ME466 HV AP Revision Questions Flashcards
Recall key facts of HV knowledge and procedures for written assessment
- APC Handover should cover
SPEKS
Status - of HV system, Dead/Live,
Permits, Switching Schedules, Sanction for Test in force
Earths - any CME/Additional earths on system and visit
Keys - muster master keys and sign in SR
Sign - for handover in SR
- What are the Golden Rules
DIE CPR
Disconnect
Isolate
Earth
Cordon
Point of work identified and proved dead
Released for work by issue of PTW/SFT
- State common High voltage levels for RN/RFA platforms
3300V 3.3kV - AOR
4160V - T45
6600V 6.6kV - LPD/LSDA/AO
11,000V 11kV - QE
- Define high voltage
Greater than 1,000V ac or 1,500V DC Between 2 circuit conductors
Greater than 600V ac or 900V dc phase conductor to earth
- What are the numbers of the RN/RFA Books of Reference for High Voltage
BR2000(52)(1) - Operating Guidance for High Voltage Systems
BR2000(52)(2) - Guidance on HV Maintenance and Testing
- Define Permit to Work
A form of DECLARATION , SIGNED and GIVEN BY APC to a PERSON IN CHARGE of work to be carried out any earthed High Voltage apparatus, for the purpose of MAKING KNOWN to such person exactly what apparatus is dead, isolated from all live conductors, has been discharged and earthed and on which it is safe to work.
A PTW contains detail of WHAT WORK IS TO BE CARRIED OUT.
An APC CANNOT ISSUE A PTW to HIMSELF
- Define Switching Schedule
Is a FORM OF CONSENT RAISED AND ISSUED BY AN APC and CHECKED BY ANOTHER AP which shows the ORDER OF ACTIONS required to be completed to achieve the isolation an earthing necessary for THE PTW/SFT TO BECOME VALID.
IT SHOULD COVER RESTORATION.
- What Document controls HV SSOW paperwork
Switchboard Register and Electricity at Work Regulations 1989 which came into force 01 APR 1990
- What is regulation 14 of EAWR
When is work on/near live conductors allowable
a. It is UNREASONABLE in all circumstances for it to be DEAD
and
It is REASONABLE in all circumstances for him to be at work on or near it while IT IS LIVE
and
SUITABLE PRECAUTIONS (including where necessary the provision of suitable protective equipment) are taken to prevent injury
- What is the minimum IP rating for HV equipment in MMS
IP 56
5 - Limited ingress of dust
6 - Protected against strong jets of water
- What is the expansion rate of copper when it vaporises
Up to 67,000 times
- d. How many copies of an LOA
2
PIC
SR
- a. How many copies of Switching Schedule
2
APC
SR
- b. How many copies of SFT
3
PIC
SR
PTW Card Safe
- What are the main components of HV Protection System
Fuses Transformers (voltage & current) Relays Circuit Breakers UPS System
- What is the role of an HV protection system
Detects a fault at lowest possible level of current
Disconnect the faulty plant in shortest time to minimise damage
Discriminate to disconnect only the affected equipment and leave as much healthy equipment as possible
- c. How many copies of SFT
3
PIC
SR
PTW Card Safe
- c. How many copies of IC
3
PIC
SR
PTW Card Safe
- Define HV Live
Used to inform personnel that the ship is either generating or is capable of generating HV or is connected to an external HV supply
- Define HV Dead
Used to inform personnel that the ship is no longer capable of generating HV and all sources of HV supply are disconnected & isolated with CME’s applied
- Define HV Safe
Used to inform personnel that a particular compartment/area is safe to enter with all forms of HV power source disconnected and the appropriate Decay Time has elapsed
- Define CME
Circuit Main Earth - an earth which is positively applied and locked secure in position before a PTW or SFT is issued
- Define Additional Earth
An earth connection applied to electrical apparatus after a CME has been applied and is recorded on the PTW/SFT
- Define a temporary or comfort earth
An earth connection applied to electrical apparatus after a CME by the PiC and not formally recorded in the PTW/SFT
- Why is it not safe to touch HV equipment the moment it is disconnected
Disconnected does not include security ot the disconnection and earthing of the apparatus. The equipment is not safe to touch until it is properly ISOLATED and EARTHED and proved dead to allow a PTW to be issued.
- What must be done to make HV equipment safe to work on
Golden Rules
Disconnect
Isolate
Earth
Cordon
Permit
- What must be done to make HV equipment safe to work on
Golden Rules
Disconnect
Isolate
Earth
Cordon
Permit
- Who on board has overall responsibility for the HV SSOW
Authorising Engineer (AE)
- Who on board should issue a SS/PTW/LOA/IC and SFT
Authorised Person in Charge (APC)
- What steps should the PiC take if he has to leave the point of work
Confirm that all persons, tools and instruments under his control have been accounted for and removed.
Warn persons under his control that it is no longer safe to work on the equipment.
Return any keys to APC
Sign Part 3 of SFT/PTW
- Who exceptionally can issue an LOA in the absence of the APC
RN - Duty ME Senior Rate
RFA - Duty ME/SE Officer if they are at least CP and authorised to issue LOA
- Who can countersign a Switching Schedule
Another Authorised Person
- What date did the EAWR 1989 come into force
01 April 1990
- What are the differences between a PTW & SFT
SFT can only be issued to an AP
SFT allows for specified earths to be removed
SFT allows for the system to be electrically charged
- What is the procedure for using a Potential Indicator
Draw PI and PU and check both have same serial number and are in date for calibration.
Connect earth lead to PI and confirm that display initiates.
Connect earth lead to good earth point to be used when proving dead.
Check PU operates by briefly pressing button
Holding PI by the handle and PU earth stud on another earth - connect PI tip to PU test point
Press PU button and confirm PI displays correct voltage
Without disturbing the PI earth connection test the HV apparatus and confirm by the PI display that the voltage is zero
Without disturbing the PI earth connection - replace the PU stud on earth and re-test the PI by connection to the PU and pressing the button.
- List the contributory factors of the severity of an electric shock
Body Resistance Type of voltage (AC or DC) Level of voltage Frequency of voltage Time
- What are the safe working distance zone names and the distance for 6.6kV
Live Working Zone - 120mm
Vicinity Zone - 1120mm
- What colour are BUSBAR /INCOMER/INTERCONNECTOR and FEEDER Shutters
BUSBAR - Red
INCOMER - RED
INTERCONNECTOR - RED
FEEDER - YELLOW
- What colour padlock do you lock BUSBAR /INCOMER/INTERCONNECTOR and FEEDER Shutters and CME’s with
BUSBAR - Red INCOMER - RED INTERCONNECTOR - RED FEEDER - YELLOW CME - Green
- What warning or caution signs do you fit to what padlocks
WARNING to red padlocks
CAUTION to yellow padlocks
CAUTION to green padlocks
- How do you recognise an HV compartment
Compartment access is to be DISTINCTIVELY marked and display an HV warning sign
- How may non-CP or AP’s gain access to an HV compartment
With an AP/CP escort or on receipt of a LOA
- What items should an HV compartment contain
Correct rubber matting HV Rescue hook First aid/CPR notice and first aid kit Communications (2 systems) to MCR/SCC IP rating tallies on equipment Decay time tallies on equipment
- What are the rules regarding HV keys
All keys to be unique between vessels Keys to be uniquely identified with engraved tallies No keys shall be removed from the vessel Duplicate keys are to be destroyed Keys are to be mustered every 3 months
- What are the rules regarding duplicate HV keys
Duplicate keys are to be destroyed.
In RFA’s duplicate compartment keys may be retained if they are held and mustered by AE
- What are the dimensions of a 6.6kV Additional Earth
3 x phase leads not less than 70mm Sq copper (or equivalent (120mm sq aluminium))
Associated earth clamp having cross sectional area of not less than 35mm sq
- a. Who must apply and remove a CME
APC
- b. Who must apply and remove an Additional Earth
APC
- c. Who must apply and remove a Comfort or Temporary Earth
PiC
- Where is the application of a temporary earth formally recorded
Additional control measures on new PTW form??
- What information about the application of a CME or additional earth should be recorded
Time of application
Specific, detailed location of earth
CME lock number
- on which document should the detail of the application of a CME or additional earth be recorded
Switching Schedule
- What is the minimum insulation resistance reading on the RN/RFA Platforms
AOR (3.3kV) = 4.3MOhm
T45 (4.16KV) = 5.16MOhm
AO/LPD/LSDA (6.6KV) = 7.6MOhm
QE (11vV) = 12MOhm
