This article is about DC Master Ground Busbar MGB Installation & Commissioning Checklist of DC System as per International Codes and standards.
DC Master Ground Busbar Installation & Commissioning Checklist
- Verify that the installed MGB is a copper ground bar and located within the communications equipment room. The minimum size shall be 6 mm x 102 mm x 500 mm. Make all grounding connections to the MGB using two-hole approved copper terminal lugs.
- Verify that the installed MGB meet the minimum size of 6 mm x 102 mm x 500 mm and the required two-hole for making all grounding connections to the MGB using two-hole approved copper terminal lugs are provided.
- Verify that the MGB is located as close as possible to the AC service and outside plant main distribution frame, without interfering with cable structures and support.
- Verify that the location of the MGB is identified on the building drawings and equipment layout plans, and on the bar itself.
- Verify that the MGB is bonded to the building ground grid (AC power ground) through two buried leads from opposite sides of the ground grid. The leads shall be a minimum of 4/0 AWG (120 mm²) bare tinned-copper conductors.
- Ensure that the two leads are installed in PVC conduit. When the PVC conduit is used in areas where it would be exposed to sunlight, it must be a type that is resistant to ultraviolet rays
- Ensure that bends in ground conductors are kept to a minimum on all unavoidable bends. Verify that the minimum acceptable bending radius of 300 mm for the installed sizes 4/0 AWG leads is maintained.
- Ensure that the MGB is divided to the following zones:
“”P”” surge producers (such as interior radio equipment including cable trays that are connected to radio equipment, Cable Shield/Cable Vault Ground Bar and MDF/Entrance Cable Protector Ground Bar)
“”A”” surge absorbers (both ground leads coming from the opposite sides of the ground grid)
“”N”” non-isolated equipment (DC Power system positive return bus, computer floor, communication racks and cable trays)
“”I”” isolated equipment (electronic switching equipment & transmission systems and terminal Equipment) - Verify that these zones are permanently labeled on the MGB and on the building drawings.”
- Ensure that the AC distribution system is not connected to the building ground grid through the MGB.
Standards Codes and References for DC Master Ground Busbar Installation
SAES-T-795 ” Communication DC Power System