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16th
Edition Inspection Testing Policies
Electrical Services Inspection and Testing Requirements
Electrical
installations in premises are common causes of fires and can also
cause injury or fatality. The majority of fires of electrical origin
occur due to defective installation, inadequate maintenance or
misuse of electrical systems and apparatus.
The
installation, use and maintenance of electrical installations are
governed by the Electricity at Work Regulations 1989 which requires
all electrical systems to be maintained to a safe standard. Periodic
inspection and testing of electrical installations at premises by a
qualified electrician can assist with compliance and should be
undertaken in accordance with BS7671 "Requirement for Electrical
Installations" (IEE Wiring Regulations 16th Edition) and supporting
IEE Guidance note 3. The frequency of the testing is dependant on
the type of premises and varies between one and ten years.
For
guidance, a typical inspection and testing will involve the
following;
| Distribution Boards and Final Circuits |
| |
| • 100% of distribution
boards undergo visual inspection |
| • 100% of distribution
boards are tested for Earth Loop Impedance and short circuit
current |
| • Approximately 10% of
lighting circuits are tested for insulation resistance
|
| • Approximately 20% of
power circuits are tested for insulation resistance
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| • 10% of the final ring
circuits are tested for insulation |
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| Lighting |
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| • A light
fitting within each circuit is tested for insulation resistance
and internal inspection |
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• |
100% of light circuits are
tested for insulation resistance and given an Earth Loop
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Impedance test at the furthest
point in the circuit |
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| • Additional
samples of 5% of all light fittings are given Earth Loop
Impedance test |
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| Mains Socket Outlets |
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| • 100% of sockets will
receive an external inspection |
| • 100% of socket
outlets will be tested for Earth Loop Impedance and polarity
|
| |
| Fixed Appliances (not operated from control
panels) |
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| • 100% of fixed
appliances receive an external inspection, 10% internal
inspection |
| • 100% of fixed
appliances are tested for Earth Loop Impedance
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| • 10% of fixed
appliances are tested for insulation resistance
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| Fixed Appliances (operated from a
control panel) |
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| • 100% of
control panels are inspected internally wherever possible
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• |
Earth Loop Impedance tests are
performed at each control panel and at each appliance |
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fed from the panel wherever
possible |
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| • A 10%
sample of electrical terminations inside control panels will be
checked for tightness |
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| Residual Current Devices |
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• |
100% of RCDs are tested for
tripping times at half rated, full rated and 5 times rated
tripping |
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current across both positive and
negative cycles |
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| Main Switchgear and Circuits |
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• |
20% of all circuits from the
main switchgear to the local distribution plant are
inspected |
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and tested for the
following; |
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• Insulation resistance |
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• Main switchgear is inspected internally
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• Cable sizes are checked for current carrying capability
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• Circuit protective devices are checked for deterioration
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• Earth Loop Impedance and prospective short circuit current
are measured |
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| General |
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• |
100% of circuit wiring is, where
possible and relevant, visually inspected |
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The inspection and
test should be undertaken by a qualified electrician or contractor,
preferably by a member of the National Council for Electrical
Installation Contacting (NICEIC), Electrical Contractor
Association (ECA) or someone approved by a UKAS/ISO17020 accredited
organisation. |
