Knob-and-tube wiring in an older home

Identify extent, condition, alterations and insurance constraints without treating Ontario rules as Canada-wide.

VERT / GREEN = documenter/entretenir · JAUNE / YELLOW = mesurer/vérifier · ROUGE / RED = arrêter et faire sécuriser/valider.

Brittle/overheated/altered conductors
Stop DIY alterations and have an authorized electrician inspect. Insulation added around wiring
Verify compatibility before continuing insulation work. Insurance/jurisdiction not checked
Confirm local rules and insurer requirements; do not generalize Ontario rules. Circuit map available
Document visible portions and wiring generations.

What the professional checks

Inspect condition, loading and alterations
Define retain/replace strategy for the jurisdiction

Official sources

ESA Ontario — knob-and-tube

Checked: 2026-08-22

V15

Remaining system checks not to miss

V15 covers issues that can block a project, cause a loss or become expensive once concealed.

Before closing wallsOld electrical systemPost-renovation commissioningCodes + climate by province