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Home Wiring Safety Tips from UL

Tuesday, June 27, 2006

June 27, 2006 (WLS) -- Each year 32,000 home fires in the U.S. are associated with faulty electrical systems and lighting equipment, resulting in 950 injuries, 220 deaths and $674 million in property damage.

More than a third of U.S. homes are 50 years old or older and when you think of the number of electrical appliances installed in the last five years - home theaters, computer systems, etc. - let alone the advances in the last 30 years (microwaves, A/C, coffeemakers, blow-dryers), it's no wonder home electrical systems are overtaxed, says John Drengenberg of Underwriters Laboratories in Northbrook. www.ul.com/consumers.

He says there are five things everyone homeowner should know to keep your home and family safe:

Before buying a home, have someone who is certified in electrical work inspect the electrical system. Contact the National Association of Certified Home Inspectors (www.NACHI.org) for referrals.

Know your limits when remodeling work includes wiring, and consider calling in a professional to assist.

Drawing more current through an electrical system than it was designed for will eventually cause a safety hazard-even if fuses aren't blowing or circuits aren't tripping.

Electrical shocks, hot outlets and hot plugs, burning smells and flickering lights are signs that your home's wiring system needs professional attention.

The National Electrical Code® says extension cords were never meant to be a permanent replacement for wiring and should not be fastened in place.

Wiring Safety Tips

Unplug appliances when not in use.

Look for the UL Mark on all products. It means that samples of the product have been tested for safety.

Make sure outlets are not overloaded.

Check electrical wires and cords on appliances, tools, lamps, etc. to make sure they're not worn or frayed.

Never run electrical wires or extension cords under carpets or heavy items.

Never bunch electrical wires or extension cords behind a hot appliance

Use outlet plug covers to prevent children from inserting objects into outlets.

Extension cords are meant for temporary use only.

Look for the UL Mark on extension cords that you purchase. The UL Mark means that representative samples of the cord have been tested for foreseeable safety hazards.

Store all cords indoors when not in use. Outdoor conditions can deteriorate a cord over time.

Never keep an extension cord plugged in when not in use. The cord will conduct electricity until it is unplugged from the outlet.

Most newer, indoor cords with more than one outlet have covers for the unused openings-use them. Children and pets face serious injury if they chew on unused outlets or stick sharp metal objects into the openings.

Do not use extension cords that are cut or damaged. Touching even a single exposed strand of wire can give you an electric shock or burn.

Home Wiring Warning Signs

Underwriters Laboratories (UL) recommends that homeowners and prospective buyers pay close attention to several electrical safety warning signs. Owners and/or buyers are urged to talk with a licensed/qualified electrician or consult a home inspector if any of the following are observed:

Shocks. A properly wired and grounded electrical system will protect you from most potential electrical shocks.

Overloaded outlets. Too many appliances plugged into a single outlet could indicate your house may not have the required number of outlets. The National Electrical Code requires that outlets be spaced every 12 feet of running wall space, or one on each wall of the average 10-by-12-foot room. Kitchens typically require outlets spaced every 4 feet along the countertop.

Flickering/dimming lights. This could indicate loose wire connections, overloaded circuits, improper wiring, or arcing and sparking inside the walls.

Hot to handle. If your receptacles, switch plates, cords or plugs are hot and discolored and you can't keep a hand on them for more than five seconds, you may have an overload or product malfunction.

Shrinking/wavering screens. TV screens or computer monitors that shrink or waver when a large appliance is turned on could mean you have too many appliances plugged into one circuit, or that your home needs additional electrical capacity.

Unusual smells. Burning metal or plastic smells may indicate a loose connection, malfunctioning switch, light fixture, broken connection, overheating components, arcing or sparking inside the walls, damaged wire or other potential hazards.

Wobbly plugs. This could indicate that the outlet is outdated and worn. It should not be used and be replaced immediately.

No three-pronged outlets. In new housing, the National Electrical Code® requires three-pronged outlets or ground-fault circuit-interrupter (GFCI) protection everywhere on your property, including outdoors. If your house is lacking both these items, your system is likely outdated

Blown fuses/tripped breakers. Replace fuses and reset circuit breakers. If they blow or trip again, a problem exists somewhere.

Permanent extension cords. Extension cords are meant for temporary use only. Any products plugged into extension cords for long-term use is an indication your house does not comply with current NEC® requirements.

Source: Underwriters Laboratories (UL)

Common DIY Wiring Mistakes

If spring sends you into remodeling mode, you might want to consider consulting the experts before you migrate to the nearest Lowes or Home Depot.

DIY projects are very satisfying to complete, says John Drengenberg, consumer affairs manager for Underwriters Laboratories (UL), but there are risks when it comes to electricity.

"Mistakes can be costly-or even deadly," he said. "The first and best safety tip is to call in an expert rather than be your own electrician."

UL engineers are getting a first-hand look at DIY wiring mistakes as part of a multiyear study by the Fire Protection Research Foundation in Quincy, Mass. Begun in 2003, the FPRF's Residential Electrical System Aging Research Project studies the wiring of condemned homes in several U.S. regions to determine how electrical systems hold up over the decades.

Although it is too early in the study for researchers to identify trends, mistakes typical of DIY projects have been easy to spot, said John Drengenberg, consumer affairs manager for Underwriters Laboratories (UL). According to UL, some of the most common DIY wiring mistakes are:

Working with a live wire
It may seem perfectly obvious, but thousands of DIYers receive electric shock injuries each year. To avoid becoming a statistic, always turn off the circuit breaker (or remove the fuse) before working on or replacing electrical equipment. If you have a pre-1940s home, history suggests that you probably have more than one breaker box, or panel board, as electricians call them.

In the '40s, many utility companies would upgrade service from 60 amps to 100 or 200 amps without charge, Drengenberg explained. The utility would install an electrical meter and a circuit breaker box. Then the homeowner would have an electrician come out to wire those circuits, and the company made its money back from the increased use in electricity.

"We've done six or seven houses in Alabama," he said, "and it's common to all of them."

Using the wrong light bulb
Most lighting fixtures have a sticker on the socket that tells you the proper type and maximum wattage of the light bulb to use. Installing a different type of bulb, or one with higher wattage, will not only make the room brighter, but also could damage the lights and cause a fire. Heat is usually the catalyst in this case because the higher the wattage, the hotter the bulb and the hotter the wire that goes to the lighting fixture.

Not being grounded
For optimal safety, receptacles should be wired with the proper grounding and polarity. Generally, the three-pronged outlets signify an effective ground path in the circuit. However, homes built before the mid-1960s probably won't have a grounding path, and simply replacing the existing outlet with a three-pronged outlet won't give you one.

"You see instances of this in homes with older wiring," Drengenberg said. "It's no worse than if you plug your two-pronged devise into a two-pronged outlet, but it does give the homeowner a false sense of security."

Wiring with a grounding path usually has a copper grounding wire with the cable, he said. In older homes, wires are just the black and white ones. If you are uncertain about whether your home's wiring is grounded, inexpensive UL Listed outlet circuit testers are available to test the circuit for proper grounding and polarity. If your outlet is improperly grounded, call an electrician before moving forward in the project.

Splicing, splicing, splicing
Always make sure your wiring size and type match. Splicing wires by simply twisting them together and covering them with electrical tape is rarely a good idea. Instead, use wiring that is suitable to your home's wiring and house wiring connections in metal or plastic boxes.

The metal or plastic receptacles decrease fire risk, Drengenberg said.

In one Alabama home excavated by researchers, someone had installed lighting switches and none were properly housed. The connections were flush against the wall-back. Without the receptacle to contain the electrical spark, a power surge, or hot wire, could have lead to a fire.

Also keep in mind that circuits protected by 15-amp fuses or breakers should be wired with No. 14 AWG copper wire minimum. For 20 amps, use No. 12 AWG minimum size copper wire. Other guidelines apply, so if you expect to do any splicing, seek advice-if not professional help-before you begin.

Hooking new lights to old wires.
Most light fixtures are marked with instructions for supply connections, such as "Use wire rated for at least 90C," which refers to the maximum temperature-90 degrees Celsius or about 200 degrees Fahrenheit-under which a wire's insulation can safely be used. Again, if you have an older home (pre-1984, in this case) the wiring may have a lower temperature rating than the new luminaire. This isn't something most DIYers even think to consider, Drengenberg said.

"It probably won't burst into flame immediately," he said, "but it does increase the risk of a fire."

To avoid that risk, check your wire rating first, and either upgrade the wiring or buy fixtures within the supply connection range.

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