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Street Lighting - Electrical Inspection and Testing Procedures

Associated with New, Upgraded, Rewired or Refurbished Installations

Street Lighting

Index:


General

  • The following procedures shall be undertaken for all new, upgraded, rewired or refurbished road lighting or sign lighting installations. The testing of the internal wiring within road lighting and sign lighting columns shall be performed as an integral part of the installation process. All inspection and testing must be so arranged to ensure that no danger to persons or property, or damage to equipment can occur even if the circuit tested is defective
  • All testing shall be in accordance with the requirements of BS7671 for electrical installations.


Base Compartment Electrical Earthing

Carry out all electrical earthing in the base compartment in accordance with the specification including column door, column shaft and fitting of dedicated earth block together with a main earth conductor that should be prepared ready for connecting to the incoming electricity supply.


Visual Inspection of Internal Wiring

Visually inspect to ascertain that no damage has occurred to any cable during the above installation process, rectifying any faults or damage by complete replacement prior to proceeding to the electrical testing as set out below.


Electrical Test Equipment

All test equipment shall be permanently marked with a unique identification number. The Contractor shall keep calibration certificates at the intervals recommended by the equipment manufacturer. If requested the Contractor shall furnish the Authority with copies of the above calibration certificates.


Electrical Testing of Internal Wiring

The Electrical testing described below must be carried out, such that immediately after installation the equipment can be deemed to be electrically safe and ready for connection to a suitable electricity supply.


Continuity of Conductors

The continuity of all conductors shall be tested in accordance with the requirements of BS7671.


Insulation Resistance

Insulation resistance shall be tested in accordance with the requirements of BS7671.


Final Assembly of Lanterns and further Visual Inspection of Internal Wiring

After the above tests are completed and assuming that the results are satisfactory the cable may be permanently connected and a final visual check for polarity and security of electrical connections made prior to the lantern being fully assembled complete with lamp and photo electric cell unit. The Contractor shall leave in the base compartment a “tag” as specified in the Electrical Inspection & Testing Certificate Type A and Type B, (specimens of which can be downloaded) marked, with indelible ink, to indicate the readings from the insulation resistance and continuity tests for internal wiring.


Electricity Supply

It is appreciated that in most cases where the lighting or sign column is to be provided with a direct District Network Operator (DNO) service there will not be an electrical supply installed in the lighting or sign column at this stage of the works. The Contractor shall in these circumstances complete the above checks and leave the installation in a state compliant with the provisions of the Final Assembly of Lanterns standards. Subsequent completion of the test results as detailed below will be required once the DNO supply has been installed.


Local Authority owned Underground Cabling Systems

Where electricity supplies for street furniture are not derived directly from a DNO service, underground cabling together with associated switchgear and fusing arrangements shall be inspected and tested in accordance with BS7671 and the results recorded as detailed in the Electrical Inspection & Testing Certificate Type A and Type B, (specimens of which can be downloaded)


Visual inspection including

  • Connections of conductors - for polarity, loose termination’s, excessive removal of conductor insulation resulting in bare conductors protruding from terminations
  • Appropriate identification of conductors such as switch wires from photo-electric cell units
  • Verification that the installed equipment is as designed and specified in the contract and on the drawings including Cable types and cross sectional areas
  • Presence of barriers to meet IP2X to provide protection against direct contact
  • Presence of appropriate types and sizes of earthing and bonding conductors with mechanically and electrically sound connections
  • Appropriately rated protective devices
  • Labelling of circuit fuses and isolators
  • Adequate access to equipment to facilitate safe and practical maintenance
  • Presence of ‘Danger 415V’ 400V’ notices where applicable
  • Presence of appropriate devices for isolation and switching.


Continuity and Polarity of Conductors

The continuity and polarity of all conductors within the underground cabling system shall be tested in accordance with BS7671. The results of the above tests shall be recorded on Certificate type A as per the sample illustrated in the Electrical Inspection & Testing Certificate Type A and Type B, (specimens of which can be downloaded)


Insulation Resistance

The insulation resistance of all underground cables shall be carried out in accordance with the requirements of BS7671.


Polarity

This shall be visually checked on both the incoming supply and the fused side of the terminals and tested with a polarity tester.


Earth Fault Loop Impedance

  • Earth fault loop impedance tests shall be carried out in accordance with the requirements of BS7671 and all test results recorded on a “Certificate type A” as detailed in the Electrical Inspection & Testing Certificate Type A and Type B, (specimens of which can be downloaded)Where these tests are carried out on local authority owned underground cables, the highest value recorded within each circuit must be recorded on ‘Certificate Type B” together with the location at which this ‘highest’ reading was taken. This reading must be taken into account when determining the type and rating of the protective device intended to protect the circuit and must be such that the magnitude of current flowing under fault conditions would be sufficient to provide disconnection within 5 seconds.


Type and Rating of Protective Device

  • The contractor will ensure that an appropriate type and rating of fuse or other protective device is fitted to the circuit giving due regard to
  • Discrimination
  • Protection of the equipment and all associated wiring
  • Starting currents associated with discharge lighting where applicable
  • The results of the foregoing tests.


Unsatisfactory Results and Non-compliance

  • In the event of any test result failing to comply, that test and all those preceding, the results of which may have been influenced by the fault indicated, shall be repeated after the fault has been rectified
  • No installation shall be connected to a live electrical source unless the person carrying out the inspection and testing is entirely satisfied that the complete installation complies with the requirements of BS7671. In the event that the installation is deemed to contravene these regulations the person carrying out the inspection and testing shall take all reasonable steps to ensure that the installation cannot be commissioned by any other persons
  • Such steps may include:-
    • double or triple pole and neutral isolation from any live source;
    • locking off of isolators;
    • removal of fuse links;
    • disconnection of main tails;
    • labelling adjacent to the incoming supply terminals using such wording as “THIS INSTALLATION HAS BEEN DEEMED TO CONTRAVENE THE WIRING REGULATIONS AND MUST NOT BE CONNECTED”.


Commissioning

Only when the Contractor is entirely satisfied that the installation is mechanically and electrically safe shall he energise any underground cabling system and/or lighting/sign column or bollard and check that the equipment is functioning correctly.


Certification