Hypertherm HD4070 Rev.1 - Manual (Page 5)

ELECTROMAGNETIC COMPATIBILITY (EMC)
ii Hypertherm Plasma Systems
8-06
receive a shock by touching these metallic components
and the electrode at the same time. The operator
should be insulated from all such bonded metallic
components.
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.