Wednesday, December 16, 2009

Switchboard electrical earthing

Following is a picture showing the earthing busbar of a main switchboard. Below the picture is a simple performance specifications for the grounding of the switchboard.
The are also two more posts on switchboard installation check and switchboard electrical tests. The latter is a general list of tests and inspections that are usually required of a major switchboard such as main switchboards and large subswitchboards.
Photo 1 - Earthing busbar of a main switchboard (MSB)
The earthing of an electrical switchboard shall be in accordance with BS 7430, and the color coding of protective conductors shall be in accordance with IEC 60646.
Switchboard earthing busbar
The switchboard earthing busbar shall be installed internally along the full length of the switchboard. The material of the busbar shall be the same as the material of the phase busbars. (See more photos: Switchboard earthing busbar.)
Equipment earth bar
Where the substation consists of 11 kV switchgears, transformers and LV switchboards, earthing copper tape shall be installed continuously along the full length of the substation.
It shall be connected to the main system earth bar at both ends using appropriate size earthing bolts with nuts and spring washers.
The earthing copper tape shall be made of hard-drawn high conductivity copper.
The cross-section of the earth bar shall be sufficient to carry the rated short-time withstand current of the switchgear for the allowable temperature rise and the time specified.
Internal branch earth connections
The branch earth connections made from the switchboard earthing busbar to the individual switchboard components shall consist of adequately sized copper strips, or green/ yellow striped PVC sheathed stranded copper conductor.
The termination lugs shall be of the compression type.
Earthing of metal parts
All metal parts of a switchboard where live components (such as relays, instruments, indicating lights etc) are mounted shall be earthed through branch connections to the switchboard earthing busbar.
Doors of the switchboard shall also be similarly earthed.
Frames of the draw-out circuit breakers shall be connected to the earthing busbar through a substantial plug type earthing contact.
Note: This anchor post, Free electric installation pictures , may contain a summary of the materials you are looking for. It can be faster than clicking through each post title at the Blog Archive. I started it long ago but never actually got around to finish it.
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3 comments:

row anco said...

Wow, amazing fact I have seen here. Its also helpful to increase knowledge about technology. electrical switchboards

row anco said...

main switchboards
is most popular Switchboard Manufacturing company in Adelaid

jerome figueroa said...


One of the tasks of an electrical switchboard is that to apportion current to each device. The amount of current allocated is based on the amount of power that is necessary for operation. Meaning, the switchboard receives a constant flow of current from a source and that current is then redirected in smaller increments to each of the attached devices, based on the current status of each. As more devices are activated, the flow of power is adjusted to allow for larger demand. If less current is required for operation, an adjustment will be made as to prevent any type of overload to the wiring or circuitry. Because of way it's setup, the quantity of power that is flowing into the switchboard must match the amount of current that eventually flows into the attached devices.