EMC-2 Compliance Information
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ELECTROMAGNETIC COMPATIBILITY
Consideration should be given to shielding the supply
cable of permanently installed cutting equipment,
in metallic conduit or equivalent. Shielding should
be electrically continuous throughout its length. The
shielding should be connected to the cutting mains
supply so that good electrical contact is maintained
between the conduit and the cutting power source
enclosure.
Maintenance of cutting equipment
The cutting equipment must be routinely maintained
according to the manufacturer’s recommendations. All
access and service doors and covers should be closed
and properly fastened when the cutting equipment is in
operation. The cutting equipment should not be modified
in any way, except as set forth in and in accordance with
the manufacturer’s written instructions. For example,
the spark gaps of arc striking and stabilizing devices
should be adjusted and maintained according to the
manufacturer’s recommendations.
Cutting cables
The cutting cables should be kept as short as possible
and should be positioned close together, running at or
close to the floor level.
Equipotential bonding
Bonding of all metallic components in the cutting
installation and adjacent to it should be considered.
However, metallic components bonded to the workpiece
will increase the risk that the operator could receive a
shock by touching these metallic components and the
electrode (nozzle for laser heads) at the same time.
The operator should be insulated from all such bonded
metallic components.
Earthing of the 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
steel work, 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 in crease 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 provided
in IEC60974-9, Arc Welding Equip ment, Part 9:
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.
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