|“Knob and tube” (K&T) wiring|
• Two separate conductors held in place by ceramic knobs.
Ungrounded twin-conductor cable, called “NMD-1”
• NMD-1 contained no ground wire (Ground wire was not required in code until 1962).
|NMD 3 & 6|
• The predominant cables used during this period.
• The insulation temperature ratings of these cables are 60°C and 75°C respectively.
• Worked fine for most circuits, but not for recessed ceiling lighting (pot lights).
|Aluminum wiring (Al)|
• Installed in the vast majority of houses as an inexpensive
solution to escalated price of copper.
• Can be extremely dangerous if not checked and maintained regularly by a licensed electrical contractor.
• Homes wired with Al, are 55 times more likely to lead to structure fires than copper wired homes.
|Modern cable (NMD 7 & NMD-90)|
• Modern house wire. Jacket of PVC.
• Approved for use with ceiling fixtures. Rated at 90°C.
The Canadian Electrical Code, CE code is a standard published by the Canadian Standards Association pertaining to the installation and maintenance of electrical equipment in Canada.
The first edition of the Canadian Electrical Code was published in 1927. The current (23rd) edition was published in 2015. Code revisions are now scheduled on a three-year cycle.The Canadian Electrical Code serves as the basis for wiring regulations across Canada. Generally, legislation adopts the code by reference, usually with a schedule of changes that amend the code for local conditions.
Since the introduction of electricity in homes, circa. 1910, various electrical wiring types have evolved. The primary types can be loosely grouped into five different categories. All wiring types if installed and maintained correctly can be safe. However, if not installed or maintained correctly, each has potential risks.