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How to Wire a New House for the Next 30 Years: Panel, Circuits, Low Voltage and the Things You Cannot Add Later
During construction Electrical From a builder
How to Wire a New House for the Next 30 Years: Panel, Circuits, Low Voltage and the Things You Cannot Add Later
A wire that costs four dollars before drywall costs four hundred after it. That is the whole lesson. Here is the list we walk through with every client the week before the electrician starts, in the order the regrets usually arrive.
Short version: Plan the electrical for the house you will have in 2040, not the one you move into: a 200 amp panel (or a load-managed 200 with room for an EV, a heat pump and a future suite), an EV charger circuit to the garage, a generator or battery transfer provision, Cat6 home-run to every TV, desk and access point location, conduit from the basement to the attic and to the garage, and camera, doorbell and speaker drops. Ontario work is done by a Licensed Electrical Contractor under the Ontario Electrical Safety Code and inspected by the ESA at rough-in and final. Walk the framed house with the electrician and a roll of blue tape before the rough-in; it is the cheapest hour you will spend on the build.
The panel and the service
Ask for a 200 amp service and panel as the default. A 100 amp panel was fine for a gas-heated house with one car; it is not fine for a heat pump, an induction range, an EV and a hot tub. If the utility service or the budget pushes you to a smaller service, a load management device can run a heat pump and an EV charger on it safely, but you want the panel spaces either way. Put the panel somewhere you can get at it, with 40 or more spaces, and leave a quarter of them empty on move-in day.
Heat pumps change the panel. A cold-climate air-source unit with backup heat is often the biggest load in the house; size the service from the mechanical design, not a rule of thumb. Cold-climate heat pumps explains why the electrical and mechanical designs have to meet before the permit.
Circuits people wish they had run
- EV charger: a dedicated 40 to 60 amp circuit to the garage or parking spot, even if you do not own an EV yet; the conduit is the cheap part.
- Generator or battery: an interlock or transfer switch provision and an exterior inlet, so an outage is an extension cord problem and not a frozen-pipes problem. Power outages in an ICF house covers the heating side.
- Kitchen: more small-appliance circuits than the Code minimum, a dedicated circuit for the fridge, the microwave, the dishwasher, and the island, plus a 40 to 50 amp range circuit even if you are choosing gas today.
- Garage and workshop: 240 volt outlet, a separate 20 amp circuit, and exterior outlets at the front and back of the house on their own circuit.
- Bathrooms: a dedicated 20 amp circuit per bathroom, a heated-floor circuit if there is any chance you will want it.
- Mechanical room: outlets for the HRV, the sump pump on its own circuit with a battery backup, the water treatment, and a future hot water heat pump.
- Exterior: soffit outlets for holiday lights on a switch, outlets at the deck and the shed, and a circuit roughed to where a hot tub might go.
Low voltage: the part most builders skip
Wi-Fi is not a reason to skip wire. A wired access point on each floor, in the ceiling, beats any mesh system, and the TV, the office desk and the game console all work better on a cable. Run:
- Cat6 (not Cat5e) home-run from a central panel to every TV location, every desk, each access point location on each floor, the garage, the mechanical room and the front door. Two runs to the TV and office spots.
- A structured wiring panel in the mechanical room or a closet, with power, where the internet service enters; the provider will thank you.
- RG6 coax to the TV spots if you have any chance of satellite or cable; cheap insurance even in a streaming house.
- Doorbell and camera drops at the front door, the garage, and the back corner; a Cat6 run does all of them with power over ethernet.
- Speaker wire to the rooms where you want music, and to the patio.
- Conduit: a 1 inch or bigger empty conduit from the basement to the attic, and another from the panel area to the garage. Whatever technology shows up in 2035 gets pulled through it.
- Thermostat and HRV control wires to where the thermostats will be, not where the HVAC installer finds it easiest.
Switches, outlets and lights: the walkthrough
The electrician will place outlets to the Code minimum (no point on a wall more than 1.8 m from an outlet, in general) and switches where the plans show them. The plans are rarely where you will stand. So walk the framed house with painter’s tape: mark every switch at the hand you will use, three-way switches at both ends of halls and stairs, outlets behind where the bed and the sofa will actually sit, one in the pantry, one in the closet for the vacuum, one inside the vanity drawer, one on the kitchen island. Lighting and outlet planning before drywall is the room-by-room version with the lighting layers.
What the Code and the ESA require
Electrical work in Ontario is done under the Ontario Electrical Safety Code by a Licensed Electrical Contractor, who files the permit (a notification of work) with the Electrical Safety Authority. The ESA inspects at rough-in, before insulation, and at final. The inspector checks box fill, wire sizes and breaker ratings, GFCI protection at kitchens, bathrooms, outdoors and garages, arc-fault protection on most living-space circuits, tamper-resistant receptacles, smoke and CO alarm wiring and interconnection, bonding and grounding, and the service itself. Smoke and CO alarm rules has that piece in detail. Keep the ESA certificate of inspection; your insurer and your buyer will want it.
In an ICF house
Wiring an ICF wall is different and easier than people expect: the electrician cuts a channel into the interior foam with a hot knife or a router, presses the cable in, and fastens boxes to the plastic webs embedded in the form. Nothing penetrates the concrete. Plan the box locations before the pour anyway, because sleeves through the wall for the service entrance, the EV conduit to a detached garage, and exterior lights all go in while the forms are open. What ICF is covers the wall; the electrician who has done one before will not need the lecture.
Related guides on this site
Sources and further reading
Questions people ask
What size electrical panel does a new house need in Ontario?
A 200 amp service is the sensible default for a new house, especially with a heat pump, an induction range or an EV. Size it from the mechanical design and the loads you expect in ten years, and leave spare breaker spaces.
Should I run network cable in a new house or just use Wi-Fi?
Run Cat6 to every TV, desk and a ceiling access point location on each floor, plus conduit from basement to attic. Wired access points make Wi-Fi work; wired TVs and desks work regardless. Before drywall it costs a few hundred dollars.
Who can do electrical work on a new house in Ontario?
A Licensed Electrical Contractor, under the Ontario Electrical Safety Code. They file the work with the Electrical Safety Authority, which inspects at rough-in and at final and issues the certificate.
How do you wire an ICF house?
Channels are cut into the interior foam for the cable, and boxes fasten to the plastic webs in the form. Sleeves for the service entrance and any conduit through the wall go in before the concrete is poured.
Building in Simcoe County or on Georgian Bay?
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Reviewed and updated October 2026. Costs are Ontario ranges, not quotes; code references are to the Ontario Building Code in force at that date.
It really helped when you talked about the importance of considering our future needs when wiring our new home. Recently, my wife and I started to work on our home’s construction project. We’re at the utility part, so we’ll be sure to read your piece thoroughly before any decision. Thanks for the tips on home electrical systems.