Ask the experts/Technical
Fully charged The firefighter’s switch A firefighter’s switch is an essential safety device that is provided to ensure that parts of an electrical installation designed to operate at a voltage higher than low voltage, such as a supply to a petrol station, can be readily isolated in an emergency.
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his article highlights the need to check the condition and confirm the operation of each firefighter’s switch during periodic inspection and testing of an electrical installation. In accordance with Regulation 537.6.1 of BS 7671, a firefighter’s switch should be installed in the low voltage side of a circuit that supplies: • exterior 1 electrical installations operating at a voltage exceeding low voltage, and • interior discharge lighting installations operating at a voltage exceeding low voltage. Consequently, where a periodic inspection and test is carried out on an installation that contains a firefighter’s switch, NICEIC will assume that the condition and operation of the switch has been assessed against the requirements of BS 7671 unless a valid reason for omitting it from the periodic inspection and test has been agreed with the client and recorded clearly on the Electrical Installation Condition Report (EICR). As a minimum, the condition of each firefighter’s switch should be checked, and a functional test performed to confirm satisfactory operation of the device. In some cases, the inspection and testing
Fig 2 Firefighter’s switch
1 Regulation 537.6.1 does not deem a temporary electrical installation forming part of an exhibition in a fixed building to be an exterior electrical installation.
Fig 1 Firefighter’s switch installed to provide a means of switching off the high voltage sign in an emergency
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may be limited by the extent of the work agreed with the client. This may be the case where the firefighter’s switch is maintained by a third party, for example, the emergency switch may be maintained by the contractor who maintains the high voltage part of the installation, such as the high voltage neon signs. However, where this is the case the inspector should ensure that such information is recorded on the EICR, especially as neglecting to do so may leave the installer open to future claims of liability. Requirements of BS 7671 Requirements for the provision of a firefighter’s switch are contained under Regulation group 537.6 and summarised as follows: • Provision of firefighter’s switches The firefighter’s switch should be connected in the low voltage circuit supplying exterior electrical installations, including the installation of a covered market or shopping mall, or internal discharge lighting installations (including luminous tube signage) operating at a voltage exceeding low voltage. A firefighter’s switch is not required for discharge lighting where the high voltage is only present during the starting period of the discharge lamp. In addition, a portable discharge lighting luminaire or a sign having a rating not exceeding 100 W, which is supplied from a socket-outlet are excluded from the requirements of Regulation 537.6.1 Preference should be given to providing a single firefighter’s switch to control every low voltage exterior electrical installation operating at a voltage exceeding low voltage within a single premises, and a single firefighter’s switch to control every internal discharge lighting installation operating at a voltage exceeding low voltage within a single premises (Regulation 537.6.2. refers). Furthermore, where both interior and exterior discharge lighting installations exist within a single premises they should be controlled separately. • The location and position of a firefighter’s switch Regulation 537.6.3 gives specific requirements for the siting of firefighter’s switches and associated advisory notices, which may be summarised as follows: • for an exterior installation, the switch should be mounted outside the building and its function, either on account of its position or by the posting of appropriate notices at both the installation and switch, should be clear • for an interior installation, the switch should be in the main entrance to the building, unless an
Winter 2015-2016 Connections
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