Understanding Knob & Tube and Aluminum Wiring - February 11th 2011


Understanding Knob & Tube and Aluminum Wiring


Since the convenience of electricity was first brought in to our homes in the early 1900's, various electrical wiring types have evolved over time and all if installed and maintained correctly can be safe. However, if not installed or maintained correctly, each has potential risks. Shell Busey's Home Service Referral Network receives inquiries from a growing number of people in older homes where insurance policies are being cancelled at renewal or individuals are unable to obtain new coverage because of electrical wiring. If you're one of the thousands of homeowners living with Knob and Tube and Aluminum Wiring, understanding the way your house is wired can help you weigh your options to make informed decisions about upgrading the electrical system for insurance coverage.

Some wiring (e.g., knob-and-tube, aluminum) can increase the chance of a fire, especially if the wiring has deteriorated or been damaged during renovations. Some insurance companies want a guarantee that a home does not have this wiring, some may give you time to have it removed, while others might request an inspection to ensure its safety.


Is It Safe?

Many industry experts including, Hydro authorities and several licensed electricians, confirm that 60-amp service and both knob-and-tube and aluminum wiring are not necessarily problems in themselves. They recommend inspection to ensure that the wiring is safe and adequate for the usage of the Household.


"Knob & Tube" Wiring

Knob & tube wiring is a type of wiring which was in common use until the 1940's. More than 1.5 million homes across Canada were built with knob and tube wiring. It was an early form of electrical wiring that was used up to 1945. So, many homes still have it but is now considered too risky and dangerous to be insurable, and for your own safety, and home resale value it should be replaced with copper wiring.

Knob & tube wiring is comprised of insulated wires clamped on two-piece porcelain knobs; positive and negative are carried separately. Hollow porcelain tubes carry the wires, through beams and other combustible materials. Modern electrical codes do not permit this type of wiring. It can present a hazard if tampered with, particularly at unenclosed, soldered-and-taped junctions. The unsheathed insulation is subject to deterioration, particularly where it is exposed, that is, not enclosed in a wall or ceiling. Worn insulation, of course, presents a shock hazard

The ESA's (Electrical Safety Authority) recommendation to insurance companies on knob and tube wiring is that they ask for inspections to make sure the wiring is safe. It does not recommend denying someone insurance simply because they have some knob and tube wiring, although individual insurance firms can refuse coverage for homes with knob and tube wiring as they see fit.


What You Can Do

The first thing to determine is the safety of your system. Even if your system is determined safe, consider upgrading at least parts of it. The areas of a knob and tube installation that are most vulnerable to mechanical damage and trouble are also those areas that are exposed and easiest to change. An electrician can advise you on various upgrade options but don't attempt an upgrade yourself.

If your existing knob and tube system is certified safe, and you'd like to seek coverage for your home as it is, then call the Insurance Bureau of Canada.


About Aluminum Wiring

Houses with aluminum wiring are generally safe and do not cause concern even on the insurance level. Al Schill of Schill Robinson Insurance identified that your homes electrical panel is your main concern. If your home still has an older fuse type panel, it could be a major insurance, and safety risk.

Fuse panels can be upgraded to breaker panels quite easily, and at a lower cost than rewiring an entire home. The main areas of concern with aluminum wiring are your homes connectors and receptacles. When aluminum wiring was first being installed, the same receptacles and connectors were used as for copper wire, but this does not work. The connections can become loose and overheat, possibly causing a fire.

Brent Murphy of BPM Electric states that receptacles can be retied with copper tails, which is roughly a 1-2 day task to refit an entire home. This increases your homes safety and brings it up to today's code standards.


If you have any further questions on home insurance or electrical hazards in your home, please call Shell Busey's Home Services Referral Network, at 604 542 2236, or toll free 1 888 266 8806 throughout western Canada, and we'll put you in touch with the right people.