CFD Electrical Safety

Question 1

Voltage

Answer 1

Difference in electrical potential between two point in a circuit

Force that causes the flow of electricity and is measured in volts

Compared to water pressure

Question 2

Current

Answer 2

Flow of electrical charge

Compared to the rate of flow of water in a pipe

Question 3

Resistance

Answer 3

Similar to the effect of friction on the flow of water in a pipe

Question 4

Insulators

Answer 4

very high resistance materials

Ex. Porcelain, glass and plastic

Question 5

Conductors

Answer 5

the low resistance materials

Ex. Metals

Question 6

Grounding

Answer 6

process of mechanically connecting isolated wires and equipment to the earth

Question 7

Two conditions that cause the majority of electrical fires

Answer 7

arcing and overheating

Question 8

arcing

Answer 8

sudden flash of electricity between two points of contact

Question 9

overheating

Answer 9

overloading of electrical conductors and motors

Question 10

safe limits approach

Answer 10

until the local electrical utility verifies the voltage, emergency responders must maintain a safe clearance distance of 7m

Question 11

electricity takes all paths to the ground

Answer 11

more current will flow through the path of least resistance

Question 12

step potential

Answer 12

Refers to the risk of electrocution based on the possible voltage running through the ground

If you were to place one foot near the point of ground contact and your other foot a step away, the difference in voltage would cause electricity to flow up one leg, through the abdomen and back down the other leg

Question 13

Touch potential

Answer 13

Similar to step potential, electricity would flow through your body if you were to place your hand on an energized source while your feet we at some distance from the source

Question 14

Effects of electricity on the body

Answer 14

Dependent on the amount of current and the length of time the body is exposed to it

The path of electricity through the body is also critical

Question 15

Medical follow up

Answer 15

Effect can be delayed up to 24 hours

Even a short exposure to electricity can cause an irregular heart rhythm resulting in death within hours

Question 16

Fallen or low hanging wires

Answer 16

A distance of at least 10m or more is recommended from the down wire or conductive object it is in contact with

Question 17

Getting out of a vehicle

Answer 17

Contacting the car and ground at the same time can be Fatal

Shuffle step or hop (keep feet together)

Question 18

Using water on electrical fires

Answer 18

There should be a minimum of 700kpa at the nozzle

The fog spray should be set to 30 degrees fog pattern

FF must be at least 10m aware from energized source

Solid bore, straight stream and foam should all be avoided

Further electrical resistance of the ground can change due to water run-off

Question 19

Overhead power lines near buildings

Answer 19

Initial minimum 7m from working zone

Question 20

Radiofrequency (RF) Radiation

Answer 20

Two areas of the body, the eyes and the testes, are particularly vulnerable to RF heating because of the relative lack of available blood flow to dissipate the excessive heat load