As we discussed in the previous electrical safety blog, electricity is a potential hazard of any redecorating project. Since electricity involves the flow of current through conductive materials, understanding the properties of various materials in your home, and learning how to predict and control the path of electric current, is the key to electrical safety.
Conductive materials commonly found in the home include metal, water with minerals dissolved in it (and most un-distilled water does), people, sweat, and air charged with static. Non-conductive materials include rubber, plastic, wood, glass, and mica.
Most electronic circuits – including those running through the walls and those found within the casings of tools, are made of metal. Many other parts of those tools, however, and other objects such as clothing and containers, are also made of metal, and are not intended to conduct electricity. Electrical accidents can occur when handling a metal tool that has inadvertently come in contact with a circuit, or when moisture from sweat or damp conditions conducts electricity in unintended ways.
Electricity can also cause fires through the generation of heat, which happens whenever the current encounters resistance. Every substance offers some resistance to electrical current, but some much more than others (the classification of materials into conductive and insulative materials can be thought of as a measure of resistance: conductive materials are low resistance, while insulative materials are high resistance). While using insulative materials to block current is the way to protect against electrocution, it can also create a fire hazard. If electrical current can find no path of low resistance, it will take the best possible route, and generate heat to account for the difference between the amount of energy in the current and the amount of energy that can be conducted by the path. Electrical machines channel this heat to accomplish work; their operating devices provide resistance in carefully calculated amounts. But when a current encounters too much resistance, or the resistance is unintended and therefore not productively channeled, the current may arc through the air, seeking a parallel conductor, and generate a good deal of heat in the process, or it may simply heat up the substance to the point that a fire is ignited from the combination of that heat and any combustibles in the area. Attaching a device to a power source that is too strong for its circuitry to handle is a classic way to start electrical fires. The amount of current that a given wire or device can handle should be clearly labeled, as should the source of electricity that you are using.
Prior to use of any electrical tool, it is important to inspect it for potential flaws and hazards in the electrical system. Any potential interruption to or exposure of the machine’s live circuitry is a hazard, and under no circumstances should that tool be connected to a power source. Warning signs of electrical hazards include frayed or damaged cords, open or non-insulated wiring, signs of physical damage on power tools, improper or missing grounds, temporary power connections encased in mud or unprotected, and mismatch between device and power source (a common mistake is to use standard lighting fixtures paired with unusual power sources intended for power tools, or in other hazardous situations)
Precautions to take for electrical hazards include:
– always using double-insulated tools or a grounding cord complete with GFCI (ground fault circuit interruptor) to guarantee that there is adequate protection between yourself and the current and that there is a more attractive alternative path for escaping current to take than through your body
– wear insulating gloves and shoes at all times when working around electricity. This covering will insulate your body from the ground, discouraging electrical current.
– inspect electrical tools regularly
– always check the amperes of devices and power sources, and ensure that they match before using them together.
– always keep insulating materials on hand (scraps of dry cloth, insulating gloves, rubber mats, etc)
– don’t wear metal objects when working with electricity
– don’t touch water, damp surfaces, ungrounded metal, or any bare wires if you are not protected
– do not fasten wires with metal hooks, staples, or any other method that could damage the insulation
– keep electrical cords and equipment clean and free of kinks