Showing posts with label Safety. Show all posts
Showing posts with label Safety. Show all posts

Sunday, 3 March 2019

Electrical Rescue Techniques

Electric shock accidents are caused by an electric current passing through the body. The effects from a shock can be anything from a tingling to instant death. Knowing what to do in the event of an electrical shock could save a life.

Approaching the accident:

Take a moment to assess the scene and look for any obvious dangers.
Check for the source of the electrical shock. 
Look to see if the victim is still in contact with the source. 

Remember that electricity can flow through the victim and into you. 
  • Call emergency number 108/112 as soon as possible.
  • Never use water, even if there is a fire, as water can conduct electricity.
  • Never enter an area where electrical equipment is used if the floor is wet.
  • Use a fire extinguisher made for electrical fires. Fire extinguishers for use on electrical fires will be labelled as a C, BC, or ABC extinguisher.
  • Never rush into an accident situation.
  • Get the aid of trained electrical personnel if possible.
  • Approach the accident scene cautiously. 


Examining the scene:

Visually examine victims to determine if they are in contact with energized conductors.

Metal surfaces, objects near the victim or the earth itself may be energized.
You may become a victim if you touch an energized victim or conductive surface.

Do not touch the victim or conductive surfaces while they are energized.

De-energize electrical circuits if at all possible. 

Methods to de-energize:

An extension or power cord probably powers portable electrical equipment.
Unplug portable electrical equipment to remove power.
Open a disconnecting device or circuit breaker to de-energize fixed electrical equipment. 

Hazards and solutions:

Be alert for hazards such as stored energy, heated surfaces and fire.
If you can’t de-energize the power source use extreme care:
Ensure that your hands and feet are dry.
Wear protective equipment such as low voltage gloves and overshoes if available.
Stand on a clean dry surface.
Use non-conductive material to remove a victim from the conductor. 

High voltage rescue:

Special training is required for rescues if high voltage is present.
Protective equipment such as high voltage gloves and overshoes must be worn.
Special insulated tools should be used 

Insulated tools:

Insulated tools, with high voltage ratings, are a lifesaver!
Use devices such as hot sticks or shotgun sticks to remove a victim from energized conductors.
In some cases, non-conductive rope or cord may be used to remove a victim from a conductor. High voltage rescue:

Rescuing the victim:

Stand on a dry rubber blanket or other insulating material if possible.
Do not touch the victim or conductive material near the victim until the power is off. 
Once power is off, examine the victim to determine if they should be moved.
Give “First Aid.” 

First Aid:

A victim may require Cardio-Pulmonary Resuscitation (CPR).
If the victim is breathing and has a heartbeat, give first aid for injuries and treat for shock.
Ensure the victim gets medical care as soon as possible.
Provide medical personnel with information on voltage level, shock duration & entry/exit points.  The treating/attending physician must have detailed specific information to properly diagnose and care for the victim.  
The physician must determine whether the victim should be sent to a “Trauma or Burn Center.” 




Basics about Electrical Shock

Basically, electrical hazards can be categorized into three types. The first and most commonly recognized hazard is electrical shock. The second type of hazard is electrical burns and the third is the effects of blasts which include pressure impact, flying particles from vaporized conductors and first breath
considerations.

Electric shock occurs when the body becomes part of an electrical circuit. Shocks can happen in three ways.

• A person may come in contact with both conductors in a circuit.
• A person may provide a path between an ungrounded conductor and the ground.
• A person may provide a path between the ground and a conducting material that is in contact with an ungrounded conductor.

The terms high voltage and low voltage are relative terms. In transmission-line terminology, "low voltage" is much higher than the 600 volts. At home, you would not think of 600 volts as being low voltage.

Even when applied to 120-volt circuits, the term low voltage is deceiving. To some people low voltage means low hazard. Actually, low voltage does not necessarily mean low hazard, because potential difference is only one factor making up the dangerous effects of electricity. For purposes of this Lesson,you can think of "low voltage" as being a potential difference of 24-600 volts. 

The extent of injury accompanying electric shock depends on three factors.
• The amount of current conducted through the body.
• The path of the current through the body.
• The length of time a person is subjected to the current.

The amount of the current depends on the potential difference and the resistance. The effects of low current on the human body range from a temporary mild tingling sensation to death. An electric shock can injure you in either or both of the following.

• A severe shock can stop the heart or the breathing muscles, or both.
• The heating effects of the current can cause severe burns, especially at points where the electricity enters and leaves the body.

Other effects include severe bleeding, breathing difficulty, and ventricular fibrillation. In addition, you may strike something, or have some other accident as a result of your response to the shock. The effects of electric current are listed in below. 

The extent of injury accompanying electric shock depends on three factors.
• The amount of current conducted through the body.
• The path of the current through the body.
• The length of time a person is subjected to the current.

The amount of the current depends on the potential difference and the resistance. The effects of low current on the human body range from a temporary mild tingling sensation to death. An electric shock can injure you in either or both of the following.

• A severe shock can stop the heart or the breathing muscles, or both.
• The heating effects of the current can cause severe burns, especially at points where the electricity enters and leaves the body.

Other effects include severe bleeding, breathing difficulty, and ventricular fibrillation. In addition, you may strike something, or have some other accident as a result of your response to the shock. 

Current is the killing factor in electrical shock.  Voltage is important only in that it determines how much current will flow through a given body resistance.  The current necessary to operate a 10 watt light bulb is eight to ten times more current than the amount that would kill a person.  A pressure of 120 volts is enough to cause a current to flow which is many times greater than that necessary to kill. 

The following values are given for human resistance to electrical current in Figure 1: 
Figure 1: Resistance Values
With 120 volts and a skin resistance plus internal resistance totaling 1200 Ohms, we would have 1/10 ampere electric current, that is 100 milli amperes.  If skin contact in the circuit is maintained while the current flows through the skin, the skin resistance gradually decreases.  During this time, proper first aid
can mean the difference between life and death. Sufficient circulation can sometimes be maintained by heart compression, which should always be supported with mouth-to-mouth resuscitation.  This combination of treatments is commonly known as CPR.