Knob and Tube Wiring: 3 Myths and Misconceptions

In Peterborough, Ontario, many older homes still feature knob and tube wiring, a system that was commonly used in houses built before the 1950s. While it once served its purpose, modern electrical demands far exceed what this wiring can handle. Unfortunately, several myths surround knob and tube wiring, leading some homeowners to delay necessary upgrades. Here's a look at the most common misconceptions.

Myth 1:  Knob and Tube Wiring is Safe if it's Working 

Many believe that as long as the knob and tube wiring is functioning, it's safe. However, this wiring lacks grounding, which means it poses a serious fire hazard, especially when overloaded with modern electrical demands. According to Peterborough's local electricians, the risk is higher in homes with added insulation, as heat can't dissipate properly, increasing the likelihood of electrical fires.

Myth 2:  You Don’t Need to Replace Knob and Tube Wiring Unless It Fails

While it might seem economical to leave old wiring in place, the truth is that most insurance companies in Ontario require knob and tube replacement. Many insurers in Peterborough won’t offer coverage for homes with this outdated wiring, or they may charge significantly higher premiums until the wiring is upgraded.  So if you're taking over an older home in Peterborough, whether it's to live in yourself or as an investment property, it would be smart to consider a whole house rewiring.

Myth 3:  Knob and Tube Wiring is Compatible with Modern Appliances

Modern appliances demand far more power than the electrical systems of the early 20th century. Knob and tube wiring was never designed to support today's electrical load, including refrigerators, air conditioners, and computers. Attempting to use modern appliances on this system increases the risk of overloading circuits and causing electrical fires. 

Why Upgrading is Essential  

For Peterborough residents, upgrading knob and tube wiring is not just about safety but also about meeting modern electrical standards. With nearly 20% of the housing stock in Peterborough dating back to pre-1960, many homes are likely to have this outdated wiring system. Replacing it improves safety, increases the home’s electrical capacity, and makes homes more attractive to buyers. Additionally, the cost of replacing knob and tube wiring can often be offset by the reduction in insurance premiums and increased property value.


While some myths persist about knob and tube wiring, it’s essential to understand the real risks associated with it. For homeowners, upgrading this outdated system is crucial for both safety and compliance with insurance requirements. Don’t wait for a problem to occur—schedule an inspection with a licensed electrician in Peterborough today.