FreddyNurk
Electrical
- Dec 21, 2005
- 939
Hello all,
I have an interesting situation at a site where I am supervising the construction of a mineral processing plant. WE have an incoming 22kV 3 phase supply and an 8 cubicle MV distribution board, with the bus being rated at 1250A continuous, and 25kA 3 second fault rating.
After numerous discussions with the switchgear manufacturer (who shall remain nameless) who originally supplied an arc dissipation tunnel to go over the top of the switchgear, we now have a query as to whether or not the roof (floor to ceiling) height is adequate.
When we queried the manufacturer for drawings for assembly of the tunnel structure, we were informed that the tunnel was incorrectly supplied and was not type tested for our switchgear and therefore couldn't be used. We also received a query from the manufacturer asking about our roof height over the switchgear. When we responded (the floor to ceiling height is 3.2m) the switchgear manufacturer stated that it wasn't adequate and that we required a minimum of 4m. At this point we had already constructed the building and installed the switchgear, and thus were reluctant to change it unless necessary.
In accordance with this, our design engineer stated that as the prospective fault current from the supply was very low (2.4kA) that it wasn't an issue that the roof was that low and that it would be acceptable. The manufacturer maintains the stance that the roof height must be 4m as this is the height it was type tested at.
Can anyone comment as to the validity of the statement from our design engineer that we will be ok? I'm rather reluctant to trust such a perspective as I believe apart from the obvious safety aspect, that its something that would be a liability in the future for the client if anything should happen.
I await your comments.
I have an interesting situation at a site where I am supervising the construction of a mineral processing plant. WE have an incoming 22kV 3 phase supply and an 8 cubicle MV distribution board, with the bus being rated at 1250A continuous, and 25kA 3 second fault rating.
After numerous discussions with the switchgear manufacturer (who shall remain nameless) who originally supplied an arc dissipation tunnel to go over the top of the switchgear, we now have a query as to whether or not the roof (floor to ceiling) height is adequate.
When we queried the manufacturer for drawings for assembly of the tunnel structure, we were informed that the tunnel was incorrectly supplied and was not type tested for our switchgear and therefore couldn't be used. We also received a query from the manufacturer asking about our roof height over the switchgear. When we responded (the floor to ceiling height is 3.2m) the switchgear manufacturer stated that it wasn't adequate and that we required a minimum of 4m. At this point we had already constructed the building and installed the switchgear, and thus were reluctant to change it unless necessary.
In accordance with this, our design engineer stated that as the prospective fault current from the supply was very low (2.4kA) that it wasn't an issue that the roof was that low and that it would be acceptable. The manufacturer maintains the stance that the roof height must be 4m as this is the height it was type tested at.
Can anyone comment as to the validity of the statement from our design engineer that we will be ok? I'm rather reluctant to trust such a perspective as I believe apart from the obvious safety aspect, that its something that would be a liability in the future for the client if anything should happen.
I await your comments.