The Home Handy Person’s Guide to Electrical Safety: Electricity Can Kill You

Electricity is the invisible force that powers our homes and drives the tools that we use to repair and upgrade it. Electricity is also one of the most misunderstood energy sources encountered by the do-it-yourselfer. Most people fear it because they can’t see it with the unaided eye and people naturally fear the unknown. It can jump out and bite you when you least expect it and the bite can be fatal but it can also be controlled. Like with most fears you can overcome them through knowledge. You can transform the fear into respect and once you do that you can work with and around electricity in a safe and secure manner. This is knowledge that every do-it-yourselfer needs to gain because electricity can hurt you even if the project that you are working on doesn’t directly involve electricity.

According to the United States Consumer Safety Report published in 1995 based on statistics provided by NCHS (National Center for Health Safety) on electrocutions by consumer products, the home is truly a dangerous place for the unaware. According to the 1995 statistics, the latest statistics available, there were 550 electrocutions in and around the home because of consumer products. Out of a total of 560 electrocutions in the United States, 230 electrocutions or 41 percent were related to consumer products.

· Installed household wiring accounted for 23 percent, or 53 deaths caused by household electrocutions. You need to know what’s inside that wall you’re cutting into with your Saws All.

· Another 17 percent, or 40 deaths, resulted from defective or improperly used small appliances.

· Another 14 percent, or 33 deaths, resulted from defective or improperly installed major appliances

· Another 10 percent, or 24 deaths, resulted from improperly installed television antennas.

· Another 9 percent, or 20 deaths, result from defective or improperly installed or used lighting equipment

· Another 7 percent, or 15 deaths resulted from people coming into contact with electrical wires while working on ladders

· Another 6 percent, or 13 deaths, resulted from using defective or improperly wired power tolls

· Another 6 percent, or 14 deaths resulted from defective or improperly used farm and garden equipment

· The remaining 8 percent or 18 deaths resulted miscellaneous causes of electrocution.

With those statistics in mind let’s take a look at how electricity kills so you won’t become one of those statistics.

A common misunderstanding about electricity and electrocution.

Most people believe that it’s the amount of voltage present that makes electricity dangerous or innocuous. That’s the most common misconception. In reality, it’s the amount of current flowing through your body that electrocutes you or send you to the hospital with grave injuries. Granted that there is a direct relationship between the amount of voltage present and the amount of current that can flow through a circuit no matter whether that circuit is completed by your body or an electrical conductor it takes very little voltage to force a fatal current to flow across your heart. People have been killed by voltages that most people would consider harmless, like the 24 V (Volts) present in a residential door chime circuit. Actually a current of 1A (Ampere) or less can shock the human heart into a state of arrhythmia. That’s why GFCI (Ground Fault Current Interruption) devices which are designed to protect human beings against fatal electrical shocks are designed to trip out at 6mA (Milliamperes), 0.006A, or less.

Introduction to the Ohm’s Law

The Ohm’s Law states that the current is directly proportional to the voltage and inversely proportional to the resistance. The Ohm’s Law is represented by the formula I=E/R, where

· I = the current in Amperes

· E = the voltage in volts and

· R = the resistance in ? (Ohms)

In other words the current flowing through a circuit or through your body will increase as the voltage increases as long as the resistance presented to the flow of current remains constant.

Human physiology and electricity.

The human body contains 65 percent water by weight and water is a relatively good conductor of electricity. The internal body fluids have a resistance that varies between 300 to 1,000?. The body outer layer of skin, the epidermis, has a resistance that varies from 1,000 to 100,000? depending on its moisture content. If you’re sweating profusely, the resistance of the epidermis can drop to 1,000? in an instant. The total resistance offered by the human body is represented by this formula

R (total) = R (skin in) + R (internal) + R (skin out)

This is one of the few areas where males truly are superior to females because a current of 9A is always fatal for a female where it takes an additional amp or 10A to always be fatal to a male. That brings us to the next question, how do those current relate to electrical potential or voltage. Let’s calculate that voltage for a day when the wsweat is pouring off you like the water cascading over Niagara Falls.

R (total) = R (skin in) + R (internal) + R (skin out)

= 1,000? + 1,000? + 1,000?

= 3,000?

E = I X R = 10A X 3,000?

= 30,000 V

Very few of us will ever encounter that kind of voltage unless we start tinkering with out color television sets or computer monitors. Homes in the United States are wired for 240/120 Volts, so why does that kill people? Even with the body operating at minimum resistance, 240 Volts can only produce a current of 0.08A which is 0.8 percent of what we stated above as always being fatal.

Household voltages can kill because it disrupts the hearts internal pacemaker driving the heart into a state of fibrillation.

· Fibrillation is the fine, rapid, erratic, movements that replace the normal contraction of the ventricular muscle of the heart

· Fibrillation can be stopped by application of another controlled electrical shock, known as defibrillation, often seen in movies and on TV...

· A stopped heart can often be resuscitated with CPR techniques (cardiopulmonary resuscitation), but seldom a fibrillating heart.

The following list shows you how various amounts of current affect the human body when the current flows across the chest and through the heart.

· <0.01 A causes a tingling sensation or isn’t perceptible at all (< means less than)

· =0.02 A causes contraction of the muscles and you can’t let go

· =0.03 A disturbance to respiration or breathing

· =0.07 A extremely hard to breathe

· =0.10 A fibrillation caused death

· >0.20 A fibrillation doesn’t occur but severe burning occurs with paralysis of the respiratory system (> means greater than)

Safety rules

1. Treat every circuit that you are working on as if it were hot. This may slow you down but it will make safe working habits automatic and you won’t slip up when you have to work on an energized circuit.

2. When testing energized circuits work the way professional electricians do with one hand in their pocket. This way of working prevents you from providing a direct path across your chest and through your heart if your other hand accidentally comes into contact with live parts. If you’re using a meter learn to use an alligator clip on one of the test leads.

3. If you can’t lock a service panel door tape over the breaker and place a large sign on the panel advising other members of the household to not turn the circuit back on.

4. Where rubber sole shoes or boots

5. If you are working in a damp area stand on a rubber mat. If there is a lot of water on the floor, place the rubber mat on a wooden pallet to keep it from getting wet.

6. Watch out for overhead wires when working on a ladder.

7. Have the utility company come and mark the location of their underground lines before digging up the yard.

I always try to cover any special safety precautions to be taken with every tutorial that I publish but these will get you started off on the right foot.


Add a comment

0 answers +0 votes
Post comment Cancel
Mark Cruz
189 answers Posted on Mar 12, 2012
This comment has 0 votes  by
Jerry Walch
246 answers Posted on Apr 20, 2009
This comment has 0 votes  by
Charlene Collins
61 answers Posted on Apr 20, 2009
This comment has 0 votes  by
Sam Montana
1,860 answers Posted on Apr 13, 2009
This comment has 0 votes  by

Related Articles

Installing a 220VAC Circuit For Air Conditioning Condenser Unit

When it comes to air conditioning installations, there is usually very little that the homeowner can do. However if you are relatively handy you can install the electrical service to the outdoor condenser unit and then leave the refrigeration work to the professionals. Remember that you should alwa...

How to Size a Circuit Breaker and Wire Sizes

Circuit breakers are over current protection devices (OCPD) that are designed to break the circuit and prevent equipment damage or fire. When too much current runs through a circuit the heat in the circuit exceeds the breaker's load rating and it trips, shutting off the electrical power. Proper sizi...

Troubleshooting a Low Voltage Lighting Transformer

Low voltage lighting transformers have become commonplace in many of today’s homes with the increase awareness in energy efficient lighting systems and decorative accent lighting. A low voltage lighting transformer is a device that converts the standard 110V or 120V household voltage to a lowe...

How To Wire A Fan/Light Switch

Installing a ceiling fan/light combination is a common home improvement project. The part of these projects that confuse many new do-it-yourself persons is how to wire the electrical wiring, so the fan and the light can be controlled by separate, wall-mounted switches. Many handy persons who are rea...

How to Replace Low Voltage Lighting Transformer

Sometimes when a light is not working it isn’t always the bulb. Some recessed lights use a transformer that is mounted to the light above the ceiling. Low-voltage recessed lights use transformers to convert high-voltage electricity to a low-voltage power supply, usually 120V down to 24V or ...

How to Wire a Switched Outlet - Half Hot Outlet

Many times people would like to have an outlet controlled by a switch to be able to turn on a lamp or some other device. Sometimes they have a switched outlet, but it is in the wrong location, or they would like to plug in another device that they would like to remain on all the time. A situation li...

How to Hard Wire a Dishwasher

One of the few appliances in the kitchen that is wired directly to a dedicated circuit is the dishwasher. Aside from the heating element which draws a considerable amount of amperage, the dishwasher is connected to a water source which can pose an elevated risk to shock and circuit overload.  H...

Tricks of the Trade: How to Run Cable Behind Baseboards and Casings

One of the most frustrating things about fishing wire through the walls of older homes is encountering unexpected obstructions. Older homes often have one or more 2 X 4's running horizontally between studs as fire stops. Running wire through such a wall space is very time consuming and labor intensi...

What to Do when a Circuit Breaker Trips Intermittently

A circuit breaker that trips open intermittently may be indicative of a circuit overload or an intermittent short circuits. Two reasons a circuit breaker trips open are circuit overloads and short circuits. Circuit breakers, like the older, Edison-based fuses, are designed to protect electrical writ...

How to Run Electrical Wiring Underground

At some point you may want to have power in a garden shed or detached patio or some other area in your yard. Instead of running an extension cord to that particular location you may want to install an underground conduit or direct burial electrical cable to provide a more permanent solution. Consult...

How to Install or Replace a Doorbell Transformer

Standard doorbells are not powered by 120 volt electric typically used in the home. Most doorbell chimes use a transformer to step down the voltage from 110/120 VAC (volts alternating current) to 10 to 24 VAC. A small transformer is installed in the basement near the door or on the side of the panel...

How to Wire a Lamp

One of the most basic electrical fixtures in your home is a floor or table lamp. If you ever have to rewire a broken lamp or socket, there are some important lamp socket wiring basics you need to understand to correctly connect hot and neutral wires when you replace a lamp switch and socket to keep ...

How to Troubleshoot a Tripped Breaker

Most of the time a, circuit breaker trips people simple go to their electrical panel find the offending breaker and reset it. But what happens when the breaker does not reset, or trips often, you can troubleshoot the problem yourself and depending on the problem, repair it or hire an electrician to ...

How To Test Start And Run Capacitors

Start and run capacitors are found in many single-phase motor circuits and is one of the biggest causes of motor failure. They are found in your refrigerator, deep freezer, air conditioner, furnace, and many of your motor driven power tools. A starting capacitor that has failed or a starting capacit...

How to Replace Fluorescent Light Ballast

Fluorescent light fixtures are energy efficient over the long run, but bulbs and ballasts are expensive replacement items. Typically when the light bulb flickers continuously or the fixture begins to hum you need to replace the ballast. The repair will only take about 10 minutes. New ballast prices ...

DIY ELECTRICAL: An Introduction to Wire and Cable

Since 1930, homes have been wired using nonmetallic sheathed cable (NMC). The original NMC contained two or more rubber insulated conductors within a rubberized fabric jacket. These early NMC wiring systems contained no system grounding conductors. Modern NMC, known as Romex Cable in the trades, has...

How to Install an Outdoor Receptacle

You can install an outdoor electrical receptacle safely and quickly by using a through-the-wall technique. It is important to understand wiring basics, use proper safety precautions and have your work inspected by your local building code official. This method works with homes that do not have stone...

Problems with Your Home's Neutral Wiring

Most homeowners know that their electrical wiring g carries 120 volts of AC (Alternating Current) electricity to outlets, appliances, and switches. They may also know that the black, and sometimes red, wire is the hot wire and the white wire is the neutral. In almost every case the black wire carr...

Homeowner's Guide to Electrical Problems - House Meter Socket

A major component in your home’s electrical system is the main electrical feed coming into the panel board.  Between the utility wires and the panel board is the electric meter which is typically installed in a separate meter box, but sometimes they are installed in a panel board with a s...

How to Move an Electrical Outlet or Light Switch

Electrical outlets and light switches sometimes must be moved during a remodeling project. This often happens when a closet has been added or a door moved. Many times this will leave the light switch on the opposite wall or a large section of the room without an electrical outlet beca...

DIY Appliance Repair: How to Test the High Voltage Components of a Microwave Oven

Once you have removed the outer shell of the microwave oven, you will find a schematic diagram similar to this one affixed either to the inside top or end pieces of the wraparound shell piece. At first glance most of the symbols used on this diagram will probably mean nothing to you, unless you h...

Pros and Cons of the Smart Grid - a National Power Grid for the U.S.

There has been much talk about the initiative to create a “Smart Grid” for the United States electrical power grid. The problems created by the Smart Grid may be equal to or greater than the problems it is meant to solve. A power network utilizing present computing technologies will eli...

Repair Underground Wiring with a Splice Kit

As more and more homeowners add exterior lighting, receptacles, dog fences, and irrigation systems, there is a greater chance for damaging the direct burial, also called underground feeder (UF) cable, underground electrical wires. Instead of digging up the wire and replacing it, you can easily repai...

DIY Electrical: An Introduction to Light Switches

Single—pole light switches are used when the lights are controlled from only one location. Three—way light switches are used when the lights are controlled from two locations. Four—way light switches are used in conjunction with two 3—way light switches when the lights are to...

How to Extend a Coaxial Cable Line

When cable was initially run to homes in the United States only one cable jack was normally installed. As time went on, people often added more televisions that required additional jacks. If you need another jack for a cable TV signal; set up a computer network in your home; or hook up an FM radio o...

How to Fix Buzzing, Noisy, and Flickering Lights

From time to time we have all encountered flickering fluorescent lights or a humming dimmer switch that are more annoying than dangerous. There are plenty of small electrical light problems that you can fix easily without having to hire an electrician and here are a few easy repairs that you can h...

How to Choose the Correct Size Electrical Box

There are many instances when you need to add or move an electrical box during a minor renovation or repair. Whether you are working in your garage, attic, or kitchen you need to know that there is a limit to how many wires you can safely place in an electrical box. Keep in mind that not all electri...

How to Install An Exterior Floodlight

A simple and effective way to improve the safety and security of your home is to add a motion-sensor floodlight over your garage or other area of your home. Many models are available that have a built-in motion sensor which activates the light whenever something crosses its field of vision. The i...

How To Wire A Switch Leg

If you live in an older home, there is an excellent chance that ceiling mounted light fixtures are controlled by pull chain switches. The problem with fixture mounted pull chain switches is that you have to stumble through a pitch black room and fumble around the find the pull chain. It is mush easi...

How To Diagnose and Correct Wiring Problems in Receptacles

Improper or careless wiring of receptacles, also referred to as outlets, is the most common electrical defect found in a typical home. Improperly wired outlets are a potential shock hazard and can cause electrical equipment to use more electricity and fail prematurely. Most of the electronic devic...

DIY Decorator Light Switch Covers with Sharpies

If you have ever seen those cute decorator light switch covers and wanted some for your home you don’t need to buy them. They are priced anywhere from $7.99 and up and are really not that hard to make yourself. The cost for a box of plain white light switch covers from Home Depot is a little...

Facts About Dimmers Switches

Dimmer switches are an effective means to for saving energy and extending bulb life. Along with the practical benefits of placing a light fixture on a dimmer switch, most people utilize dimmers to create visual effects and ambience in a room. Dimming Bulbs 1. Incandescent 2. Halogen The most com...

How to Install an Outdoor Lamp Post

Learn how to install an outdoor lamp post; details include digging a post hole, setting the post and wiring the lamp. Whether you want to add a lamp post alongside your front entry or you need to replace an outdated one, this article will provide the necessary steps to complete the job. Not only do ...

How to Properly Wire a 3-Way Switch

One of the most frustrating things to do is to troubleshoot a 3-way switch that is not working properly. Sometimes the light switch is replaced and the wires were not coded properly to let subsequent people make future replacements easily. This occurred most often in the past when electricians used ...

Recessed Lighting Safety

Recessed lighting has been a part of many homes since the 1970s. Currently Underwriters Laboratories (UL) has a list of approved features for lighting safety. Older recessed lights in your home may require special attention if you are installing new insulation or higher wattage bulbs than the fixt...

The DIY Electrician's Guide to Troubleshooting Dead Receptacles

Knowing how to troubleshoot, isolate and repair electrical problems is what separates the men from the boys-if you’ll excuse the non-politically correct expression-when it comes to electrical work. Almost anyone can install a new receptacle, light switch, light fixture ceiling fan, etc. but...

How to Hang a Chandelier

You can easily replace outdated light fixtures to improve the look of a room. A new ceiling light or chandelier can add style, create a focal point, or improve the lighting of a room. Even though you may not be comfortable working with electricity, switching out old fixtures is safe as long as you p...

How to Use a Circuit Breaker Finder

Have you ever tried to locate the circuit breaker controlling the branch circuit that you want to work on? If you have a relatively new home, the circuit directory may be correct so finding the right breaker is a snap. The circuit directory on breaker panels in older homes is illegible or missing. T...

Tracing and Repairing Speaker Wire in Your Wall

Tracing and repairing speaker wire in your wall is not difficult. You just need a few tools and some patience. If you have moved into a home with speaker wire already weaving through your drywall you may want to take advantage of that and hook up speakers in the various rooms. You will have to trac...

Arc Fault Circuit Interrupters - AFCI Reduce Fire Hazards

An Arc Fault Circuit Interrupter, AFCI for short, is an electrical device that shuts off power to a circuit when arcing conditions are first detected. Normal circuit breakers open in the presence of a short and may not trip before a fire has begun due to arcing. Up to 40,000 home fires can be associ...

How to Light Artwork

If you have seen artwork displayed in a home, gallery, office, retail or other location, you may have noticed how much lighting impacts the presentation. Lighting artwork properly is essential to experience and understand the complete work of art and all of its illustrious detail. Artwork comes in a...

How to Repair A Solar Walkway Light

Many homeowners have installed economical solar powered lights to illuminate their front entrance walkway. Besides the low initial costs, the lights are easily relocated or removed and stored away for the winter. This article will describe how to repair or replace the solar light fixture. LED...

Common Mistakes Made By The DIY Electrician

There is nothing more rewarding then to be able to tell others that you did it yourself, knowing that you did it correctly. The problem is that with electrical work, just because something works does not mean that you have done it correctly. Professional electricians serve a rigorous apprenticeship ...

DIY Electrical: How to Rewire a Floor Lamp or Table Lamp

Restoring table lamps and floor lamps to like new electrical condition provides a completely safe environment for the beginner to learn essential electrical skill sets. Besides offering shockproof, hands-on learning, you can furnish your home with some really beautiful lamps found at garage sales an...

Electrical Tips and Techniques

Some homeowners may understand a few basic wiring principles for switches, outlets, and small fixture installation. Here are a few tips and tricks you can use that will make the job go smoothly and produce a better finished product. Fishing a Wire in a Wall When fishing a wire through a wall, use ...

New Ideal SpliceLine In-line Connector the Optimal Butt Splice

How many times have this happened to you? You have to replace a duplex receptacle because it is no longer holding a plug securely. You have a receptacle in your shop, so you figure you will be able to replace the old one in fifteen minutes. Plenty of time before you have to leave for work. Your wife...

How to Install a USB Wall Receptacle

You probably haven’t realized it, but there is a product that has been on the market for a few years now which combines the convenience of a USB charger with a traditional wall receptacle.  This allows you to charge iPods, iPads, MP3 players, cameras, and smart phones without using the st...

Light Bulb and Lighting Terms

Here is a comprehensive list of terms that you can use for lighting projects in your home and business. Accent Lighting Directional lighting to emphasize a particular object or draw attention to a display item. Ambient Lighting The general lighting present in an area --excluding task lighting an...

How to Install a Bathroom Fan Timer Switch

A simple electrical device can save you a lot of money in electrical, heating and cooling costs, they will also improve the indoor air quality (IAQ) or your home; an automatic timer switch. You can install these devices when upgrading your bathroom or add them to your existing exhaust fan to automat...

How To Install Track Lighting

Track lighting installation has gained steadily since its introduction to the residential market because it track lighting combines a mix of task lighting and directional lighting. Track lighting is also relatively easy for the do it yourselfer to install, especially if you are replacing existing li...