Electrical Safety Handbook Flashcards
Electrical Safety Handbook
Whaer is Voltage?
The difference in electrical potential between two points in a circuit
Electrical Safety Handbook
What is Current
A flow of electrical charge
Electrical Safety Handbook
What is Resistance?
its similar to the effect of friction on the flow water in a pipe.
HIgh resistance=insulator
Low resistance=conductor
Resistance is measured in Ohms
Electrical Safety Handbook
What is grounding
Is the process of mechanically connecting isolated wires and equipment ot the earth, with sufficient capacity to carry any fault curren and to ensure the wires and equipment remain at the same potential (same voltage) as the earth
Electrical Safety Handbook
What causes electrical equipment to become faulty?
- worn out or deteriorated
- improperly installed
- improperly maintained
- improperly used
- dameged or broken
- adverse weather/natural events exposure
Electrical Safety Handbook
What is arcing and how hot does it get?
an electrical arc is a sudden flash of elevtricity between two points of contact. and arc is extremely hot. 20,000C, 35000F
Electrical Safety Handbook
What are the safe limits of approach for live lines?
- 750-150000 volts is 3M or 10ft
- 150001-250000 volts is 4.5M or 15ft
- 250001 and higher is 6M or 20ft
Electrical Safety Handbook
How far can a conductor Swing or sag when heated
1.8m
Electrical Safety Handbook
What are the two problems that potential gradient or voltage differance create?
Step Potential and touch potential
Electrical Safety Handbook
The effect of electricity on the body and the severity of the shock depends on what?
- COndition of the skin
- Area of skin exposed to the electrical source
- Pressure of the body against the source
- moisture level of the surface of the skin
Electrical Safety Handbook
Any vivtim of electrical shock should be assessed for the following effects on the body
- Contraction of chest muscles, cuasing breathing difficulty and unconciousness
- respirator distress caused by temporary paralysis of the respirator center
- rapid irregular heart beat (ventricular fibrilation) mainly resulting from contact with low boltages
- burns to tissue at the entrance and exit points
- fractures cause by muscle spasm
- injuries such as fractures, contusions, internal bleeding due to calls
Electrical Safety Handbook
Does standard response protective clothing provide protection from electrical hazards
NO
it will provied electrical arc flash protection
Electrical Safety Handbook
How far away should you use the shuffle step form an energized vehicle
10M or 33ft
Electrical Safety Handbook
What are the three parts to a typical electrical system
- generation
- transmission
- distribution
Electrical Safety Handbook
What does GFCI stand for
ground fault circuit interrupters
Electrical Safety Handbook
What steps are outlined when responding to downed wires
- Before getting out of your vehicle, examine the surroundings carefully and make sure you are parked well away form fallen wires.
- Stand well back, at least 10M or more away. Look for and locate all wires ends
- Establish the safe zone, at least 10M away from wires and aything the wires bay be touching
- Secure the area
- Do not attempt to more any fallen wires, call and wait for elevtrical utility personnel.
Electrical Safety Handbook
What are the safe distances for using water on live electrical equipment?
use a 700 Kpa nozzle
1. 0-750 volts 1.5M 5ft
2. 751-15000 volts 4M 13ft
3. 15001-500000 volts 7M 23ft
Electrical Safety Handbook
What should not use on a electrical fire?
- strait water stream
- foam
Electrical Safety Handbook
What is the standard precautionary approach to fiight fires on power line equipment?
- wear full trunout gear and SCBA
- position the apparatus upwind and out fo the line of fire of the vehicles tires
- evaculate people located in path of smoke plume and at safe distances from a ground gradient grid or tire explosion
Electrical Safety Handbook
High voltage power line are insulated by air space. At what distance would flames degrade the insulating quiality of the air to the point of enabling electricity to jump to the surface?
If flames are within 2m or 7ft of the live conductors
Electrical Safety Handbook
What are the arc over hazard zonse based on power line voltage?
Note these are the same as ground step potential hazard zones created by trees touching power lines.
volts
115000 or less 10m(33ft)
up to 230000 15m(50ft)
up to 500000 32m(100ft)
Electrical Safety Handbook
On distribution power lines where are the high voltage primary power lines located and what is their voltage?
They are typically above the transformer and are between 2400 volts and 27600 volts
Electrical Safety Handbook
On distribution lines where are the neutral and secondary power lines (120/240 and 347/600) located?
below the transformer are are weather coated but should not be considered insulated or safe to touch
Electrical Safety Handbook
What are the limits of approach for fires on both wood and metal electrical structures?
Low level flames has a limit of 10m 33ft
high level flames within 2m(7ft) of power lines the limis it 32m(100ft)
Electrical Safety Handbook
Where is the pole number usually found?
1.8m or 6ft above the ground
Electrical Safety Handbook
Response to fire on power line equipment
- assess the situation from at least 10m(33ft) back. attempt to determine the voltage involved. if you arn’t certain assume the highest voltage.
- determin the safe sone, secure the area and keep people back at least 10m(33ft)
- call the local elecreical utility, and inform other emergency responder of the hazards.
- set the nozzle to produce fog(minimum 30degree pattern) and ensure the designed pressure stays at or above 700kpa or 100 psi at the nozzle
- direct the fog at the pruning pole or equipment. stay back at leas 10m (33ft) unless you are certain of the voltage. it is safe to direct a fog steam at high voltabe line providing you maintain the seperation between yourself and the live wires or electrical equpment
Electrical Safety Handbook
Respoonses involving trees or other objects in contactwith a power line.
- assess the situation form the distances shown in the ground step potential hazard table 5 (see table 5 on page31)
- determine what objects are contacting, or are close to power lines
- if objects are in contact with power lines, determine the safe zone and secure the area
- call local electrical utitly and informt hem of the loaction and nature of the object contacting the power line. DO NOT ATTEMPT REMOVAL
- wait for the logal electrical utility personnel to isolate and de-energize the power line.
Electrical Safety Handbook
How deep are under ground cables?
Typically under ground cables are buried at least 1m(3ft) below ground levl
Electrical Safety Handbook
What is a transformer?
dveice used to step-up or step-down voltages
Electrical Safety Handbook
what is used to cool a transformer
insulating oil with is combustible and has a flash point of 145C(295F)
Some transformers contain Polychlorinated biphenyls (PCB)
Electrical Safety Handbook
What is a conservator
lare tank located at the top of a transformerthat allow for expansion and contraciton of the cooliing oil when the transformer is carrying load
Electrical Safety Handbook
What is a bus bar
Metal conduit or pipe that is used within substaions to carry electricicty fro m transforrmers to other devices
Electrical Safety Handbook
What are control cables
cable that is attached to large power transfomrer to carry low bolatace electricity for controlling cooling fans, pumps and motors
Electrical Safety Handbook
Called to a fire in a substaion or swithyard
- Notify dispatch to call the electrical utility immediately, and inform other emeefgency responders of the identified dangers
- upon arrical, park vehicles and aparatus wella way form the substation
- secure the area, keep on-lookers back at least 100m(330ft)
- obtain a copy of the emergency response plan for the substation
- prepare equipment and protect exposures applying ware using fog spary (700kpa 30 degree
- wait for electrical utility personnel to arrive. do not enterr the substaion unescorted.
- with advice form the lectrical utility personnel, fight the fire
Electrical Safety Handbook
what are additional difficultie that may be encountered at privetely owned substations
- identifying or locating the owner
- problems locating the occupants electrician
- property overgrown with shrubs, bushes and trees
- poor housekeeping practices and maintenance of equipment
Electrical Safety Handbook
When do PCBs become hazardous to firefighters?
under certain conditions, PCBs in the presence of oxygen when heated between 250-700C may produce harmful products of compustion such as dioxins and furans.
Electrical Safety Handbook
What agent should be used on PCB fires?
Where safe alternatives to water are available(CO2, dry chemical), they should be used. if non-water alternatives are not an option, the quantities of water should be minimized to the extent possible to limit the spreat of cotamination.
Electrical Safety Handbook
You suspect PCBs in a fire
- Consult the Emergecny Response Guidebook (ERG)
- wear full turnout gear and SCBA
- position apparatu upwind and approach from upwind
- us dry chemical, CO2, or foam if possible
- provide for liquid runoff ontainmen
- evacuate peoople located in path of the smoke plume
- folow standard decontamination procedures
- ensure you aan you rgear are tested afterward for possible exposure
Electrical Safety Handbook
What minimum distance must be maintained betwee arial apparatus and power lines?
3m (10ft) away from power lines
Electrical Safety Handbook
How fare away should you stay away from a service drop in a hous?
at least 1m (3.5ft)
Electrical Safety Handbook
Procedure for turning off main power switches?
- ware dry leather gloces
- use left hand
- trun away from the switch
Electrical Safety Handbook
What are the signs of and electricaly charged wet floor
- sparking
- unconscious victims or person receiving shocks from equipment touching the wet area
Electrical Safety Handbook
Descripe and off-grid photovoltaic system
off grid or stand alone system rely solely on PV panel to produce direct current (DC) electrical energy and contain battery banks to store the energy. a tpical sstem si made up of solar PV panels, combiner boxes, charge controller, disconnect devices and battery banks.
Electrical Safety Handbook
Discribe a grid tied solar system
grid tied sstem generate electriclal power through solar PV panels andany excess electricity is sold back to the grid. a typical system is made up of solar panels, combiner boxes, inverter, disconnect devices and metres.
Electrical Safety Handbook
What are the two types of wind turbines systems?
- A small wind system consists of one or more wind trubines with a rated output up to and including 100kW. Small wind system are typically found on farms and rural residential properties. Small wind turbines may not ahve a disconnecting device. they woul dincorporate shorting plug
- a large wind system consists of one or more wind trubines with a rated output exceeding 100kW. Large wind systems will typically have a number of wind turbine tower arranged into an array or wind ‘farm’.
Electrical Safety Handbook
What is a fuel cell?
a fuel cell is a device that generates aDC electrical current by the electomechanical combination of a continuously supplied gaseous fuel and oxidant.
Electrical Safety Handbook
Signs of tampering with an incoming electrical line(gorw op)?
- taps made underground by coring though foundtion splicing into the utility feed
- cutting inot the untitly feed before the meter if the overh ead mast is concealed in the attic
Electrical Safety Handbook
What are the three types of hazard associated with grow ops?
- electrical
- fire
- entanglement
Electrical Safety Handbook
What are the elevtrical hazards associated with Grow ops?
- even if the meter was removed, the tapped connection are done on the utility feed whcih is live at all time until the utility company disconnect the feed from the steet
- unapproved wiring methods such as unprotected wiring
- exposed wiring, terminals and connections
- equipment not bonded or grounded properly, creating short circuits and hazrds
- metals in close proximity become engergized causing serious injury aor electrocution
- deliberately set booby traps of various types attach to door, handles and windows
Electrical Safety Handbook
Whare the fire hazards associated with Grow ops
- high heat producing equipment placed on or near bulding combustibles
- overloading circuits with inadequate or bypassed over load protection
- use of inersized extension cords
- use of gas producing batteries in an enclosed area (basement
Electrical Safety Handbook
What are the entanglement hazards associated with a grow op?
- Extensive use of extension ords
- improperly installed low hanging flexible ducting
- improperly strun and unprotected wiring
- batterie or capacitors randomly positioned and wired together
