When you’re building or fully renovating a custom home anywhere from Vancouver Island to Halifax, the electrical system is the one thing you only want to do once. Get the wiring right the first time and your house will feel modern for the next thirty years. Get it wrong and you’ll be chasing extension cords, tripping breakers, paying for expensive upgrades, or worse, dealing with insurance headaches after a fire claim.
In Canada especially, our extreme climate, skyrocketing power demands (EVs, heat pumps, induction cooking, saunas, home theatres), and very strict electrical codes make “standard builder wiring” feel like it belongs in the 1990s. That’s why smart owners across Toronto, Calgary, Ottawa, Kelowna, and Halifax are insisting on true custom home and basement wiring packages in 2025.
Here’s absolutely everything you need to know, written the way Canadian contractors and homeowners actually talk about it on job sites and in design centres.
Start with the End in Mind: Service Size Is Everything
Ten years ago, a 200-amp service was considered huge. Today, most new custom homes should be built with 400-amp service right from the start. The math is brutally simple. A single Level-2 EV charger can eat 40 80 amps by itself. Add an electric tankless water heater, a heat pump, an induction range, and a finished basement suite with its own cooking appliances, and you’re easily over 300 amps of calculated demand.
Hydro companies such as BC Hydro to Hydro-Quebec, and Toronto Hydro are now regularly permitting 400 amp residential services, and the additional cost up front is typically only 8000-14000 as opposed to a simple 200 amp connection. Attempts to add upgrades later, after the house is complete and landscaped, can cost between 25,000 and 45,000 and involve the ripping up of driveways or internal walls.
The most intelligent thing to do is to invite a master electrician during your design sessions with your architect and builder. Before the foundation is even poured, a correct CEC Rule 8 load calculation on paper (or using software such as the online calculator provided by ESA in Ontario) will inform you of the exact amount that you require.
Where to Put the Electrical Panels
The last thing that you would want is to have your main electrical panel installed in cold Canadian garages. During winter, the moisture condenses on cold metals and, therefore, the labels become illegible at -30 degC and the breakers may become slow or even frozen. In lieu, nearly all high-end custom homes constructed in 2025 are placing the central 400-amp panel in a dedicated, heated, mechanical room, usually directly adjacent to the furnace and the water heater.
Many of the owners connect a 125- or 200-amp subpanel directly in the mechanical basement. One such decision just makes it infinitely easier and less expensive to add a hot tub, a second EV charger, a generator, or a separate legal second suite in the future.
The Modern Canadian Basement Is Basically a Second House
Basements used to be cold storage and laundry rooms. Now they’re income-generating rental suites in Vancouver and Toronto, $150,000 home theatres in Calgary, or complete in-law apartments for aging parents in Atlantic Canada.
That transformation means basement wiring has to be treated entirely differently than it was even five years ago. A correctly wired modern basement typically includes its own subpanel, dedicated 20-amp circuits for every major room, separate heating circuits for electric in-floor heat (huge in Manitoba and Saskatchewan), a dedicated sump-pump circuit on battery backup, and heavy-up circuits ready for future saunas or indoor EV charging.
Suppose you’re building a legal secondary suite. In that case, most provinces now require a completely separate 100- or 125-amp panel for the suite, fire-rated separation, and interconnected smoke/CO alarms that trigger the whole house. Doing it right the first time avoids the nightmare (and massive cost) of trying to add a second meter or panel once the ceiling is drywalled.
Future-Proofing That Actually Pays Off
The cheapest time to run cable is when the walls are open. Every serious custom build happening right now across Canada in 2025 is pre-wiring for low-voltage and data the same way we used to only worry about power.
That means running Cat6A or better to every bedroom, office, living room, and especially the basement theatre or suite. It means centralized racks in the mechanical room, coaxial cable in case Shaw or Bell still needs it years from now, and most importantly, empty 2-inch conduit runs from basement to attic so you can pull fibre, new Ethernet standards, or solar cables a decade from now without destroying finished ceilings.
Owners who skip this step almost always regret it. Retrofitting structured wiring after the fact easily costs $8,000 $20,000 and leaves you with patches in the drywall forever.
Cold-Climate Details Most Electricians Still Get Wrong
Canadian winters do things to wiring that Florida or California electricians never see. Cables bundled too tightly in insulated attics overheat in summer, even when it’s -20 °C outside, as attic temperatures reach 60 °C. The Canadian Electrical Code forces you to derate ampacity in those conditions, and many crews still forget.
Exterior receptacles must be WR (weather-resistant) type and installed while in use in bubble covers. Underground feeds to detached garages or hot tubs should always be TECK90 armoured cable or RW90 in conduit, never NMWU exposed to sunlight or mechanical damage.
And if you’re in snow country (pretty much everywhere except the BC coast), seriously consider budgeting for snow-melt systems in the driveway and roof de-icing cables. Those systems pull massive current, often 100 150 amps, and need their own subpanel and controls wired during original construction.
Absolute 2025 Pricing Across Canada (No Fluff)
Here’s what owners are actually paying right now, based on quotes from Red Seal master electricians in multiple provinces:
A complete 400-amp service entrance with meter socket, main panel, grounding, and surge protection runs $9,000 $14,000.
Complete smart-home pre-wire (Cat6A + coax + speakers + centralized rack) for a 3,500 5,000 sq ft house is $5,000 $8,500.
Basement rough-in ready for a legal suite, home theatre, gym, and sauna costs between $11,000 and $18,000, depending on the province and complexity.
Running a 60-amp or 100-amp circuit for an EV charger averages $2,000 $3,500.
Whole-home generator ready (22 26 kW automatic standby with transfer switch) adds another $3,500 $5,500 in electrical work alone.
Total premium for a fully future-proofed electrical package vs. basic builder-grade? Usually $32,000 $48,000 on a typical detached custom home. Most of that money comes back on resale, especially in hot markets where buyers now expect 400-amp service and proper data wiring the same way they expect quartz counters.
Permits, Inspections, and Not Getting Screwed
Every province has its own electrical safety authority, and they do not mess around. Ontario’s Electrical Safety Authority, BC’s Technical Safety BC, Alberta’s Safety Codes Council, and Québec’s RBQ all require permits and multiple inspections. Cutting corners with an unlicensed handyman can void your home insurance and make the house impossible to sell later.
Always verify your electrician carries valid liability insurance, WSIB/WCB coverage, and a master certification. Ask to see past custom homes they’ve wired, especially finished basements and smart-home installations.
The Checklist You Hand Your Electrician Before Drywall
Walk the job with your electrician one last time before insulation and make sure every one of these is done:
- 400-amp service and panel in a heated space
- Basement subpanel installed and labelled
- All home runs pulled, appropriately stapled, and clearly labelled at both ends
- Empty 2-inch conduits from the basement to attic
- Whole-home surge protector at the main panel
- AFCI breakers on every 15- and 20-amp circuit (now mandatory almost everywhere in Canada
- GFCI protection in all wet areas, plus unfinished basement spaces
- Hardwired, interconnected smoke and CO alarms with 10-year sealed batteries
- Dedicated 20-amp circuits in every bedroom and living area (no more “one circuit for three bedrooms”)
- Exterior and garage receptacles on separate circuits with weatherproof covers
Do it once, do it right, and your custom Canadian home will still feel cutting-edge in 2050 instead of desperately needing a $50,000 electrical overhaul in 2035.
That’s the real difference between a house and a true custom home in Canada today: wiring that’s planned twenty years ahead instead of twenty years behind.
