Crane Power Rail Arc Flash Calculation
Crane Power Rail Arc Flash Calculation
(OP)
Has anyone calculated or know how to calculate the arc flash levels for crane's power rails (i.e. mini-loaders or warehouse automated cranes).
My concern is that for a 800 ft long power rail, the arc flash level at the feeder connection point is not going to be the same as at the end of the rail due to difference in short circuit levels.
Then; Do I need one sticker for the whole rail? Can I calculate the arc flash using only the distance at the feeder connection? How do I model a rail in a program? (I use SKM)
My concern is that for a 800 ft long power rail, the arc flash level at the feeder connection point is not going to be the same as at the end of the rail due to difference in short circuit levels.
Then; Do I need one sticker for the whole rail? Can I calculate the arc flash using only the distance at the feeder connection? How do I model a rail in a program? (I use SKM)






RE: Crane Power Rail Arc Flash Calculation
Unless you have a very good reason not to, I would use one label for the whole rail, showing the worst case.
RE: Crane Power Rail Arc Flash Calculation
RE: Crane Power Rail Arc Flash Calculation
Your best bet may be to find a conductor with matching material and cross-section.
RE: Crane Power Rail Arc Flash Calculation
I presume the entire rail is energized (and de-energized) by a single breaker/device. If so, you cannot differentiate between one point from the other and should use the worst case. Impedance of the rail itself should not matter.
Rafiq Bulsara
http://www.srengineersct.com
RE: Crane Power Rail Arc Flash Calculation
A bigger decision is whether to model as in air or "in box". Modeling as "in box" will be conservative.
Other issues are adjusting the assumed arc gap to match the bus spacing and deciding on an assumed working distance.
Good luck.
RE: Crane Power Rail Arc Flash Calculation
RE: Crane Power Rail Arc Flash Calculation
That is a good point. The worst case could be at the other end or somewhere in between. Now challange will be to figure out the impedance of the rail!
Rafiq Bulsara
http://www.srengineersct.com
RE: Crane Power Rail Arc Flash Calculation
RE: Crane Power Rail Arc Flash Calculation