11KVA Power Cable Interference

[aws04]

We are installing a CNC laser cutting machine &
there is 11KVA power cable running under our workshop
about 600mm to 1000mm under the floor. Is it possible that this could interfere with the machine . The cnc control cabinet would be not directly over the cable but the servo motors & other cables would travel over the cable when cutting down that end of the machine.Is it possible to estimate or measure if this may cause interfence or not
Would putting a earthed steel plate 1000mm wide in the floor along where the cable is help ?

Steve C

 

[ruggedscot]

Interference on an 11kv cable....

well you have to think about fields here, current flows through the cable produce the fields and as you can imagine at 11kv the current flow is pretty small compared to say a service cable running at distribution 240/415v 3ph. Id say go with the metal plate as a cover and as the 11kv cable has all the cores close the interference problem should not materialise. take it that the cable is suitably screened and covered at present ?

Rugged

 

[Bung]

Shouldn't be a problem at all. If the machine can't handle what little interference might be present from the 11kV cable, I doubt that it would handle the interference from the rest of the machinery in the shop. It will have a fair amount of emc withstand capability by design.




Bung
Life is non-linear...

 

[Skogsgurra]

It is good that people are alert and try to think about possible problems when new equipment is planned for. But you can forget about the 11 kV cable altogether. The magnetic interference is close to nil and the electrostatic field does not get outside the cable screen. Rugged and Bung are absolutely right.

And, please: If there should be any problem with this new installation - don't blame the cable. I have seen otherwise perfectly sound people blocked and passivated by exactly such things. Instead of finding out where a shaft jams or the alignment is bad they blame something that has nothing to do with the problem. Like your cable.

 

[aws04]

Thanks all,
I was really concerned about putting the machine over this cable - it's looking like it won't be a problem !!
steve

 

[busbar]

Just use a little restraint drilling anchor holes in the floor. ;-]