Electricity: Definitions & Information
A term used to refer to the general phenomenon resulting from the presence and flow of electric charge. This includes many physical phenomena like lightning, electric fields, electric currents, and can be put to use in electronic applications and devices.
This is the flow of electric charge, measured by the ampere. An ampere is equal to one coulomb of charge per second.
According to physics, the space around an electrical charge has an electric field property to it.
This can exert force on other charged objects. A moving charge can create a magnetic field, which is not a completely different thing to an electric field.
Power is measured in Watts, and is electric current flowing in a circuit with resistance. Devices converts this into useful forms, such as heat, light, motion and sound.
The term power may often be used to refer to the amount of power used in a certain amount of time, in which case the term watt-hour is used.
This can refer to the energy stored in an electrical field, the energy supplied by electricity, or the potential energy of a charged particle in a field of electricity.
The electrical energy unit is the joule – although many electrical companies use the watt-hour (Wh) or the kilowatt-hour. Electrical energy is basically the amount of ‘work’ that can be done by electricity.
Electric shock and injuries
Shock can occur when a human body comes into contact with a voltage source high enough to cause sufficient flow of current through muscles and nerves. The minimum detectable source is about 1 milliampere (mA).
If sufficiently high, a current can cause tissue damage or heart failure (fibrillation). ‘Electrocution’ refers to a fatal electric shock. Less severe electrical shocks can cause tingling sensations, or burns.
The amount of current passing through a body can vary based on the nature of contact, the current path, the condition of the body part and the voltage of the source. The effect can also be different from person to person.
Due to these varying factors, any source providing over 50 volts should be considered a possible danger – and 110 volts can potentially be lethal.
Electric arcs can occur with any voltage, and can cause UV damage to unprotected eyes and skin, along with severe thermal burns.
Overloaded power cables and electric sources area also a frequent source of fire. A source as small as an AA battery when stored with metal coins can lead to a short circuit and inflict burns.
Appliances should be properly earthed, therefore vastly reducing the possiblity of electric shock. In properly set up systems, a fuse should blow or circuit breaker should flip when live current touches a dangerous part of the equipment – this called a short circuit.
It can cause noise and smoke, but is far safer than the risk of electric show, and certainly makes the problem obvious to those in the area. A short circuit will also result in loss of power in the affected area.
Due to the particular conductive properties of metal, many plumbing systems now use plastic piping to serve bathrooms and kitchens. This does not guarantee electrical safety however. The presence of water increases the risk, although pure water isn’t in face a very good conductor of electricity on it’s own.
Most water supplies however are not pure, and the content of the water often provides excellent conductive properties in the form of dissolved particles (salts, etc) with break down into charged ions.
For this reason, mains electrical sockets are prohibited in the UK and most bathroom and kitchen appliances are constructed or coated in plastic, as plastic will not conduct electricity. UK laws also require that Residual Current Devices (R.C.D.s) are installed, and this has reduced the level of risk again.
People should not be working on live conductors. If this has to be done, insulated gloves and tools need to be used.
If both hands make contact with surfaces or objects at different voltages, the charge can pass from one hand through to the other, and therefore through the heart causing damage or death.
This can also happen if a high enough current passes from one hand to the feet. Qualified and trained professionals should be employed to carry out electrical work in all circumstances.
Electric Shock First Aid
Shocks can be categorised based on the area of the body the current passes through. A macroshock involves the current passing across unbroken skin and through the body.
This could be from the thigh down to the foot or from the hand to the leg (involving the current passing through the heart and potentially causing much more damage). A microshock involves current flowing directly towards the heart tissue.
Before helping a victim of electric shock, you must first ensure the surrounding area is safe, by disconnecting the source of power. Only do this if it safe enough however – if plugs or power sources are not insulated properly, badly constructed, or broken, you need to look for another way to shut down the power.
Likewise, if the area is covered with water, or another electrically conducting material, you will not be able to get close. If you can touch the person with a non-conductive object such as a wooden broom, this can be used to drag them away from danger – or move an electrically charged object they may be in contact with (such as a hairdryer or toaster).
Whether you have made contact with the injured person or not, you need to call emergency services for an ambulance.
You need to tell them about the nature of the environment, as they may find it neccessary to involve the fire-brigade, or some other organisation capable of disconnecting electricity to your area.
If you are sure the surrounding area is safe, and you know there is no current passing through the victim, you may touch them in order to check for breathing and pulse.
If none are present, begin resuscitation. If breathing and pulse are steady, you can attend to any electrical burns by applying dressings that will not stick. Never use ointments or oils.
Talk calmly and reassuringly to the victim until the ambulance arrives.
The International Electrotechnical Commission (along with the IEE, IEEE, VDA, etc) define high voltage as voltage with more than 1000V for alternating current and 1500V for direct current.
Mains voltages are indeed capable of serious harm and fatality, however they are rarely classified as high voltage risks as they are encase and insulated forms of electricity, and therefore protected for the most part.
In homes, buildings and business offices however, all electrics need to be certified and tested by professionals, and new-build houses have to have their electrics checked by those with sufficient training and certification.
A defibrillator uses a high voltage of 6 Amperes in order to cause ventricular contraction followed by normal heartbeat.
These initials stand for the Institute of Electrical Engineers, a professional organisation founded in 1871 for British electronics and electrical workers and companies. Now merged with the IIE, it formed the Institute of Engineering & Technology.
The IET represents the electrical and technological engineering community in matters concerning the public and goverment, assisting the goverment with public awareness Further to this, the IET provides regulations, as well as accreditations to qualifications through the UK, and hosts information factsheets on their website for the public’s use.
The IET also has a presence in Australia.