voltage should not
exceed 5mA. However, some Class I equipment may have higher inherent leakage due to an extra long
supply lead or high capacitance suppression filtering, or a combination of the two, under these conditions
an increased acceptance level, of up to 10mA, may be permissible. For certain sensitive equipment it may
even be advisable to not apply a Flash Test but to only carry out a 500V d.c. Megohmmeter test. If in doubt
advice must be sought from the appliance manufacturer.
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A252 Portable Appliance Tester INTRODUCTION
NOTES
All safety tests must be carried out with the supply switch of the tool or appliance in the ON position to
ensure that all 'live' parts are included when checking insulation.
Some specialised equipment with heavy duty motors etc. may employ contactor or relay start switching
techniques, therefore to apply a satisfactory insulation (flash) test through such devices the contacts must
be held closed by some, safe, manual means - the advice of the manufacturer must be sought on methods
to achieve this in the least hazardous manner.
Some 'trigger' operated equipment may require the switch to be temporarily held in the ON position with
insulating tape or string - under no circumstances should it be held in by hand,
REMEMBER TO RELEASE THE SUPPLY SWITCH WHEN TESTING IS COMPLETE.
Multi - function tools and appliances must be fully tested with supply and function switches set for each
operating mode.
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A252 Portable Appliance Tester INTRODUCTION
SAFETY TEST RECORDS
The recording of test results, to provide a traceable history of equipment worthiness, can also prove
beneficial as a management tool for monitoring the effectiveness of the overall maintenance system, for
reviewing test frequencies, and for asset tracking purposes etc.
To provide a meaningful structure for such results recording, CLARE have developed a fully featured,
paper-based, TEST LOG system with full recording facilities for equipment details, test routines, checklists,
and detailed test reports. With it's easy to follow format, it provides an invaluable reference to equipment
status and is therefore suitable for most industrial / workplace applications where routine testing to a regular
schedule is required.
For data intensive applications CLARE can also offer the DATAPAT 600 system which combines a bar-
code reader, electronic data logging and a comprehensive suite of management software. Fully inter-active
with all CLARE Portable Appliance Testers the system provides easy to follow, menu-driven, routines to
guide the user through data collection and storage, transfer of data - through an integral RS232 link - to a
host PC and manipulation of data to automatically up-date, or create, records and reports.
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A252 Portable Appliance Tester INSTRUMENT DESCRIPTION
A252
PORTABLE APPLIANCE TESTER
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A252 Portable Appliance Tester INSTRUMENT DESCRIPTION
The CLARE A252 instrument is specifically designed to provide a quick and simple means of verifying the
electrical safety of most commonly found Class I (Earthed) and Class II (Double Insulated) power tools and
appliances.
With additional facilities for testing even the most sensitive of Information Technology (IT) type equipment,
the A252 is ideally suited to both industrial and office / shop environments.
The instrument is fitted with Test Sockets for both standard 240V/13Amp (BS1363A) and industrial
110V/16Amp (BS4343) connectors.
Appliances fitted with other plug styles can be readily accommodated using suitable adaptors, refer to P.15
for more details.
Accessories supplied with the instrument, including a high voltage Safety Probe, Earth Return lead and a
simple to use Appliance Fault Simulator - for checking the integrity of the fault detection circuitry - are
stored in the compartment at the rear of the instrument.
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