Today we're going to discuss an electrifying topic, and learn how to avoid shocking experiences.
Compliance and Safety
When we discuss electricity, there are a number of terms we need to be familiar with current, volts amperes and watts are the most important.
- Current - is the intensity of electricity and is measure in amperes/amps. Most household and industrial electric wiring carries 15 to 20 amps the thick of the wires the more current they can usually hold. It's important to remember that it's amps that deliver electric shocks, and it doesn't take many amps to cause a serious injury. In fact, contact with the amount of electricity that's needed to power just a Christmas tree bulb can be fatal if it passes through your heart.
- Volts - are another term we hear a lot, they measure the force behind the current that's flowing. In North America, most power tools and household appliances run on 120 volts, but some specialize and heavy duty equipment that requires extra power often runs on 220 or more volts, like amps the higher the voltage the greater the danger.
- Watts - are a third term that's frequently encounter when we discuss electricity. Watts can be thought of as the combination of amps and voltage. You can determine how many amps something uses by dividing wattage rating by the voltage in the electrical system it's running on. For instance, if your home is a 120 volt electrical system, a 120 watt light bulb uses 1 amp of power, 120 watts divided by 120 volts. A 60 watt bulb uses only 1/2 an amp, a 1200 watt hairdryer would use 10 amps which explains why the light sometimes go dim when someone turns a hairdryer on.
Now let's take a look how an electrical system works.
Circuits and Flow
Electricity flows when a loop or circuit is completed. This loop is created when an interrupted stream of electricity passes through a piece of equipment and returns to the power source. Only when a circuit is complete where are tools and machinery be powered up and ready to go. To control these circuits, tools and machines have an on off switch; When a switch is on the circuit is completed and electricity will flow, moving the switch to the off position breaks the flow of electricity and stops the equipment from running.
An electrical outlet is a circuit that's waiting to be completed. A single electrical outlet can actually create a number of different circuits, since each tool, light or piece equipment that's plug into the outlet establishes its own loop. When too many pieces of equipment are hook into the same outlet, all trying to draw the current they need that circuit can become overloaded and heat up, this excess heat can damage tools, equipment or even a wiring itself. To help guard against these types of situations, circuit breakers and fuses are built into electrical systems, if they detect too much electricity flowing through the wiring they'll break the circuit, this stops the flow of electricity before problems can develop. Circuit breakers, fuses and wires are all rated by how much electricity they can safely carry, you should never install breakers or fuses with higher ratings than the wires they're connected to. The breakers would allow too much electricity to pass through the wires and increase the risk of a short circuit or fire. If a breaker trips you need to remove some of the equipment from the circuit so that the remaining machinery can operate safely.
One of the most important things about electricity is that if somehow leaks or jumps from the conducting wire it will still try and complete a circuit by finding the shortest path to the ground. Unfortunately, this can lead to a nasty shock if you're in its path. Control grounding is what helps to keep us safe if this occurs. For instance, if electricity leaks through crack or defective wiring a ground wire can direct the electricity back through the electrical circuit to the ground. You can see the ground wire easily in 3 prong plugs; it's the wire that ends in a round prong. But in order for a ground wire to work, the outlet that is plug into must be grounded as well. Just because an outlet can take a 3 prong plug doesn't necessarily mean that it is grounded, the only way to be certain that the outlet is grounded is to test it. In addition to being grounded, nowadays many outlets are fitted with a ground fault circuit interrupter or GFCI, this device can be a lifesaver. It immediately shuts off the flow of electricity when it senses a change in a string of the current in a circuit. For instance, if a crack cord in a tool allows electricity to leak out and reduces the string of the current in the system, the ground faults circuit interrupter will cut off the electricity before it has a chance to hurt you.
Recognizing and Avoiding Hazards
Once you know how electricity works you next need to learn how to recognize and avoid potential hazards. Remember electricity can be dangerous just like the signs say. Electrical hazards most often result in, shocks, burns, fires. So, you need to be on a look out for conditions that can cause these problems. A number of accidents are the result of faulty wiring, so be sure to look at the installation on all power cords for cracks or other defects, don't forget extension cords. Report any problems and have damage cord repair or replace immediately.
Overloaded circuits are another problem, drawing too much current can cause wiring to heat up which increases the risk of a fire. So keep your eye out for outlets with lots of cords plug into them or the excessive use of power strips. Look for other outlets nearby that around separate circuit where you can plug in some of the equipment. Limit the use of extension cords to temporary set ups and be sure to choose a cord that can handle the amount of the electricity you're going to be using. Remember all electrical equipment should be properly grounded, look for adapters being use with all 2 pronged outlets without the ground wire being connected or 3 prong plugs that have been altered to fit into a 2 pronged outlet if you find any, determine what is to be done to remedy the situation.
You also need to exercise caution when selecting electrical equipment. Use double insulated tools whenever possible, they have built in protection against shock, in the event of a problem the special safety shielding inside these tools conducts stray electricity away from you. If you're working with electrically powered machinery, you wanna look out for sparks they often indicate that there are damage connections and that can lead to a serious problem. If you do encounter an electrical problem, don't try to fix it yourself unless you're qualified. Instead, advice your supervisor about the situation and contact a repair person. If you are a qualified worker whose services electrically powered equipment and machines, make sure to disconnect all power sources before making repairs or adjustments. And don't forget to use proper lock-out/tag-out procedures.
If a machine has been locked and tagged by someone else, don't try to restore power before necessary repairs have been made, and the locks and tags have been removed. Never try to overwrite safety devices like electrical interlocks, this keep machine being powered up before it's safe. If you are working around energized lines or machinery remove key chains, metal jewelry and other objects that can conduct electricity, just put them in your pocket isn't enough. Materials that are use around electricity can cause problems too. Excess grease and debris can cause motors to overheat so keep your eyes filled to them. Don't use conductive materials like liquids, steel wool or even metal hand tools near energized parts unless you take the proper precautions.
Flammable materials are another thing that doesn't react well with electricity, so make sure you're aware of any flammable materials in your work areas, look for labels on the containers. Your last line of defense when you're working around electricity is personal protective equipment such as insulating gloves and rubber soled shoes, what you need can very significantly from job to job so if you have questions ask your supervisor about the equipment that is right for what you are doing.
Some work environments have special electrical hazards, in these situations extra caution is required. For example, we've talked about the fact that water conducts electricity; its presents can create a situation that is really shocking. Never plug in cords that are wet and don't touch electrical equipment if your hands are wet. If you encounter water try to get rid of it before you begin work, if that's not possible use safety devices such as double insulated tools, ground fault circuit interrupters and PPE like rubber soled shoes to give you some protection, there are especially important in these situations.
With little room to maneuver, confined spaces can be cramped and dangerous especially if they contain live wires and electrical equipment. If you're working in a confined or enclosed space you need to be particularly careful. To avoid accident or contact with energized lines you should;
- Insulate Electric Materials
- Use Protective Shields or Barriers
Secure hinged panels and doors so that they don't release and knock you into energized lines. High voltage power lines can be extremely dangerous. So, it's important to remain at the safe distance if you're working around them, if possible the line should be de-energized to eliminate the hazard. If you're not a qualified electrical worker OSHA says, that you and any conductive objects you are holding should not come within 10 feet of a parallel line carrying 50,000 volts for higher voltage lines you must stay even further away. These clearance distances also apply to vehicles and other equipment that are near overhead lines, if you have questions ask your supervisor.
Don't use metal ladders when working near power lines, electrical wiring or energized machine parts no matter what the voltage. The metal will conduct stray electricity straight to your body and could give you a nasty shock. Use a fiber glass or wooden ladder with non-conductive side rails instead.
Flammable materials should be kept away from machinery that could generate sparks or that open flames; if you're working in the area you should avoid using tools that sparks or flame as well. Try to avoid metal to metal contacts they can also cause sparks and use non-sparking tools whenever possible. If there's been a leak of a flammable gas or vapor, don't turn equipment on or off this could create an electric arc and result in a fire or explosion. Wait until the atmosphere is clear of flammable vapors before using any electrical equipment.
If you're working with electrical system or equipment that uses more than 120 volts, you need to guard against the possibility of arc flash. An Arc Flash is essentially a giant short circuit through the air between two electrical sources or an electrical source in the ground. This result in an electrical explosion that creates super-heated plasma which can reach temperature up to 5000°F. Equipment and energy sources where there is a risk of arc flash such as panel boards, motor control centers or can do as and disconnect switches that handle high voltage loads should have arc flash warning labels attached. The best protection against arc flash is to follow normal lock-out/tag-out procedures and de-energized any equipment you may be working on.
However, some equipment must be kept running 24 hours a day, when this type of equipment needs to be service special precautions should be taken this includes;
- Arc Flash Approved PPE
- Arc Flash Designed Tools
If you encounter situations where arc flash is a potential hazard, see your supervisor before starting any work.
Dealing with an Electrical Accident
Sometimes despite of our best efforts things go wrong, in the event of an electrical accident it's important to be prepared. Never touch a person who is in contact with a live wire, this will expose you to the same electrical charge that the victim is receiving instead immediately cut the power and call for medical assistance. Electrical fires can be cause by short circuits, sparking and even a heat generated by a faulty electrical lines and equipment. So, it's important to know the location of fire extinguishers near your work area. Remember electrical fire requires Class C extinguishers. If a fire is too hot to handle get out and leave fighting it to the professionals. If there's an electrical accident a working knowledge of first aid can be invaluable. Cover minor electrical burns with a loose dry, sterile dressing and bandages. Seek medical attention to avoid any complications. Injuries that cause a lot of pain can throw the body into shock, this is when the body tries to trip the injury itself by re-routing the flow of blood to the injured area which can lead other areas of the body without the blood they need. In least cases, it's important to treat the shock immediately, if your body is allow remaining in shock for too long it can actually kill you. Wrap something around the victim to keep them from getting chills, try to calm them down if they get agitated they're shock could get worst. Stay with them until emergency health arrives. Electrical injuries are often serious in affected victim’s stops breathing. If this occurs use cpr if you're trained and administering it, keep it up until the victim starts breathing again or medical health arrives.
Working safely with electricity isn't a part time thing; it's a full time job. Let's review;
- Electrical Hazards
- Report Hazardous Conditions
- Follow Safe Work Practices
- Insulated Tools and PPE
- Be Prepared for Emergencies
Because electricity is part of so many the things that we do, we often forget that it can be dangerous. But by learning to recognize potential hazards and following proper work practices, we can work with electricity safely.