The relatively new home, or the one with an updated electrical system, will allow for safe and reliable use of the latest electric "toys". But, houses built under older codes often suffer from outdated electrical systems not designed for today's uses.
These older systems typically have a fuse box with a 60 or 100 amp capacity, and individual circuit wires insulated with ceramic tubes and spindle-like knobs ("tube and knob wiring". These systems were designed primarily to be used for simple lighting circuits. The assumption was that most rooms would have a single overhead light and possibly one floor lamp. Such a wiring system, if well maintained, will continue to serve for its original purpose--namely lighting. But the designer of this system could not envision the proliferation of electric appliances.
Our microwaves, video recorders and other electronic toys are items that, in combination, can often cause an overload. In addition, the old wiring systems were not designed to accommodate the many portable heaters on the market today.
Fire departments list electrical problems as one of the major causes of fires in the home.
Typically, such a fire starts with the homeowner replacing the original 15 amp fuses with, for example, a 30 amp fuse, in the mistaken belief that a larger fuse is better because it blows less often. The homeowner now has inadvertently destroyed the very system designed to protect the home.
The danger lies in the overheating of the wire at its weakest link. An example of this can be seen in attaching a new, higher capacity wire to an old tube and knob circuit. If such an installation is over-fused and overloaded, it is possible for the old tube and knob wiring inside the wall or crawl space to overheat and possibly start a fire. The fire can start without blowing the oversized fuse or any other sign of a problem in the new segment of wiring.
An inspector or qualified electrician may be needed to determine whether a home has an electrical system adequate for today's needs.
The electrical system that will accommodate most of today's electric appliances is usually characterized by the following:
However, a little knowledge can be dangerous: just because the receptacle is of the newer 3 pronged variety does not mean that it was wired correctly, the same can be true about the GFIs and AFIs.
Most older home electrical systems can be upgraded into safe and fully functional systems without a complete re-wiring of the home. Some of the original wiring - even some of the old "tube and knob" - may be safely used for lighting circuits and other low amperage utility circuits. The "87 gig drive" needs a newer grounded circuit, but the light and table radio next to the computer will work fine in a properly functioning 1910 circuit.
So, if you get a bid from an electrician for a re-wiring of the house, here are a few questions to ask:
A note about electricians and other specialty contractors: Some electricians, as well as some roofers, plumbers etc., suffer from the "specialist disease". They are expert in their area of work, but may not be thinking about related items and issues. For example, how to reduce electrical capacity requirements by using natural gas, or how to reduce the need and frequency of bathroom re-painting by installing a better quality fan.
Bathroom accessories; i.e., electric toothbrush, hair dryer, electric shaver: Use a circuit protected with a Ground Fault Interrupter (GFI). Note: Most standard bathroom circuits are designed for hair dryers using no more than 1000 watts. Check the label on your hair dryer, it may be too strong for a "normal" bathroom circuit.
Microwave ovens: A separate 20 amp "dedicated" circuit on its own fuse or circuit breaker.
Dishwasher: Needs a separate 20 amp "dedicated" circuit.
Larger vacuum cleaners and irons: Plug directly into a 20 amp receptacle--usually found in kitchen and utility rooms.
TV, stereo, VCR, audio tape system: Check the wattage rating on each unit and limit load to 500 watts on a single room circuit. Add a separate circuit if necessary.
Electric blankets: Plug directly into an adequate receptacle with a 15 or 20 amp fuse or circuit breaker.
Personal computer system: A separate "dedicated" circuit on its own fuse or circuit breaker.
Portable electric space heater: Plug directly into a 3-pronged, grounded receptacle with a 15 or 20 amp fuse or circuit breaker. (1000 watt limit on any 15 amp circuit. 1500 watt limit on any 20 amp circuit.)
Outdoor equipment: Ground fault interrupter (GFI).
Home workshop tools: Purchase "double insulated" power tools.
Portable hot tub or spa: Needs a "dedicated" circuit with a GFI circuit breaker. Requires a 125 amp, or larger, electrical panel.
Kiln or arc welder: 220 volt circuit which may require a 200 amp, or larger, electrical panel.
Many homeowners like to do their own electrical work. Unfortunately, much of the electrical work done by nonprofessionals does not meet the electrical code and is dangerous. Poorly installed panels and wiring can cause home fires.
The homeowner who decides to do his or her own electrical work should keep in mind the following guidelines: