Is it worth upgrading from 100 amp to 400 amp service for a large home with an EV charger, hot tub, and workshop?

For a large home with an EV charger, hot tub, and workshop, jumping straight to 400A service is worth serious consideration — but it's not automatically the right answer for every home. Most GTA homeowners in this situation land somewhere between 200A and 400A depending on their actual load calculation, and a licensed electrician needs to run the numbers before you commit to either.

Understanding the Load Math

The case for 400A starts with adding up what you're actually running. A Level 2 EV charger draws 40-48A continuously on a dedicated 50A circuit. A hot tub typically pulls 40-60A on its own dedicated 240V circuit. A serious workshop with a table saw, dust collector, air compressor, and welder can easily consume another 60-100A when tools are running simultaneously. Add your home's baseline — central AC (20-40A), electric range (40-50A), electric dryer (30A), water heater, and general lighting and receptacle circuits — and you can see how a 200A panel gets crowded fast.

The critical concept here is demand factor — not everything runs at full load simultaneously. A licensed electrician performs a load calculation following the Ontario Electrical Safety Code to determine your actual peak demand, not just the sum of every circuit's maximum rating. Many large homes with this combination of loads land in the 150-180A actual demand range, which technically fits within 200A service. The question is whether you want headroom for future additions, or whether you're already at the edge.

400A service makes the most sense when your home is large (2,500+ sq ft), fully electric (no gas range, gas dryer, or gas water heater — all electric loads), you're running a serious workshop with heavy three-phase-equivalent single-phase tools, you're planning to add a second EV in the next few years, or you have electric in-floor heating or a large pool pump in addition to the hot tub. In these scenarios, 200A service will leave you with chronic nuisance tripping and no room to grow.

What 400A Service Actually Involves

A 400A residential service in the GTA is not simply a bigger panel — it's a fundamentally different infrastructure upgrade. You'll need a 400A meter base (coordinated with Toronto Hydro), a larger service entrance cable from the weatherhead to the meter, and typically either a single 400A main panel or a 400A meter main feeding two 200A sub-panels (one for the house, one for the workshop/garage). The two-panel approach is common and practical — it gives you dedicated capacity for each zone of your home.

Toronto Hydro must approve and coordinate the service upgrade, which adds time and a utility fee to the project. Your electrician handles the ESA permit and all work from the meter base inward; Toronto Hydro handles the service drop from the street. Expect the utility coordination to add 2-6 weeks to your project timeline, particularly in spring and fall when upgrade demand peaks.

GTA Cost Reality

A 200A service upgrade in the GTA runs $3,500-$5,000 when it includes the meter base and Toronto Hydro coordination. A 400A service upgrade is a more substantial investment — $6,000-$12,000 depending on whether you're running two sub-panels, how far the service entrance cable needs to travel, and whether your weatherhead and exterior service entrance components need replacement (common on homes built before 1990). Add the EV charger circuit ($1,500-$3,000), hot tub connection ($800-$1,500 for the dedicated circuit and disconnect), and workshop sub-panel ($1,200-$2,500) and you're looking at a total project in the $10,000-$18,000 range for the full electrical infrastructure upgrade.

Practical Advice

Have an electrician perform a proper load calculation before deciding between 200A and 400A. If the calculation shows you're comfortable at 200A with reasonable headroom, the upgrade cost difference may not be justified. If you're already planning a second EV, have an all-electric home, or your workshop includes equipment like a large air compressor or MIG welder, the 400A investment pays for itself in avoided future upgrade costs and the peace of mind of never tripping a main breaker.

One more GTA-specific consideration: Toronto's ice storm history makes generator preparedness relevant for a home with this level of electrical investment. A 400A service with a properly installed automatic transfer switch and standby generator protects everything you've built — including the EV charger, workshop tools, and hot tub systems — during multi-day outages.

Get matched with a licensed electrician through Toronto Electrical Repair for a free load calculation and estimate — this is exactly the kind of project where getting the service size right from the start saves you from a costly redo in five years.