Hypertherm HPR260 Manual Gas Preventive Maintenance Program Rev.5 - Manual (Page 6)

ELECTROMAGNETIC COMPATIBILITY (EMC)
ii Hypertherm
8-06
Earthing of workpiece
Where the workpiece is not bonded to earth for electrical
safety, nor connected to earth because of its size and
position, for example, ship’s hull or building steelwork, a
connection bonding the workpiece to earth may reduce
emissions in some, but not all instances. Care should be
taken to prevent the earthing of the workpiece increasing
the risk of injury to users, or damage to other electrical
equipment. Where necessary, the connection of the
workpiece to earth should be made by a direct
connection to the workpiece, but in some countries where
direct connection is not permitted, the bonding should be
achieved by suitable capacitances selected according to
national regulations.
Note: the cutting circuit may or may not be earthed for
safety reasons. Changing the earthing arrangements
should only be authorized by a person who is competent
to assess whether the changes will increase the risk of
injury, for example, by allowing parallel cutting current
return paths which may damage the earth circuits of other
equipment. Further guidance is given in IEC/TS 62081
Arc Welding Equipment Installation and Use.
Screening and shielding
Selective screening and shielding of other cables
and equipment in the surrounding area may alleviate
problems of interference. Screening of the entire
plasma cutting installation may be considered for
special applications.