7 Electrical Work Permit
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ahadinreallife7 Electrical Work Permit
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ahadinreallifeMaintenance requirement for ships electrical equipment
Guideline for electrical plant on board
: With all types of electrical equipment cleanliness is essential for good
operation. Electrical connections must be sound and any signs of sparking
should be investigated. Parts subject to wear must be examined and
replaced when necessary. The danger from a.c. equipment in terms of
electric shocks is far greater than for similar d.c. voltages. Also a.c,
equipment often operates at very high voltages. Care must therefore be
taken to ensure isolation of equipment before any inspections or
maintenance is undertaken.
The accumulation of dirt on electrical equipment will result in insulation
breakdown and leakage currents, possibly even an earth fault. Moisture or oil
deposits will likewise affect insulation resistance. Regular insulation
resistance measurement and the compiling of records will indicate the
equipment requiring attention. Ventilation passages or ducts may become
blocked, with resultant lack of cooling and overheating. Oil deposits from a
direct-coupled diesel engine driving an open generator (usually d.c.) can
damage windings and should therefore be removed if found. Totally enclosed
machines should be periodically opened for inspection and cleaning since
carbon dust will remain inside the machine and deposit on the surfaces.
Brushgear should be inspected to ensure adequate brush pressure and the
springs adjusted if necessary. New brushes should be 'bedded in' to the
commutator or slipring shape with fine glass paper. Sparking at the
commutator will indicate poor commutation. This may require polishing of a
roughened commutator surface. The mica insulation between commutator
segments may require undercutting if it protrudes, or simply cleaning if
deposits have built up.
Control equipment, such as starters, will require attention to contacts which
may be worn or pitted as a result of arcing. Contactors usually have a
moving or wiping action as they come together. This helps clean the surfaces
to provide good electrical contact, and also the arc produced during closing
and opening is not at the finally closed position. The contactor contact
surfaces of frequently used equipment should therefore be subject to regular
inspections.
Safety precautions
Work on electrical systems and equipment is considered a specialised work
and must be undertaken only by qualified personnel from the ship’s staff or
shore contractors. Work on electrical equipment in an area where an
explosive atmosphere may be present requires special precautions and
permission of the Master. He shall ensure that qualified persons are doing
the work, in compliance with regulations in force and with adequate safety
precautions in place. The Master shall ensure that personnel are supervised
and all measures are taken to avoid any accidents or injuries from such
work. Reference is to be made to the relevant sections of the Safety and
Environmental Procedures.
Work Performance
Whenever work is to be carried out on electrical equipment, or on equipment
powered by electricity, in a gas dangerous zone, the electrical supply of the
equipment has to be isolated. Warning signs must be posted adequately. The
use of portable electrical equipment or wandering leads is prohibited unless
the zone is gas free for hot work and a hot work permit is issued. Intrinsically
safe equipment shall be used within their maker’s parameters and company
regulations only.
Cold Work on Electrical Equipment
Work shall not be carried out on any apparatus or wiring, nor shall any
flammable – proof or explosion-proof enclosures be opened, nor the special
safety characteristics provided in connection with standard apparatus be
impaired, until all voltage has been cut-off from the apparatus or wiring
concerned. The voltage shall not be restored until work has been completed
and safety measures have been fully re-instated.
Hot Work on Electrical Equipment
A Hot Work Permit (SAF04) must be issued as per company regulations. Work
is permitted provided that the area has first been made safe and certified
gas free and no hazardous situation exists – such safe situation should be
maintained in that condition as long as the work is in progress. No such work
shall be left unattended or without supervision. All regulatory and company
safety precautions shall be taken.
High Voltage Systems (Defined here as Voltages exceeding 1000
volts)
All maintenance and testing of high voltage equipment must only be carried
out by qualified staff, strictly in accordance with the Company Safety
Regulations and the Permit to Work documentation must be completed prior
to commencement of any maintenance.
Work by Contractors
The Master shall ensure that whenever contractors are employed, they must
be qualified professionally for the work. Arrangements must be such that
their understanding of and compliance with all safe working practices are
ensured and that they are fully qualified to do the work effectively and they
are supervised and controlled by an officer. Checks must be made regularly
to ensure that work is being done professionally, that time is not wasted and
that correct spares and materials are used when required.
Verification
It is of vital importance for the safe execution of the work on electrical
equipment and fittings comply with all regulations and recommendations in
force. The materials used shall conform to the regulations and certification
provided where applicable.
Circuit Breakers
Main Circuit Breakers are to be clearly labelled to ensure that engine room
staff do not inadvertently trip or try to close an incorrect circuit breaker.
Documentation
The planning for electrical work in a gas dangerous zone including safety
precautions taken, shall be recorded in the log book and by use of the
company Hot Work procedures, checklist and certification.
Checklist for Electrical work on High Voltage Equipment (over
1000V) for shipboard maintenance
Shipboard electrical maintenance operation involve many hazards and
careful consideration will need to be made for safe planning and execution.
Summarized below are some basic check items prior doing any electrical
maintenance job. These procedures are only indicative, not exhaustive in
nature and one must always be guided by practices of good seamanship.
Checklist for Electrical work on High Voltage Equipment (over 1000V) (to be
completed by responsible person)
Has pre-meeting been held and personnel clearly instructed of work scope,
procedure and precautions?
Are working personnel aware that some circuits in the equipment may by on
even if power supply is off?
Is integrity of cords of portable lamps and electrical tools confirmed and are
they properly grounded?
Are personnel carrying out the work, aware of the measures to be taken to
treat electrical shock?
If handling electrolytic liquid, are anti-acid gloves, apron, protective eyeware
etc available?
Have other permit to work systems been followed as necessary?
Is the concerned equipment dead and isolated from the system?
Isolation points: Have circuit main earths been applied to the equipment?
Application points: Have safety locks been fitted?
Locations/Lock set identities: Have caution/danger notices been applied to all
isolation points and safety signs appropriately positioned?