Can cable be supported and secured by a right angle unistrut on-site made attached to a wall (like cable racks in a manhole) and/or by unistrut trapeze from the ceiling? The cables would be single conductor 500 MCM cables supplying power to high voltage magnets (1,000 VDC-1,800 VDC / +500/-500 to +900/-900 VDC). The cables would be located in a tunnel to where the tunnel is only accessed when the cables are de-energized and also the system has ground fault protection and overcurrent protection. This installation would be at a R&D site for the Department of Energy. The main question, is this type of cable support system recognized by the NEC and/or does this situation even fall under the jurisdiction of the NEC. If not what jurisdiction would it most closely fall under (NESC, IEEE, ...)? Thanks.
unistrut tray
- Thread starter kujawa
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SurfSide EC
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- Newport, NC
Don't take this the wrong way, but that sounds like a pretty heavy duty job to not have those kind of decisions/designs on print.
SurfSide EC
Member
- Location
- Newport, NC
Or are you questioning the design?
John Arendt
Senior Member
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- New Jersey
DOE/Federal jobs should have ALL (full) spec. If not, or if you are questioning the intent, speak to the EE/PE who did the prints/spec. DOE/Fed spec are more stringent than NEC most times.
John
John
Cables are generally required to be installed in a raceway or conduit. I wouldn't just string them over unistrut unless I was sure its allowed.
My guess is that you are going to have to brace those cables pretty well to keep the magnetic force from the current flow from moving them around.
Steve
My guess is that you are going to have to brace those cables pretty well to keep the magnetic force from the current flow from moving them around.
Steve
hardworkingstiff
Senior Member
- Location
- Wilmington, NC
kujawa said:
Will you elaborate on this? How are you making the right angle?
Some of the unistrut companies (at least B-Line) make "maple cable blocks" that go around the cable, and are held to the strut with a strut strap. I've never seen them used, but maybe and app like this is what they are meant for. Seems like you would use cable tray for something like this, and go with lacing all the cable down. There are some telephone CO guys around here that work on high amperage DC plants that could give you more details on this. If I remember there are some weird lacing techniques and names...
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