Internal And External Connected

  • Bus plugs provide an off-load disconnectable link between the busbar system and the short circuit protective device (SCPD).
  • Bus plugs are normally mounted on a tray or mounting panel containing all the protective, switching and control equipment for a motor drive/feeder circuit.
  • The composite arrangement is then easily and safely demountable when the switchboard is alive.
  • Withdrawable units (where both the line and power connections are unpluggable) would also use a bus plug on the load side connections.

Standards and Type Tests:

AS3439-1-1993 (IEC439-1)

Low voltage switchgear and controlgear assemblies.
This is the test standard when the bus plug is used as a part of the switchboard assembly. Numerous test have been carried out as prescribed in clause 8 of the standard. These test include:

  • Temperature rise
  • Dielectric properties
  • Clearance and creepage distances
  • Short circuit strength to 63kA in conjuction with HRC fuses and moulded case circuit breakers for both motor circuit and feeders
  • The bus plugs have also been included in numerous fault containment test (to appendix EE) up to 63kA prospective for motor drives and feeder circuits with fuses and moulded case circuit breakers

AS3934.3-1994 (IEC 947 Part 3)

Low voltage switchgear and controlgear.
Part 3: Switchgear, disconnectors, switch-disconnectors and fuse-combination units. This standards applies when the bus plug is installed as an integral part of the short circuit protective device.
Tests carried out under Clause of this standard are to prove the short-circuit strength of the plug and connections to the SCPD (fuse combination units and moulded case circuit breakers). Fault currents S0-63 kA depending on the rating of the SCPD.