Incidents Involving Electricity (PN 769) Flashcards
What are the 5 Electricity Company Premises listed in the note?
A) Power Stations B) Sub Stations C) Fenced Enclosures D) Distribution Cables/Equipment E) Wind turbines
Where are substations Situated within a building?
Against an external wall and in a room protected by 4 hour rated material
What can be found on every Electricity distributers facility?
A conspicuously placed identifier plate
What might smoke issuing from the pavement indicate?
Fire in Electrical Ducting
What 7 ways of electric shock delivery are listed in the note?
Touch, overload, application of water, conduction by water, residual charge, arcing, damaged equipment
What are the 5 main hazards listed in the note at incidents involving Electricity?
1) Electric Shock
2) Fire
3) Explosion
4) Hazardous Gases (asphyxiants used to protect electrical equipment) and Liquids
5) Trips
What 3 insulating materials are listed in the note?
1) PVC
2) PCBs
3) Sulphur Hexafluoride
Are PCBs solids or fluids and what does PCB stand for?
Polychlorinated Biphenyls and they are fluids which are highly toxic and not biodegradable contained in some transformers (normally labelled)
What does SF6 stand for?
Sulphur Hexafluoride
Is SF6 a powder or a gas?
A gas which is heavier than air but when it ‘breaks down’ in a reaction it may present as a powder that can contaminate
** What is the minimum safe approach distance when using ladders or Aerial Appliances at an incident involving electricity?
10 meters (though this may increase if weather conditions are likely to cause cables to move)
** At an incident involving a Wind Turbine what 2 things should an IC request and get confirmed before offensive firefighting commences?
1) That any power supply to the turbine is isolated
2) That the blades are locked out
What are the 3 ‘fire hazards’ associated with electrical incidents listed in the note?
1) Large quantities of fuel
2) Explosion of oil filled equipment
3) Toxic smoke from insulation
At incidents involving: Overhead Cables Substations Pavement Level Ducting What must the IC request?
National Grid Authorised Person
Can firefighters lift inspection covers to access pavement level ducting?
Not initially and only when the ‘Authorised Person’ has confirmed that the power has been isolated and there is no residual current
What should an IC establish once a live source of electricity has been identified?
An appropriate ‘Restricted Zone’
In establishing a ‘Hazard Zone’ for a Pavement Level Ducting Incident what 3 things should the IC take into account?
1) Other inspection cover that may become involved
2) Debris from Explosion
3) Effect on Adjacent Premises, Glass shop fronts etc
The theft of components such as earthing cables may create what hazard?
The electrification of other surfaces such as Gates and Fences
Can crews ‘Pass’ electricity warning signage?
Not until an ‘Authorised Person’ is on site
When requesting an ‘Authorised Person’ what should the message include?(3)
1) Information gathered from ID signs and plates
2) RVP (where appropriate)
3) Access restrictions
An ‘Authorised Person’ might take how long to attend according to the note?
2 hours
What 3 things should the IC consider prior to isolating the electricity at a premise?
1) Machine Processes
2) Welfare of Occupants
3) Business Continuity
Can entry be made to a premise if the ‘Authorised Person’ is UNABLE to confirm that the power is isolated and/or there is no residual current?
Not if high voltage is present and only with control measures if low voltage
What is classified as ‘High Voltage’?
More than 1000 Volts AC
Or
More than 1500 Volts DC
What does AC stand for?
Alternating Current
What is the minimum safe working distance for a ‘Monitor’ at an incident involving Electricity?
30 Metres
In what circumstances may it be necessary to apply water or foam directly to Apparatus?
Where it is ‘Low Voltage’ and carbon dioxide or dry agents are not available
How is Low Voltage defined?
Less than 1000 Volts AC
Or
Less than 1500 Volts DC
What does DC stand for?
Direct Current
What 2 types of extinguishing media do not damage electrical equipment?
1) Carbon Dioxide
2) Vaporising Liquids
What does UPS stand for?
Uninterruptible Power Supply, UPS’s will have a backup means of supply normally a generator or battery bank which must also be isolated
LFB Electrical gauntlets/gloves must not be used where Voltages are known to exceed how many Volts?
3300
High Voltage overhead power lines can ‘Arc’ in dense smoke, a safe corridor of how many meters is measured out below?
10m’s (on any side adjacent to operations)
What MUST the IC establish when working in the vicinity of live equipment?
Safety Officers
Before using Electrical gloves/gauntlets what must you check?
That they are not damaged or damp/wet
Which toxic gas is contained in smoke from burning PVC?
Hydrogen chloride
Post incident the IC should gather information to support the PRO and PRC. What does PRO and PRC stand for?
Performance Review of Operations (PRO) and Performance Review of Command (PRC)
What must be used ‘En route’ to inform on arrival tactics?
The MDT
Which type of current will make muscles contract AC or DC?
Actually both cause muscles to contract. AC current will cause a series of contractions DC current a continuous contraction
(not in the note)
Electrical Transmission cables mounted on poles can be vertically hung (one above the other) or horizontally hung (one next to the other). Which are high voltage and which are low voltage?
Horizontal - high voltage
Vertical - low voltage
If a person is ‘lying on top of a transformer, switch or anywhere else above ground level’ can they be touched?
No, unless the ‘Authorised Person’ says it’s safe to do so
High Voltage equipment that is not screened is normally a minimum of how many meters above ground?
2.5 meters
Rescues from towers or poles, which have been made safe, can only be carried out by who?
Personnel with the necessary specialist skills (line rescue)
What is the minimum safe approach distance for rescues in the vicinity of overhead lines, substations and other electrical supply equipment?
5 meters
Can battery banks be isolated?
No, only the supply cables to and from them
When using ‘handheld jets’ what is the minimum safe approach distance?
20 metre corridor (never direct the jet at the lines)
If a domestic supply is isolated what must the IC ensure before leaving the scene?
That the supply is marked (tagged) to show that it has been shut down
