SPECIFICATION FOR LV FINAL DISTRIBUTION BOARDS

PART 1 - GENERAL

1.01 DESCRIPTION

A. This section covers the manufacture, furnish, installation and testing of all equipment, accessories and materials required for the installation of LV Final Distribution Boards rated upto 250 Amps.

1.02 APPLICABLE CODES AND STANDARDS

A. The work shall be carried out in accordance with this specification, the contract drawings and the standards listed hereunder.
The following codes and standards provide an acceptable level of quality for materials and products:
1. SASO 1611 Saudi Standard for Low Voltage Distribution Boards
2. IEC 60439-3 Low voltage Final Distribution Boards.
3. IEC 60529 Degree of Protection provided by the encloure (IP Code)
4. IEC 60947-2 Low Voltage Switchgear and Controlgear – Circuit breakers.
5. IEC 61008-1 Residual Current operated Circuit Breakers without integral Overcurrent Protection (RCCB’s)
6. IEC 61009 Residual Current operated Circuit Breakers with integral
Overcurrent Protection. (RCBO)

1.03 QUALITY ASSURANCE

A. All materials and products shall be new, sound and uniform in quality, size, shape, color and texture and shall be free from defects.

B. The contractor shall be responsible for ensuring that the required standards of quality control as mentioned in relative sections are maintained for the proposed Distribution Boards.

C. The supplier shall provide proof of application of a quality procedure in the manufacturing facility complying with standards. This means:
1. use of a quality manual approved and signed by a management representative,
2. regular updating of this manual so that it reflects the most recent applicable quality control procedures,
3. ISO 9002 certification.

PART 2 - PRODUCTION

2.01 GENERAL

A. These specifications apply to LV Final Distribution Boards rated upto 250 Amps.
B. The Distribution Board and the associated Switchgear and Controlgear like Circuit Breakers, Contactors, Switches, etc. should be from the same manufacturer.

2.02 TECHNICAL CHARACTERISTICS

A. The Distribution Boards shall be designed and tested for the following electrical values:
1. Rated Insulation Voltage 690 V AC.
2. Rated Operating Voltage 415 V AC.
3. Frequency 50/60 Hz.
4. Busbar rated current upto 250 Amps. (or as indicated on the drawings)
5. Short-time withstand current 17 kA RMS for 200ms.
6. Peak Short Time withstand 34 kA
7. Degree of protection (IP) IP31 as per IEC 60529


2.03 CONSTRUCTION AND OPERATION

A. Metal enclosure of the low-voltage distribution board shall be made of electro galvanised steel sheet metal without any welding Points which shall have received an anti-corrosion coating (hot polymerised polyester/epoxy powder).
B. One central slotted hole should be provided to ease accurate levelling of the distribution board.
C. Additional slotted holes for ease at wall fixing should be provided.
D. The front face of the switchboards shall be removable to facilitate servicing.
E. Removable gland plate should be available at the top and the bottom of the distribution board
F. Cable knockouts should be available on sides, top and bottom of the distribution board for quicker and easier installation.
G. Main busbar should be made of tin-plated copper and fully shrouded.
H. Main busbar, in vertical position, should be installed into a rigid and adjustable suspended pan assembly.
I. In order to provide easy connection and maximum cable space, split neutral bars should be provided as standard in both sides.
J. Earth bar should be provided as standard.
K. Number of holes per terminal bar should not be less than the number of outgoings.
L. Switchgear and controlgear should be of DIN installation type.
M. Switchgear and controlgear connections to the busbar should be of bolt-on type.

2.04 PROTECTION AND SAFETY

A. The main busbar of the Distribution Board should be fully shrouded to prevent any accidental direct contact.

B. The split neutral busbar should be completely shrouded to prevent any accidental direct contact.

C. The Main Incoming Circuit-Breakers should provide additional Earth Leakage Protection. All the protection features of the Main Circuit Breaker, including Earth Leakage Protection, should be in full discrimination with those of the outgoing feeders (as per the relevant clauses of IEC 60947-2, IEC 61008 and IEC 61009) to minimise the isolation of a faulty part of the network.

D. All outgoing feeders to bathrooms, socket-outlets, AC units and Heaters should be provided with Residual Current Protection Devices for protection against direct and indirect contact, which should be coordinated with the Earth Protection of the Main Incoming Circuit Breaker.

E. All incoming switchgears should be suitable for isolation as per IEC 60947-2.

F. For critical loads requiring Continuity of Supply, all outgoing Branch Circuit-Breakers should be connected to the Main Bus bar by a fully shrouded OFF-LOAD Isolating Switch which should facilitate the replacement or removal of this Branch Breaker without de-energisation of the Distribution Board or any of the other adjacent Branches, and also provide complete protection against a direct contact with any energised part of the Distribution Board.

G. Keylock facility should be available in order to prevent the opening of the distribution board by non authorized persons.

H. Keylock should be field installable.


2.05 INDICATION

A. Identification labels should be provided for incoming and outgoing circuits, earth and neutral busbar.
B. Outgoer labels should be provided next to the branch circuit breakers for easy and direct outgoers identification

PART 3 - EXECUTION

3.01 WORKMANSHIP & INSTALLATION

A. Materials, products and equipment furnished by the contractor, shall be installed and all work shall be performed in a first-class workmanship manner, in conformity with the best trade practices and the printed directions of the applicable manufacturers; by skilled workers equipped to produce satisfactory results; in a safe, substantial manner so as to avoid undue stresses, rigid enough to prevent undue movement, so as to present a neat, orderly appearance and to facilitate operating, servicing, maintenance and repairing.

B. All electrical equipment shall be installed in accordance with the manufacturer's recommendations, good electrical engineering practice, and the relevant drawings and specifications.


3.02 EQUIPMENT TESTING AND COMMISSIONING

A. After the installation is complete and properly adjusted, the contractor shall conduct operating tests. The various equipment and systems shall be demonstrated to operate in accordance with the requirements of the contract documents. Tests shall be performed in the presence of the client/client representative. The contractor shall provide electric power, instruments and personnel necessary for performing the various tests.

B. The testing of all electrical equipment shall include, but not be limited to, the items below. This shall be in addition to testing specified elsewhere in this specification.
a) General equipment check.
b) Field wiring and ground system verification.
c) Equipment adjustment.