This Old Wiring

It may be time to upgrade your home's electrical system

Museum piece. This is knob and tube wiring, a system that used porcelain tubes to route wire through framing members and knobs to support spans of wire in attics and under floors. It was common in the early part of the 20th century.

Dimming or flickering lights. Frequent blown fuses. Shrinking TV pictures. Outlets or extension cords warm to the touch. Experience any of these?

All these little symptoms may be signs of a much larger problem lurking behind the walls in your home-an outdated or inadequate electrical system. If your home is more than 30 years old, it may be time to consider upgrading.

Even if your home's wiring and related connections are in perfect working condition, they may still come up short when it comes to delivering the amount of power needed for today's electric lifestyle. No one dreamed four or five decades ago we'd depend on so many modern electric conveniences today. That means homes built in the 1960s and earlier could probably at least use a few more receptacles.

Dr. Jim Allison, retired University of Georgia Biological and Agricultural Engineering professor, recommends several components of your home's electrical system to inspect and repair or upgrade if needed:

• Grounding. The primary purpose of the home's grounding system (not to be confused with neutral wires) is people protection. Check the grounding rod outside your home and the clamp that holds the bare copper wire to the top to make sure the connection is secure. Ideally, the rod should be located beyond the drip line of the roof so it rests in moist soil.

  "I've seen all kinds of things," says Allison, "including a number 12 wire used to connect the ground rod to the wiring system. A number 12 wire is less than half the proper size. Also make sure all utilities, like electricity, telephone and cable are grounded at the same point."

  Another important part of the grounding system is the third prong found on many of today's electrical devices. If your home has receptacles with only two slots, consider re-wiring to accommodate the third prong and grounding wire. And using a three-prong adapter on a two-wire circuit does not increase safety "although using a Ground Fault Circuit Interrupter (GFCI) will give some protection on circuits without the third wire," says Allison. "But you must identify the GFCI protected outlets as not being grounded." Also install GFCIs on any outlets in the vicinity of water.

• Fusing. Fuse boxes that use throwaway glass fuses were common before the 1960s. Inadequate capacity caused by today's electronic and appliance load may cause these fuses to blow frequently. To cut down on the aggravation, some homeowners use oversized fuses for replacement, for example, a 30-amp fuse in a 20-amp circuit.

  The oversized fuse allows more electricity to flow through the wire than it's designed to handle. If something connected to the wire shorts, the wire could overheat and cause a fire. If fuses blow frequently, reduce the load and consider upgrading to a breaker panel with more circuits. And of course, never use a penny behind a blown fuse.

• Loose connections. There are literally hundreds of connections in an average wiring system. Loose connections make the electricity work harder to flow across the junction, causing arcing and heat buildup. If there's enough heat, fire could result. "If you feel heat at an electrical device, see charring or smell smoke, contact an electrician," says Allison.

• Aluminum wiring. Some homes that were built, re-wired or had circuits added between 1965 and 1973 could have small gauge aluminum wiring. The problem occurs when the aluminum wire at wire junctions, switches and receptacles corrodes. Large gauge aluminum wire, commonly used between the meter and the main panel, is typically treated with anti-oxidant paste to avoid this problem.

  Over time, corrosion degrades the connection and increases its resistance. The extra resistance creates heat. If the connection gets hot enough, fire results.

  Since there's no practical way to correct connections hidden in walls, under floors or above ceilings, it?s best to replace small gauge aluminum wire.

• Service entrance connections. Have a qualified electrician periodically check and re-tighten the connections inside your home's meter base and service entrance panel. Feel the cover of the service entrance panel. If it's warm, there may be loose connections inside.

• Stretching Outlet Capacity. "If you use adapters that make six outlets out of two or use extension cords as a permanent part of the wiring system, it's time to have a qualified electrician install more outlets," says Allison.

What if you find problems? The best course of action is to call a qualified electrician. Make sure the electrician you hire is licensed and insured. Some electricians even specialize in upgrading or repairing existing homes.