Q.1 Define the simple electrical hazards properly
Electrical hazards are part of electricity. This is used in every walk of life even, though it can not be seen, tasted, or smelled only it can feel. Basically, there are two sorts of electricity: static and dynamic. Dynamic electricity is characterized by the flow of electrons through a conductor. To understand this phenomenon, you’ve got must knowledge about elements and atoms. Which has been discussed below :
Elements are the most basic materials. The substance is solids, liquid and gases which are composed of elements. An atom is that the smallest particles of a component that retains all the properties of the element. Each element has its own kind of atom. However, all atoms have inner parts, the nucleus composed of tiny particles called protons and neutrons. The outer part composed of alittle particle called electrons which orbit around the nucleus.
Neutrons have no electrical charge, but protons are charged . Electrons have a negative charge. The atoms of each element have a definite number of electrons, and they have the.same number of protons. The opposite charge electrons and positive charge protons attract each other and tend to hold electrons in orbit.
Electrons are easily moved out of their orbits. This ability of electrons to maneuver or flow is that the basis of dynamic electricity . When electrons leave their orbits, they’re mentioned as free electrons.
Yet, electricity remains a really dangerous hazard for people functioning on or near it. Hazards can include poor work conditions, equipment, or practices. It’s going also to include careless, inadvertent action made on a part of individuals. Many electrical circuits do, they directly pose a heavy shock or burn hazards by themselves.
However, many of this circuit is found an adjacent to circuits with potentially lethal levels of energy. Every minor shock can cause a worker to rebound into a lethal circuit or cause a worker to drop tools into the circuit. Involuntary reaction to a shock may additionally lead to bruises, bone fracture, and even death from collision or falls
Q.2 What can electrical hazards cause
Hazards associated with electricity that cause injury and even death, while working on or near electrical equipment and systems, they are:
Arc – flash burns from contact and flash
Arc- blast impact from expanding air and vaporized materials
Electric shock occurs when the human body becomes part of the path through which electrons can flow. The resulting effect on the body are often either direct or indirect.
Direct electrical hazards:
Injury or death can occur whenever current flows through the physical body . The current of less than 30mA can result in death.
Indirect electrical hazards:
The effect of electric current on the human body depend on:
Circuit characteristics ( current, resistance, frequency and voltage )
Contact and internal resistance of the body.
The currents’ pathway through the body, determined by contact location and internal body chemistry.
Duration of contract
Environment conditions affecting the body’s contact resistance.
Important to understand the contact resistance of the skin. The skin’s resistance can change as a function of the moisture present in its external and internal layers, with the change thanks to ambient temperature, humidity, fright, anxiety etc.
Body tissue, vital organs, blood vessels and nerve tissue in the human body contain water and electrolytes and are highly conductive with limited resistance to alternating electric current. As the resistance of the skin is broken down by the electric current, resistance drops and current levels increase.
# Someone having a sweat-soaked cloth, gloves on both hands. It makes negative skin resistance, leaving only the internal body resistance to oppose the current flow. A circuit in the range of 50volts could be dangerous in the instance. Produce standards consider 4 to 6 mA to be the safe upper limit for children and adults. [ Ground fault circuit interrupter (GFCIs) does not protect against a line-to-line or line to neutral shock. ]
Arc Flash is the light and heat produced from an electric arc that provides sufficient electrical energy for a considerable amount of damage, fire, loss or injury. The electric arc experiences negative incremental resistance, which decreases the electrical resistance as the pressure-temperature increases.
As a result, when the pressure develops and the resistance drops further with heat, some part of the system melts, trips or evaporates until the circuit breaks and the arc is given enough distance to extinguish. Electric arcs produce very bright light when well-controlled and fed by limited energy and are used in arc lamps for welding, plasma cutting and other industrial equipment. The arc can be flash, burn, the heat of the fire. The primary electrical hazard associated with an arc-flash are:
- Radiant heat
Burning results can occur when a person touches electrical wiring or equipment that is used improperly for maintenance. These burns usually fall on the hands. In recent years, awareness about the Arc Hazard has been growing.
Recent studies of reported electrical injuries have indicated that about 80% of documented injuries occur where burns are caused by the release of illuminated fuels from electrical arcs. Electric burns are considered extremely dangerous for a variety of reasons. An important reason is that contact with the circuit does not have to be deadly or even deadly.
When the failure of faulty electrical communication allows the development of an orc flash, a highly conductive plasma fireball may develop. Serious burns can occur more than 10 feet from the source of a flash. In addition to burning from the flask, flammable clothing can burn. Failure to remove adequate clothing quickly can cause severe burns to most parts of the body.
Arc blast occur from high amperage current arcing through the air. This abnormal current flow is initiated by contact between two energize points. This contact can be caused by persons who have an accident while working on energized components. Temperature as high as 35000°F have been recorded in arc-blast research. The primary electrical hazards associated with an arc-blast are:
- Thermal Radiation
- Pressure wave
Q.3 How can electrical hazards be controlled
- Control electrical hazards require that as many reasonable precautions are taken as possible to provide a safe work environment. This starts at the design of the facility and the electric system. It includes the design and specification of the electrical components and equipment, through the installation, start-up operations, and equipment maintenance.
- There are many methods of protecting personnel from arc flash electrical hazards. This can include personnel wearing arc flash personal protective equipment (PPE) or modifying the design and configuration of electrical equipment. The best way to remove the hazards of an arc flash is to de-energize electrical equipment when interacting with it, however, de-energize electrical equipment is in and of itself an arc flash hazard. In case one of the newest solutions is to allow the operator to stand far back from the electrical equipment by operating equipment remotely, this is called remote racking.
- Electrical workers are frequently required to work on or near energized electrical equipment. Safety standards and procedures are being developed that recognizes the fact that arc causes serious injuries at a significant distance from the energizing source. Spectators should stay away from electrical equipment. Although they think they are far enough away, they generally do not have an understanding of what is a safe approach distance which can be referred to in the safety manuals.
Q.4 Which regulations cover electrical hazards
Planning work procedures
All electrical work should be planned before the work begins. For none hazards electrical works, the plan is typically unwritten. All plans must consider all hazards and guards against them. Jobs that are done repeatedly should have a written procedure, which is followed each time the work is performed. If at any time plan is not work, all work must stop and the plan reviewed.
It typically comes in two varieties: plans written specifically for particular jobs.
Written produces should be prepared by a person who understands the work to be done and the electrical hazards involved. Procedures for work performed should be reviewed with the appropriate individuals responsible.
Written procedures must include a step by step outline of the work to be performed and a one-line diagram or another appropriate drawing to be used to discuss the job.
When planning electrically hazardous tasks, the following documentation may be required
- Hazard analysis: this will include a review of the available hazards including a flash hazard analysis.
- Approach distance to exposed energized electrical conductors and circuit devices.
- Requirements checklist for electrical hazardous tasks: This should be a checklist developed by the proper authorities, which outlines the protective requirements for review and approval etc. For various work tasks, voltage levels and approach boundaries etc.