Switchgear Room / Substation, Equipment Installation Inspection & Notes

This article is about Switchgear Room / Substation, Equipment Installation Inspection & Notes of Electrical Power System Systems as per International Codes and standards for Commercial Buildings, Plants and Refinery Projects.

Switchgear Room / Substation, Equipment Installation Inspection & Notes

Document Review

Documentation for traceability reviewed and implemented.

Material Inspection

Equipment and Materials shall be new and unused.
Equipment and Materials shall be in accordance with the Saudi Aramco-approved project-specific design drawings, diagrams, schedules, lists, databases, and associated design documents.

Installation Inspection

  1. Check that the equipment to be installed has the approved type of enclosure. (NEC 110.2, 110.11)
  2. Check for broken or damaged parts and contamination by foreign materials. (NEC 110.12C)
  3. Check for secure mounting and adequate ventilation space for equipment. (NEC 110.13)
  4. Check adequate working clearances, dedicated spaces and headroom around equipment. (NEC 110.26)
  5. Switchgear, controlgear, switchboards, transfer switches and adjustable frequency drives shall only be installed in an air-conditioned environment.
  6. Unobstructed horizontal space for switchgear shall be:
    a) 2 meters in front.
    b) 1 meter in back and sides.”
  7. Unobstructed horizontal space for controlgear, switchboards, transfer switches and floor mounted adjustable frequency drives:
    a) 1.5 meters in front
    b) 1 meter on the sides.”
  8. Unobstructed horizontal space for panelboards and switchracks shall be 1 meter in front.
  9. Outdoor padmounted electrical equipment shall be placed on a level concrete pad elevated a minimum of 100 mm above natural grade.
  10. The following minimum clearances shall apply:
    a) A minimum working clearance of 2 meters on all sides.
    b) A minimum working clearance of 3 meters on the sides of the equipment having doors or access panels which can be opened to exposed live parts.
    c) The intent of the above requirements are met by gate(s) which can be opened to provide the required clearance.
  11. Cable shall not be used to extend the main bus of switchgear, controlgear, switchboards, switchracks and panelboards.
  12. Panelboards and dry-type distribution or lighting transformers shall not be installed within controlgear or low voltage switchgear.
  13. Panelboards shall not be installed within the controlgear.
  14. Working space of at least 1 meter shall be provided in front of each battery rack or enclosure.
  15. Battery room walls and floor shall be made of concrete construction.
  16. Battery rooms shall be provided with enclosed and gasketed (i.e., vapor tight) corrosion resistant lighting fixtures.
  17. Emergency eye wash facilities shall be provided as per SAES-B-069.
  18. Temperature in the battery room shall be maintained at, but shall not exceed, 25 degree C.
  19. Return air-conditioning ducts from battery rooms shall be prohibited.
  20. False ceilings shall not be permitted in battery rooms and ceilings shall be finished to avoid trapped pockets of hydrogen.
  21. Lighting fixtures shall be installed at least 300 mm below the finished ceiling.
  22. Passageways shall be unobstructed and shall provide a minimum 2.3 m headroom.
  23. Conductors shall enter the building through walls only. Exception: Existing substation buildings that were designed based upon the floor entry of cables and conduits.
  24. Exterior illumination shall consist of HID high pressure sodium type fixtures controlled by a photo cell.
  25. A Hand-Off-Automatic (HOA) selector switch shall be provided in accordance with SAES-P-123 requirements for exterior illumination controls.
  26. Emergency interior illumination shall be provided by one of the following:
    Sec. 6.8.1: Self-contained, battery-powered emergency lighting units, with integral charger, which are automatically energized upon loss of 120 VAC power.
    Sec. 6.8.2: Uninterruptible Power Supply (UPS) system located in the substation.
  27. Duplex, 3-wire, 20 A, 120 VAC (NEMA 5-20R) convenience outlets shall be mounted 1 m above the floor throughout the substation building.
  28. A minimum of one outlet shall be provided for each 6 m of wall space. A minimum of two outlets per substation shall be provided.
  29. Substation roof drainage shall not be to the transformer yard side of the substation building.
  30. The concrete floor in front of switchgear shall be flush with the roller level of lower breaker carriage rack and have a smooth surface to facilitate removal and rolling of breaker. This floor shall be surface hardened for rolling stock.
  31. Leveling steel beams or channels shall be provided for all switchgear and controlgear.
  32. Unless greater clearances are specified by the NEC, the following minimum clearances shall apply:
    1. A minimum working clearance of 2 meters on all sides
    2. A minimum working clearance of 3 meters on all sides of the equipment having doors or access panels which can be opened to exposed live parts.
    3. The intent of the above requirement are met by gate(s) which can be opened to provide the required clearance.
  33. For transformer containing 7570 liters and less of insulated oil: Clearance shall be per Sec 7.1 (SAES-P-119).
  34. For transformer containing more than 7570 liters of insulated oil: a) Separation from buildings i) Fire rated building; 6.1 meters or greater ii) None fire rated building; greater than 15.25 meters
  35. For transformer containing more than 7570 liters of insulated oil: b) Separation between transformers If no fire barrier of fire rating less than 1 hour: greater than a minimum of 9.1 meters of clear space per ANSI/IEEE 979.
  36. Fire barrier characteristics shall be as follows:
    1. a) not less than 300mm above the transformer tank, conservator, transformer bushing, and pressure relief vents, etc.
    2. b) shall extend at least 600mm horizontal beyond the line of sight between all points on adjacent transformers.
  37. Oil containment and/or oil drainage systems shall be provided for oil filled equipment containing more than 2,500 liters of oil.
  38. Work space and dedicated space shall not be used for storage. (NEC 110.26 B)”
  39. At least one entrance of sufficient area shall be provided to give access to working space. (NEC 110.26 C)
  40. Working spaces shall have adequate illumination. (NEC 110.26 D)
  41. In manned switchgear rooms and control rooms a minimum emergency illumination level of 100 lux (10 fc) shall be provided at 760 mm above the floor.

International Standard and Codes for Switchgear Room / Substation, Equipment Installation

  1. METHOD STATEMENT FOR TESTING & COMMISSIONING OF SWITCHGEAR
  2. Advanced Power and Energy Meters Technical Requirements
  3. Erection and Commissioning of Medium Voltage Switchgear by Suppliers
    4. SAES-P-103 UPS and DC Systems.
    5. SAES-P-116 Switchgear and Control Equipment.
    6. SAES-P-119 Onshore Substations.
    7. NFPA 70 National Electrical Code (NEC).
    8. SAES-P-123 Lighting.

 

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