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Argyll
Power & Electronic Diagnostics 4 Knapdale Forest Office Cairnbaan LOCHGILPHEAD Argyll Scotland PA31 8SQ +44 (0)1546 600 100(Office) +44 (0)7766 735 997 (Mobile) info@apediagnostics.com |
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Argyll
Power & Electronic Diagnostics 4 Knapdale Forest Office Cairnbaan LOCHGILPHEAD Argyll Scotland PA31 8SQ +44 (0)1546 600 100(Office) +44 (0)7766 735 997 (Mobile) info@apediagnostics.com |
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This page contains in-depth information about:
Types of
Equipment
Please note that we recommend compliance with the I.E.E. Code of Practice for In-service Inspection and Testing of Electrical Equipment.
A.P.E. Diagnostics Ltd. already test portable appliances extensively for numerous commercial organisations, from retail outlets, offices and tourist accommodation, to the demanding environments of the construction, marine and tool hire industries. We can also provide testing of individual items in domestic environments if required. Do you keep getting shocks from your vacuum cleaner or other household appliance? Put your mind at ease and invite A.P.E. Diagnostics Ltd. to test your electrical equipment to make sure it's not an electrical or potential fire hazard.
Our testing equipment can correctly compensate for tools and equipment with long power leads which might otherwise fail earth-bond testing on a pass/fail type tester. The calculations are undertaken, and test limits set by the test equipment therefore eliminating errors and “guesswork”.
(Note: If I.T. equipment is connected through trailing sockets, 4 gangs etc., A.P.E. Diagnostics Ltd., advocate disconnection and full testing of the sockets wherever practicable).
This European Directive requires that industrial machinery containing electrical components and controls must be tested for electrical safety. Fixed Electrical Installations
BS7671 Guidance Note 3 recommends periodic inspections frequencies particular to your type of building or business. Inspections are often requested on change of ownership or tenure of a building, by the new owners/tenants or their insurance companies. You wouldn’t buy a £10,000 car without an inspection – so why not protect your £100k plus investment.
As electrical systems must be inspected at various times throughout construction, it is important to contact us prior to commencement of works, to agree inspection times throughout the build. Residual Current Devices (RCDs)
RCD’s work, by measuring indirectly the leakage current, from the live conductors to earth. They are not designed to detect over-current and are not replacements for fuses or other over-current tripping devices. An RCD is essentially a mechanical device and there is no way of knowing if it will work if it develops a fault. For this reason an RCD must be regularly tested using the test button. At regular intervals, RCD’s should also be tested to ensure that they are tripping at their rated trip current and within the times set for the environment / location in which they are used. A.P.E. Diagnostics Ltd. are fully equipped to test and record that your RCD's are functioning within their specifications. Description of Equipment Types
Source : IEE Code of Practice for In-service Inspection and Testing of Electrical Equipment. Formal Visual
Inspections
Earth Bond
Testing Verification is carried out by measuring the resistance of the earth path at a voltage of less than 12V and with a current of at least 1.5 times the design current of the product (but not exceeding 25A). Most standards require that this resistance should not exceed 0.1 ohms, to ensure that sufficient current will flow through the earth path, in the event of internal live conductors coming into contact with the case, thus causing supply circuit fuses to rupture. This provides protection for the user. Functional earthing (as opposed to safety earthing) may be found on some electronic equipment where the only connection to earth is via printed circuit board tracks and is primarily intended for EMC screening purposes (e.g. the metal shells of signal connectors on IT equipment). In these cases the high current tests described above may cause damage and a lower test current, typically 100 milliamps, is used. Common faults The causes of typical earth bond failure include - loose terminals, paint around connection points being poorly cleaned off, earth wires accidentally cut or broken during assembly, missing or unterminated wires, etc. Most of these will be occasional faults but where they become persistent, investigation and subsequent improvement to operation or maintenance procedures should address the problem. Insulation
Resistance As one of a series of "core" electrical safety tests, this test is a requirement within National, European and International legislation. In application, ‘live parts’ refers to both the Line (Phase) AND Neutral paths, and these are consequently joined together to form one test point, with the other test point being the Earth (protective conductor) for Class 1 products, or outer surfaces of the product for Class 2. Product switches should also be ON to include all parts of the supply path. Earth Leakage In any domestic or industrial supply a substantial current normally flows from the Phase (or Live) conductor through the various loads - motors, heating elements etc. - returning to the Neutral conductor. This current then flows, via the Neutral conductor, to the local substation where it is bonded to True Earth. This is actually the ‘Ground’ or Planet Earth. To provide protection and screening from the Live and Neutral conductors, a third conductor, Earth, is included. In a perfect world, where conductors had no resistance and insulators had infinite resistance, the current drawn by an appliance would remain in the L to N loop and no current would flow in the Earth conductor. However, in the real - imperfect - world, the current in the Live conductor can ‘leak’, via insulation, to any other conductor. The Neutral can also become elevated to 40V above True Earth so current can also ‘leak’ from this conductor. The net result is that these ‘leakage’ currents flow back to True Earth via the Earth conductor - hence the term ‘Earth Leakage’. If the Earth conductor in a Class 1 appliance were to become disconnected then this leakage current, or part of it, would flow via the lowest impedance path to true earth. Unfortunately, this could even include the person holding or touching the appliance if they are in direct contact with the Ground. In the case of Class 2 appliances, where no Earth wire is present, the leakage current would normally flow to True Earth via the Neutral conductor. Therefore, if the Neutral conductor becomes disconnected, the leakage current will again take the lowest impedance path to True Earth - once again possibly via personnel in contact with the appliance and Ground. Flash Testing In application, ‘live parts’ refers to both the Line (Phase) and Neutral supply paths. For test purposes these are joined together to form one test point, with the other test point being the Earth (protective conductor) for Class 1 products, or outer surfaces of Class 2 products. Any function switches on the product re turned ON to include all parts of the supply path. Typical ‘type test’ requirements are for a test voltage of between 1000 and 1500V, for Class 1 products (2500-4200V, for Class 2 products). To test or not to test The view that flash testing is a destructive test is often raised in discussion. This largely originates from its use in type testing laboratories where high voltages are sometimes applied for long durations, with the intention of testing products to destruction. However, in terms of production and routine re-testing applications, there is little or no evidence to suggest that the short period flash test degrades a product, even after repeated testing. A.P.E. Diagnostics Ltd. will generally only undertake a flash test, on repaired tools, or hand tools used in the construction and engineering sectors or at your specific request. Load & Function Load testing can take many forms, from a cold resistance measurement - to ensure the correct element is fitted, to an ammeter - for checking that the product draws the right current, to a watt meter bridge - to confirm power ratings are within set tolerance bands, etc. Industry Specific Testing European directive EN 60204-1 requires that industrial machinery containing electrical components and controls must be tested for electrical safety. The description ‘machinery’ covers a vast range of products that can be found in all conceivable industries. Earth bond tests are applied by attaching an earthing lead to the Protective Earth (PE) terminal on the machine and then, applying an earth probe to those parts on the machine that should be bonded to the PE terminal. High voltage withstand tests and Insulation Resistance measurements are then carried out between the PE terminal and the Phase (Line) and Neutral conductors using a high voltage safety probe.
Lack of cleanliness and poor maintenance of the door seals can lead to leakage levels in excess of the recommended limit. Testing of the unit involves measurement of the radiation levels around the oven using microwave detection instrument to ensure compliance with the 5 mW/cm2 limit. The safety interlock switches and the door seals are inspected for any signs of damage to ensure that they function correctly and safety.
The I.E.E. recommended test frequencies are available here for download in both Excel or Browser formats.
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© 2002 - 2007. All rights reserved. A.P.E. Diagnostics Ltd. |
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We all use them every day both at
home and at work. Some people define portable
appliances as "anything with a plug on it"
which is not strictly speaking correct but it gives you a
good idea of the vast number of items that may fall into
this category.
A.P.E. Diagnostics Ltd., have
extensive experience working in the construction &
tool hire industries. As well as undertaking the
relevant testing required, our technicians can assess
whether equipment is suitable for use within a particular
environment and advise accordingly.
A.P.E.
Diagnostics Ltd. have invested in the latest technology
to ensure the safe testing of your sensitive Information
Technology equipment. We are now able to undertake
three of the most important tests without disconnecting
or even powering down your equipment thus minimising the
disruption to your business.
A.P.E. Diagnostics Ltd. can
undertake inspection & testing of industrial plant
and machinery to EN 60204-1.
A.P.E.
Diagnostics Ltd. can undertake periodic inspections of
fixed electrical installations in buildings to
BS7671:2001 IEE Wiring Regulations 16th
Edition.
A.P.E.
Diagnostics Ltd. can undertake certification of
electrical systems to BS7671 in new builds. Local
authorities will not issue a completion certificate for a
new house unless all systems within that house have been
certified.
Earth Leakage
Circuit Breakers (ELCB) or Residual Current Devices (RCD)
are electro-mechanical devices designed to switch off the
electrical supply current in the event of an electrical
fault. They can detect very small faults before they
become dangerous and are excellent additional protection
against electric shock and from fires of an electrical
nature.
A.P.E.
Diagnostics Ltd., offers Microwave Oven Leakage &
Safety testing to compliment our standard appliance
testing service. Microwave ovens provide a convenient and
safe way of cooking food in the workplace, however faults
can occur and unless periodically tested they may become
a health and safety hazard without you being aware
