Electrical Flashcards
Electrical deaths per year (civilian & fire)
700 civilian
25 fire
of electrical calls per year
3000
Amps
Current flow
Volts
Pressure behind current flow
Kilovolts
1000 volts
Ohms
Resistance to electrical current
Ohms law
Watts = amps x volts
Amps = watts / volts
Volts = watts / amps
Watts
Amount of current times voltage
Voltage ratings
Extremely high voltage = > 60,000
High voltage = 600 - 59,900
Low voltage = < 600
Electricity compared to fire hydraulics
Conductor = Hose
Current = Water
Voltage = Pressure
Amperes = Gallon per minute
Ohms = Friction
Generation plant volt generation
4000 - 20,000
General transmission line voltage
69 kv - 1,000kv
LA Transmission line voltage
230kv
Insulator length ranges
3 - 20ft
of LADWP receiving stations
21
Receiving station voltage
Received = 138kv - 500kv
Stepped down to 34.5kv
Distribution station voltage
Received at 34.5kv and stepped down to 4.8kv
Primary lines voltage
4.8kv
Overhead transformer voltage
Received = 4.8kv
Stepped down to 120 - 240 volts
Conductor
Materials that allow electrical current to flow easily (metals and human beings)
Insulator
Prevent the flow of electricity (glass or porcelain)
How to determine high voltage
1) signs
2) size and shape of insulators
3) distance between conductors
Types of electrical injuries
1) electrocution
2) electrical shock
3) burns
4) falls
Amount of amps that can paralyze or freeze muscles
10 milliamps
Most significant factor in resuscitation of electrical shock victims
Early defibrillation (for every min defibrillation is delayed, survival chances drop 10%
Danger from electrical shock depends on
1) Amount of current
2) duration of shock
3) path of shock through body
Voltage gradient
Decreasing current when energized wire is in contact with ground (ripples)
Touch potential
Contacting live or energized source
Step potential
When victims create a circuit with their feet as they walk across voltage gradient
Arial odder opperation
For high voltage (> 600 volts) operate min of 10 feet away
Communication line voltages
50 volts
30/33/100 rule
1) 30 % fog patters
2) 33 feet away
3) 100psi
When to have victims exit a charged vehicle
only when life threatening emergency exists
When do direct hose stream at high voltage lines
NEVER
