How Long Does Wiring in a House Last?

The lifetime of the wiring in a house is determined not so much by material deterioration, but more by the fact that electrical systems in many older dwellings are obsolete. Some heavily used components of an electrical system or those exposed to the weather may deteriorate more quickly than an entire system.

Knob and Tube

Builders installed knob and tube wiring in pre-World War II houses. This system consists of unsheathed positive and negative wires coated with a cloth and rubber compound. Knob and tube wiring is especially unsafe in exposed areas such as cellars and should be replaced with modern cable. In fact, modern building codes prohibit such wiring. Furthermore, insurance companies will not underwrite policies for houses outfitted with this wiring.

Fuse Boxes

Another dated electrical system found even in homes built after World War II are fuse boxes. Whenever a fuse blows, homeowners may be tempted to upgrade or replace low amperage ones with higher amperage ones. This will not solve the problem of blown fuses and could cause a fire because of overheated wires.

Breaker Boxes

Better Homes and Gardens experts recommend that you replace fuse boxes with the safer breaker box. Homeowners are unable to undermine the shut-off safety feature of breakers. However, loose connections in the breaker box could cause a short and even spark a fire. The lifetime of breaker boxes is indefinite, but breaker boxes should be serviced if they emit humming noises.

Circuits

Often, older homes do not have enough circuits. Modern kitchens are equipped with conveniences such as garbage disposals, dishwashers and microwave ovens that draw a considerable amount of electricity. One 15-amp circuit is insufficient for this kind of electrical flow. The solution is to add circuits to high-draw rooms such as kitchens.

Ungrounded Wiring

Better Homes and Gardens also emphasizes the need to replace ungrounded wiring. At the least, some grounded cable should be installed in order to outfit a house with 240 volt outlets for heavy-duty appliances.

Switches and Outlets

Constant plugging and unplugging of appliances can cause a receptacle to lose its ability to grip and hold a plug in the outlet. Likewise, the constant throwing of light switches can cause wear and tear. Depending on usage, likely you will need to replace switches and outlets long before other parts of an electrical system wear out.