Electrical Systems & Hazards

Contents:

• Preventive maintenance for your electrical system
• Electrical safety around the house
• When old wiring needs replaced
• More power to ya: Sizing to meet your needs
• GFCIs (Ground Fault Circuit Interupters)
• How to change a fuse

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Preventive Maintenance for Your Electric System 

Preventive maintenance for your home may save you the stress of having to spend your weekend off addressing a problem and could save you the considerable expense often caused by "crisis" situations.

The following recommendations for your electric system will keep problems to a minimum and increase the overall safety, appearance and good working order of your home.

1. Check the condition of lamp cords, extension cords, and plugs. Replace cords, etc. at the first sign of wear or damage. The rating of lamp cords and extension cords is rarely as high as the permanent wire, which was installed in and throughout the walls of the house. If these cords are used for an appliance or appliances, which overload the capacity of the cord, but not the wiring in the wall, the extension cord will become warm or hot. Continued use will deteriorate the insulation and create a fire hazard. Lightweight should never be used for high draw appliances (e.g., hair dryers, power tools, etc.).
2. Check all portable appliances and power tools for loose or frayed wires, and has them repaired before using.
3. Check all exposed wiring (e.g., in an unfinished basement or garage, etc.), switches, and receptacles for wear, damage, or malfunction. Have these components repaired or replaced immediately.
4. Check the exterior service cable. Deteriorated insulation allows water to enter and creates a potential fire hazard. Water may follow the wire and corrode contacts at the meter socket and/or the panel box. A deteriorated service cable should be replaced.
5. Check for distribution overloads. If fuses blow or circuit breakers trip frequently, contact an electrician to determine the cause and to make the necessary repairs. The size of the wire dictates he size of the fuse or circuit breaker (e.g., a 14-gauge wire should be protected by a 15-amp fuse or circuit breaker, a 12-gauge wire should be protected by a 20-amp fuse or circuit breaker, and a 10-gauge wire should be protected by a 30-amp fuse or circuit breaker).
6. Check exterior lighting to make sure their weatherproof boxes are watertight. Outdoor circuits and receptacles in bathrooms and on kitchen counters should be protected by a supplementary circuit device called a ground fault circuit interrupter (GFCI). A GFCI operates on "balance" in the circuit as compared to circuit breakers and fuses, which respond to "quantity." GFCI devices operate with a transformer, which senses the balance of current in a given circuit. If current is diverted to a foreign ground the GFCI device will sense it and open the circuit. A foreign ground is any place that is not the intended or anticipated ground (i.e., A hairdryer or radio falls into a tub or basin of water. The current that leaves the circuit creates a differential and causes the circuit to open or turn off.). The sensitivity is almost instantaneous.
7. Check areas in the basement, attic, or garage where wiring is open to view. Look for the letters "AL" or the word "aluminum" stamped on the outside jacket of the wire insulation. If the wiring is aluminum, have a qualified electrician check the receptacles and switches to make sure the terminals are acceptable. Aluminum single-conductor wire was used in residential housing from 1964 to 1975. If problem devices or connections are found, CO-ALR devices should be installed.

Most of the changes or repairs highlighted above require little time and money. The safety benefits far outweigh the cost. A licensed electrician for safety reasons should perform electrical repairs and replacements.

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Electrical Safety around the Home

Home is where the heart is, says the old adage. Unfortunately, homes are also where the hazards are.

The following is a list of potential electrical fire hazards along with ways to correct the problems: 

1. Extension cords are typically smaller than the amperage rating of the permanent wiring that they extend. This can cause the wire to heat up long before the fuse blows or circuit breaker is tripped.
2. Extension cords should not be put below carpeting due to possible damage. Nor should they be installed permanently because the staples, etc. could damage them. This feel of "permanence" could create an atmosphere where it could be used for appliances that will overload the wire. Extension cords should not be installed through floors or walls because of their vulnerability to damage.
3. Wire splices should only be installed in prescribed boxes and mechanically secured. Exposed splices may become loose and cause arcing and excessive heat and deterioration.
4. Service entrance cables with deteriorated outer covering will allow water to enter and may follow the cables into the meter socket and possibly into the main panel box. This will cause corrosion. It may also cause circuit breakers to freeze in the "closed" or "on" position. This is a significant fire hazard. The service entrance cable should be replaced when the outer covering is deteriorated.
5. Broken or loose switches and outlets should be replaced because their dependability is suspect and the occupants may be exposed to shock.
6. Breaking or cutting off of the ground prong of a three-prong plug will not affect the operation of the appliance. However, it does compromise the safety of the user.
7. Dimmer switches should be checked for excessive heat. The rating of the dimmer should always be higher than the total wattage of the bulbs it serves. Dimmers with ratings 50 percent to 100 percent above the total bulb wattage are desirable.
8. Light fixtures and related shades and covers can deteriorate quickly if the bulbs used in the fixture are larger than the fixture rating. Fires can result.
9. Circuit breakers that will not trip or are "buzzing" are a problem. It may be related to moisture, corrosion, or inexpensive or incompatible equipment, but it must be corrected as soon as possible.
10. Electrical equipment, wiring, panels and fixtures should never be installed in areas with excessive relative humidity unless the equipment is designed for this use. These situations are a significant safety hazard and should be addressed as soon as possible.
11. Incandescent lighting close to clothes or other combustibles in closets may create a fire hazard. Bulbs should have covers and should be a minimum of 12" from combustible material.
12. Fuses and circuit breakers have nothing to do with electricity. Their only purpose is to protect the wire they are attached to by keeping it form overheating. Oversized fuses or circuit breakers do not enhance the electric circuitry or the equipment they serve. Fourteen-gauge wire is rated for 15 amps. Use no more than a 15-amp circuit breaker or fuse. Twelve-gauge wire is rated 20 amps. Ten-gauge wire is rated 30 amps. Some people may be under the impression that the larger fuse/circuit breaker will allow that line to hold more. The integrity of the wire is compromised from overheating. The entire circuit is compromised, not just at a fixture or connection. This should never be allowed to happen. If it does, it should be corrected as soon as possible.

Other areas of concern include double-wired circuit breakers, reversed polarity at outlets, ungrounded outlets, the lack of ground fault circuit interrupter (GFCIs) at wet areas, and miscellaneous workmanship compromises. These are all safety-related situations and should be addressed.

A licensed electrician can evaluate your system for usually less than $100. He should be able to locate problem areas and be able to offer you options.

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 When Old Wiring Needs Replacement

We've all heard the stories about house fires due to bad wiring. They get considerable attention because they are not common. Most occurrences are in older homes.

The main concern with wire safety is the insulation around the metal wire or conductor, not the wire itself. The insulation is like the weak link in the chain. If it is good, the wire will be good. If the insulation is bad, this is probably because there was an overload on the wire.

The two different types of insulation, plastic and cloth will react differently when an overload takes place. Plastic insulation will become distorted and cloth will become hard and brittle. Cloth insulation is older and is the kind about which you should be more concerned. The overload process can happen slowly, over time, or in an instant. If the insulation is unable to protect the wire and it becomes exposed, a fire could result.

The easiest way to know the condition of the wire is to bend it where it has not been bent before. If you can bend it 90 degrees and the insulation does not crack and expose the conductor, the wire is acceptable.

If you expose the metal conductor at 90 degrees or less, the wire is less than acceptable and would be classified as marginal or poor by the trained home inspector. Marginal means the wire is less than acceptable and needs attention in the near future. The situation is similar to a bald tire on a car. The tire will probably stay intact for another few thousand miles if there are no serious bumps in the road. There is no guarantee, though, and there is somewhat of a risk involved.

If the insulation around the wire cracks or breaks when you bend it, the wire is considered poor and needs replacement immediately due to an imminent danger it poses. If the wire were related once again to a tire on a car, the exposed cords on the tire would be showing in this case. Driving on this exposed tire would be a much greater risk.

Generally, if house wiring has the proper size fuses or circuit breakers, it is dependable for 70+ years. In their initial installation, the overwhelming percentage of homes is properly protected. But, in the majority of homes that have fuses that are more than 30 years old, there probably are some compromises.

If replacement is needed, you can expect to pay approximately $125-$175 per circuit. It is generally in homes 50 years or older that a serious rewiring job is needed and, fortunately, this is rare. If you have any questions about your wiring, call a professional home inspector or a licensed electrician.

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More Power to Ya

Tim "The Toolman" Taylor from the TV show Home Improvement would agree that today’s homes need considerably "more power" than homes did 25 years ago. We barely had hand-held hairdryers two decades ago. Because of this evolution, numerous electrical systems are obsolete.

In addition to the frustration of not having enough power, overloads on the electrical service present a serious fire hazard.

To figure out how much current a home needs, you have to know the size of the electrical service and the wattage of the equipment present. Knowing how a single-phase service delivers the current to 120- and 240-volt circuits is also helpful. (Single phase is the typical residential service.)

There are two 120-volt poles, which are the parts of the panel box that receive power from the utility company. To energize a 120-volt branch circuit, you only use one of these poles. As you add 120-volt circuits, you alternate with the right and left poles. The 240-volt circuits use both 120-volt poles to service large appliances like a clothes dryer, water heater, range/oven, and central air conditioner.

The following is a rule of thumb to help determine the service requirements for a house:

1. Figure out the square footage of the living area.
2. Multiply the square footage of the living area by three watts for the lighting and small appliance loads.
3. Calculate the total wattage used by the major electric appliances (e.g., dryer, range/oven, water heater, central air conditioner, and electric heat). Figure the first 10,000 watts at 100% and the remaining wattage at 40%.
4. Add these figures together and divide by 240. The answer should reflect your necessary amperage or service size.

If your maximum usage is close to or above the rated amperage of the service, you should consult a licensed electrician for your best options.

Here is an example of a typical house situation that you can use as a reference:

25,640 divided by 240 = 106.84 amps. The service size should accommodate 107 amps. This means you would need a 125-amp service. The 150-amp service is a more likely choice and somewhat standard size.

Visions of the numbers listed above may have brought about bad memories from Jr. High math class, but figuring out your amperage is an interesting task and really not difficult.

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Ground Fault Circuit Interrupters are a Safe Buy

We've all heard the stories of someone getting a serious shock or perhaps even fatally injured when an electric radio or hairdryer accidentally falls into a basin or tub. What many of us do not know, however, is that since 1986, countless lives may have been saved thanks to a $25 ground fault circuit interrupter (GFCI), a device that would shut of the circuit in situations like this. Nonetheless, there are still millions of homes across America without these lifesaving devices.

In 1986, an ordinance in the National Electric Code was passed those required contractors to install GFCIs in new residential construction.

Although they're small, they play a big role in every home in which they're installed. Here's how the GFCI works:

Current flows through appliances at a consistent rate. This is why you won't see a light bulb dim one minute and glow brightly the next, unless you have a dimmer, which can manually manipulate the amount of current flowing through the circuit. Minus the dimmer, though, the intensity of the current in the light bulb circuit will stay the same.

A GFCI senses this flow, or balance, of current. If the current that returns to the neutral in the panel is different from the current from the source or line, the GFCI will open the circuit and shut off the current to that circuit. The GFCI is both incredibly sensitive and fast. It detects changes in current at .5 milliamperes and reacts at the speed of light. This speed enables one to be protected at the moment the hair dryer hits the water.

Without a GFCI, when the hairdryer hits the bathwater, the person in the tub becomes the conduit the electricity travels through en route to a ground such as the metal fixtures in the tub, spigot or drain.

GFCIs come in two forms: The one in an outlet in a bathroom or kitchen and the one incorporated with the circuit breaker in the electric panel box. With new construction, they are installed in the bathroom, kitchen, exterior fixtures and any area adjacent to water. One GFCI can protect several locations if they are on the same immediate circuit. A GFCI on one circuit will not protect the areas that are on a different circuit in the home. The only negative to a GFCI is that in very humid situations, moisture can build up in bathrooms and occasionally trip the circuit. This rare inconvenience is far outweighed, though, by the protection they offer.

The cost for a GFCI varies depending on the type, but generally falls between $20 and $30, not including installation, for which a licensed electrician is recommended. The electrician's fee will range from $60 to $100 per unit, but the peace of mind you'll have knowing the GFCIs are installed correctly should outweigh the additional cost.

GFCIs are not circuit breakers or fuses. Circuit breakers and fuses operate on the amount of current that passes through the device. They don't measure if the current is balanced. Conversely, the GFCI does not measure the amount of current, but rather reacts when the amount of current is different from the source to the neutral.

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How to Change a Fuse

Your son has his new compact disc blasting in his bedroom as he plays a Nintendo game. Your teen-age daughter Susan is blow-drying her hair as she watches "Beauty and the Beast" for the umpteenth time. There are clothes in the dryer and the air conditioning is on. A pot of stew is simmering on the electric range, and Mom is watching "Jeopardy" on the kitchen television while ironing. She is just about to hear the "Final Jeopardy" question ... when the fuse blows! The only problem is that dad is working late at the office and he's the only one who has ever changed a fuse. Sound familiar?

Changing a fuse is actually quite a simple procedure. But for those who have never done it, it can be intimidating because they have to approach the electric panel. In their minds, electric panels equal hair-raising shocks.

If your home was built around 1950 or before, you probably have fuses. If it was built after that time, you probably have circuit breakers. Although they look different, they serve the same function _ to protect the wire. Fuses are glass with a lead band that is visible through the glass base and screw into a fuse socket. Circuit breakers look like switches.

If the lights go out or the appliance or tool stops operating, you probably blew a fuse or tripped a circuit breaker. Switch off the appliance or tools that were running. You don't need to turn everything off, but enough to reduce the load. Then go to the panel box, open the cover and look for the glass fuse with the black burn mark in the center.

There is a lead strip approximately 1/2'' to 3/4'' long. If you can see an intact lead strip, this is not the fuse that is blown. Unscrew the burnt-out fuse and replace it with the same size, or rating, fuse. The fuses are color coded and numbered as follows: blue fuses are 15 amps, red or orange fuses are 20 amps and green fuses are 30 amps.

It's also important to note that the fuses in the sockets could be the wrong size. You need an electrician to remove the cover and check the wire sizes. The following will indicate which fuse sizes are needed:

• 14-gauge wire = 15 amps
• 12-gauge wire = 20 amps
• 10-gauge wire = 30 amps

Normally, 14-gauge wire is the smallest wire in the panel; 12-gauge is a little thicker, and 10-gauge is a little thicker still and is normally used on 220-volt circuits. You may be able to read the wire size on the outer insulation of the wire, or you can buy a wire gauge from the local electrical supply store for just a few dollars.

We do not recommend that you unscrew the panel box to look at the wire sizes. You can open the front of the panel box without fear of a shock. If, however, you unscrew the cover off the panel box, you run a considerable chance of getting a shock. You can also get a shock by sticking your finger in the fuse sockets.

After you change the fuse, plan to set an appointment with a licensed electrician so he can review your panel box and create a ledger of the proper fuse sizes. This will be helpful should a fuse blow in the future.

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