TRANSMIG 225, 255 MIG Power Source, 255 2R MIG Wirefeeder
Sep 16, 2008 11
3.02 Assessment of Area
Before installing welding equipment, the user shall make an assessment of potential electromagnetic problems in the
surrounding area. The following shall be taken into account
i) Other supply cables, control cables, signalling and telephone cables; above, below and adjacent to the welding
equipment.
ii) Radio and television transmitters and receivers.
iii) Computer and other control equipment.
iv) Safety critical equipment, e.g. guarding of industrial equipment.
v) The health of people around, e.g. the use of pacemakers and hearing aids.
vi) Equipment used for calibration and measurement.
vii) The time of day that welding or other activities are to be carried out.
viii) The immunity of other equipment in the environment: the user shall ensure that other equipment being used in
the environment is compatible: this may require additional protection measures.
The size of the surrounding area to be considered will depend on the structure of the building and other activities that are taking
place. The surrounding area may extend beyond the boundaries of the premises.
3.03 Methods of Reducing Electromagnetic Emissions
a) Mains Supply
Welding equipment should be connected to the mains supply according to the manufacturer‟s recommendations. If
interference occurs, it may be necessary to take additional precautions such as filtering of the mains supply.
Consideration should be given to shielding the supply cable of permanently installed welding equipment in metallic conduit
or equivalent.
Shielding should be electrically continuous throughout it‟s length. The shielding should be connected to the Welding Power
Source so that good electrical contact is maintained between the conduit and the Welding Power Source enclosure.
b) Maintenance of Welding Equipment
The welding equipment should be routinely maintained according to the manufacturer‟s recommendations. All access and
service doors and covers should be closed and properly fastened when the welding equipment is in operation. The
welding equipment should not be modified in any way except for those changes and adjustments covered in the
manufacturer‟s instructions. In particular, the spark gaps of arc striking and stabilising devices should be adjusted and
maintained according to the manufacturer‟s recommendations.
c) Welding Cables
The welding cables should be kept as short as possible and should be positioned close together, running at or close to the
floor level.
d) Equipotential Bonding
Bonding of all metallic components in the welding installation and adjacent to it should be considered. However. Metallic
components bonded to the work piece will increase the risk that the operator could receive a shock by touching the
metallic components and the electrode at the same time. The operator should be insulated from all such bonded metallic
components.
e) Earthing of the Workpiece
Where the workpiece is not bonded to earth for electrical safety, nor connected to earth because of it‟s size and position,
e.g. 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
direct connection to the workpiece, but in some countries where direct connection is not permitted, the bonding should be
achieved by suitable capacitance, selected according to national regulations.
f) Screening and Shielding
Selective screening and shielding of other cables and equipment in the surrounding area may alleviate problems of
interference. Screening the entire welding installation may be considered for special applications.
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