Knob and Tube Wiring in Newmarket: Assessment, Replacement and Removal
KV Bear Electrical is a licensed electrical contractor (ECRA/ESA 7014730) based in Oshawa that does residential work in Newmarket. Here's what our knob & tube wiring service looks like for a home in Newmarket.
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Knob and tube wiring in Newmarket tends to come to light at an awkward moment: an insurance renewal, a home inspection during a sale, or plans to finish the basement of an older house. ESA dates the system to homes built from the early 1900s to the 1940s, so it turns up in houses from that era and in the original sections of houses that were later added onto. After decades of piecemeal updates, the owner rarely knows how much of it still carries power.
Answering that question is the first job for a knob and tube electrician in Newmarket, and the answer sets the size of the project. Replacing a handful of branch circuits stays inside the house and is filed with ESA. Taking out an old fuse box at the same time pulls in NT Power, the town's own electricity distributor, along with its meter base rules. A house in the Lower Main Street South heritage district, or one with a basement unit the owner wants registered, adds a Town step as well.
What Newmarket Homeowners Should Know
For services supplied underground, NT Power has required a 200 amp meter base since January 1, 2010 for service upgrades up to 200 A, panel changes, service entrance cable relocations, recessed meter base upgrades and any other condition that requires the customer's service to be disconnected. On an overhead service of up to 100 A, a standard rectangular meter base is acceptable.
Source: Contractor Information, NT Power (ntpower.ca)NT Power's Conditions of Service (effective March 14, 2022) say a customer who needs the service isolated and re-energized for maintenance or electrical upgrade work must contact NT Power in writing to make the arrangements. NT Power connects a customer's service to its distribution system only after it receives written Connection Authorization from ESA.
Source: Conditions of Service (effective March 14, 2022), NT Power (ntpower.ca)Under the same Conditions of Service, when a service has been disconnected for six months or longer, NT Power may require the conditions of a new service to be met on a reconnection request. The customer then needs an ESA inspection of the installation and a Connection Authorization before NT Power reconnects.
Source: Conditions of Service (effective March 14, 2022), NT Power (ntpower.ca)NT Power's service request page rules out recessing, embedding or adding architectural detailing to the meter base or its conduit.
Source: Service Requests, NT Power (ntpower.ca)Lower Main Street South is the Town of Newmarket's only heritage conservation district. It covers 72 properties under Part V of the Ontario Heritage Act, and the Town requires a heritage permit for alterations to, or demolition of, a property inside it.
Source: Heritage Conservation Planning, Town of Newmarket (newmarket.ca)Newmarket's heritage district permit application tells owners to reach out to the Town's Cultural Heritage Planner before applying, says a pre-consultation meeting may be required, and notes that a building permit, planning approvals or a sign permit may also be needed.
Source: Heritage District Permit Application, Town of Newmarket (newmarket.ca)Newmarket's registration checklist for an additional residential unit includes an ESA compliance report on both the upper and lower units, no more than six months old when the application goes in. A unit built before 1995 also needs a letter from Central York Fire Services confirming Fire Code compliance, under the same six-month limit.
Source: Register Your Additional Residential Unit, Town of Newmarket (newmarket.ca)Central York Fire Services tells residents to always use a licensed electrical contractor to inspect and install additional circuits and outlets and to complete electrical repairs. It adds that extension cords are not designed for long-term use or to replace permanent wiring.
Source: Residential Safety Tips, Central York Fire Services (cyfs.ca)ESA's Flash 25-05-FL (May 2025) lets hidden knob and tube on general lighting and receptacle circuits stay in service if it is protected at 15 A by a fuse or breaker, no added outlets overload the circuit, and the conductors that can be seen are sound. If such a circuit needs a three-prong receptacle, ESA says only a GFCI receptacle should be used.
Source: Flash 25-05-FL: Knob and tube wiring in residential installations, Electrical Safety Authority (esasafe.com)ESA's knob and tube page says some insurers may require the wiring to be replaced before they provide coverage. It recommends an electrical assessment by a Licensed Electrical Contractor, which differs from a home inspection because it focuses only on the electrical.
Source: Knob and Tube Wiring, Electrical Safety Authority (esasafe.com)
Facts checked October 26, 2026.
Knob and Tube Inspection in Newmarket: Mapping Every Old Circuit
The assessment begins at the fuse box or panel and works outward. Circuits are switched off one at a time, the outlets and lights that go dead are recorded, and the wiring is examined wherever it can be reached: along the basement joists, in the attic, and behind a sample of switch and outlet covers. ESA stresses that an assessment by a Licensed Electrical Contractor differs from a home inspection because it deals with the electrical system alone. That narrower focus is what makes it possible to say which runs are knob and tube, which are later cable, and where the two have been spliced together.
Each finding is then measured against ESA's Flash 25-05-FL. Concealed knob and tube can keep working if it is fused or breakered at 15 A, has not been overloaded with added outlets, and looks sound wherever it is exposed. Any run that misses one of those tests goes on the replacement list. ESA also calls for replacing conductors that show mechanical abuse, deterioration, poor connections, overheating or alterations that overload them.
Outlets get a line in the report too. Central York Fire Services, the joint fire department for Newmarket and Aurora, warns that extension cords are not built for long-term use or to stand in for permanent wiring. A room that only works with cords and power bars needs a new grounded circuit. Where a circuit stays on knob and tube and a three-prong receptacle is wanted, ESA permits only a GFCI receptacle.
Knob and Tube Removal in Newmarket When the Fuse Box Goes Too
Plenty of houses that still have knob and tube also still have the fuse box it was wired into, and replacing that box means cutting the supply. In Newmarket, that is arranged with NT Power. Its Conditions of Service ask customers to request an isolation for maintenance or upgrade work in writing, and power is restored only after NT Power has ESA's written Connection Authorization for the new equipment.
NT Power's contractor rules also affect the parts list. On a house fed by an underground service, a panel change or any other work that needs the service disconnected calls for a 200 amp meter base. On an overhead service of up to 100 A, a standard rectangular meter base is still acceptable. Confirm which kind of supply the house has before comparing quotes, because a new meter base adds material and outside work that a panel swap on its own would not.
Homes in the Lower Main Street South district add a heritage step. Alterations to any of the district's 72 properties need a heritage permit, and the Town's application form asks owners to talk to its Cultural Heritage Planner before they apply. Describe the whole electrical scope in that conversation, and flag anything that will be visible outside, such as a new meter base, mast or conduit. Disguising that equipment to suit the facade is not an option, since NT Power does not allow the meter base or its conduit to be recessed, embedded or architecturally detailed.
House Rewiring in Newmarket: Rough-In Inspections and Second Units
Knob and tube wiring replacement in Newmarket follows the same sequence as any house rewiring. The ESA notification goes in first. New grounded copper circuits are then run from the panel to each room, fished through finished walls from the basement and attic wherever the framing allows, and every abandoned conductor is disconnected so it cannot be energized again. ESA's rough-in rule controls the pace from there: no wiring may be concealed by insulation or by floor, wall or ceiling materials until an inspector authorizes it. Book the inspection before the plaster repairs, not after them.
A second unit changes the order of work. Registering an additional residential unit in Newmarket takes an ESA compliance report on both units, dated within six months of the application. If the upstairs is still on knob and tube, settle the replacement scope before booking the ESA visit for that report, so the report describes the finished wiring and is still current when the paperwork goes to the Town.
When ESA accepts the installation, it issues the ESA Certificate of Acceptance to whoever filed the notification, usually your contractor. Ask for a copy. ESA describes the certificate as an important document for insurance and resale, so send it to any insurer that made replacing the knob and tube a condition of coverage.
Knob & Tube Wiring in Newmarket: Common Questions
Does NT Power have to be involved when knob and tube comes out of a Newmarket house?
Only if the supply has to be cut. New circuits fed from an existing breaker panel are an electrical-only job: the Town does not regulate electrical installations and asks for no building permit for that kind of work, so the filing goes to ESA. Replacing a fuse box or panel is different. NT Power arranges the isolation on a written request, reconnects once it holds ESA's Connection Authorization, and requires a 200 amp meter base on an underground supply.
Should I speak to the Town before rewiring a house in Newmarket's heritage district?
Yes. The Town requires a heritage permit for alterations to properties in the Lower Main Street South district, and its permit form asks owners to contact the Cultural Heritage Planner first; a pre-consultation meeting may be required. Bring the full electrical plan and point out anything that will show on the outside, such as a new meter base, mast or conduit, so the planner can say what needs a permit. A building permit or other approvals may be needed alongside it.
Is partial knob and tube replacement allowed in a Newmarket home?
The electrical code allows it. ESA's Flash 25-05-FL lets concealed knob and tube stay in service on a 15 A fuse or breaker when no added outlets overload it and the visible conductors are in good shape, so replacing only the circuits that fail those tests can be compliant. Your insurer may ask for more. ESA notes that some insurers want the wiring replaced before they provide coverage, so get the insurer's conditions in writing before you settle on a partial scope.
What happens if a Newmarket house is left disconnected for months during a rewire?
NT Power's Conditions of Service let it treat a service that has been off for six months or longer as a new service when reconnection is requested. The house would then need an ESA inspection and a Connection Authorization before NT Power restores power. If a gut renovation will leave the house empty, ask for the panel change to be scheduled late in the project so the disconnection stays well short of six months.
How is the price of knob and tube wiring replacement in Newmarket worked out?
It is based on the assessment. KV Bear Electrical publishes a range of $8,000 to $20,000 or more for full knob and tube removal in a typical Ontario home (as of October 2026). The quote narrows that down by counting the circuits still on knob and tube, the finished walls and ceilings the new cable has to pass through, and any fuse box, panel or meter base change. Houses with only partial knob and tube tend to land toward the lower end. To book an assessment at your Newmarket house, call 905-999-5048 or request a quote.
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