100-Amp vs. 200-Amp Electrical Service: Ottawa Homeowner Guide

Before paying for a 200-amp electrical service upgrade, find out whether your Ottawa-area home actually needs more capacity. A full breaker panel, an EV charger, or plans for a heat pump do not automatically mean a 100-amp service must be replaced. The correct decision depends on a qualified assessment of your existing installation, a code-compliant electrical load calculation, the proposed new loads and your electricity distributor's requirements.

The short version: Ask an Ontario Licensed Electrical Contractor (LEC) to confirm the actual service rating and calculate demand for your current and planned equipment. Distinguish a panel replacement from an increase in incoming service capacity. If you need more capacity, coordinate an ESA electrical notification and a utility service-upgrade request before scheduling the disconnect, inspection and reconnection. Start with Hydro Ottawa's electrical service request instructions if that utility appears on your bill.

Scope and date: Reviewed October 16, 2026. This guide covers typical residential 120/240-volt service questions in Ottawa and nearby Ontario communities. It is not an electrical load calculation or site-specific design. Requirements, costs and scheduling vary by utility and property.

1. What is the difference between 100-amp and 200-amp service?

Amperage describes the rated current of an electrical service. A typical residential 120/240-volt, single-phase service supplies both 120-volt circuits and 240-volt loads. A 200-amp service can accommodate a larger calculated load than a 100-amp service when the entire service installation is properly rated and approved.

Important: The kVA figures are arithmetic illustrations, not permitted load calculations or promises that all that current can be continuously used. Applicable code rules, the mix of loads, equipment ratings and utility conditions control the design. Have an LEC document the calculation; do not determine safe loading by adding breaker-handle numbers or relying solely on the size printed on a replacement panel.

2. Panel upgrade, service upgrade or extra circuit: which job do you need?

Homeowners and some advertisements use “panel upgrade” and “service upgrade” interchangeably. They are different scopes. A new 200-amp-rated panel does not by itself change a 100-amp service into a 200-amp service.

A full panel can be a space problem, a capacity problem, both, or neither. An LEC can explain whether code-compliant circuit rearrangement, a new panel, a subpanel, load management or a service upgrade is appropriate. A damaged or unsafe panel may require repair regardless of calculated amperage.

For Hydro Ottawa-served homes, the utility's published ownership guidance identifies items such as the mast, meter base and wires from the meter base to the panel as homeowner responsibilities on typical overhead services, while the utility is responsible for the pole-to-home wires. Confirm the actual ownership boundaries with your distributor; never work on or near energized service equipment yourself. Hydro Ottawa explains typical service responsibilities.

3. When might an Ottawa home genuinely need 200 amps?

The trigger is a calculated demand or another actual system requirement, not simply the presence of one appliance. Ask for a written assessment when you plan several large loads, change heating sources or expand the dwelling.

An EV charger is not an automatic 200-amp mandate. ESA says the additional EV charging load must be assessed and the work requires an electrical notification; Hydro One says a 100-amp home may need upgrading. Some projects can be designed around a smaller charger setting or an approved management arrangement, but feasibility must be determined by the LEC for that home. See ESA's EV guidance and Hydro One's electrical-service discussion.

4. How do you assess a home without guessing?

Start with the facts about the house. Your electricity bill tells you which utility supplies the account; it does not establish the physical rating of the service. An old panel label can also be misleading if equipment has been changed over the years.

A useful contractor assessment should document:

1. Existing service and main disconnect rating. Identify what is actually installed, not merely the breaker count.
2. Condition and ratings of the equipment. Look at the panel, service entrance, meter base, grounding/bonding, and any known deficiencies without the homeowner opening energized compartments.
3. Current fixed loads. Space heating, water heating, range, dryer, air conditioning, pumps and other equipment.
4. Future loads. EV charging, heat pump, secondary suite, shop, hot tub or other changes you realistically expect.
5. Demand/load calculation. Ask for the applicable Ontario Electrical Safety Code calculation and an explanation of any diversity or management provisions.
6. Distributor constraints. Confirm whether the utility will approve the planned service size and whether poles, lines, transformer capacity or underground works affect the design.

Photographs: You can take a photo of the closed panel door, visible labelling and accessible exterior service equipment from a safe location. Do not remove the dead front, open sealed compartments, touch exposed conductors or approach damaged utility lines to get better pictures.

5. Hydro Ottawa, Hydro One and rural property differences

The correct utility is the one serving the specific electrical account, not necessarily the one that covers most of the city or the nearest municipality. Some Ottawa-area homes are supplied by Hydro Ottawa, others by Hydro One, and nearby municipalities can have different distributors.

Hydro Ottawa says to submit a service request three to four weeks before work, expects to contact customers within 10 business days, and provides a customer layout setting out work and estimated utility costs. Its current page also states one free customer layout is available per property in a rolling 12-month period, with qualifications and extra charges possible. These are guidance figures, not a guarantee that service will be upgraded or reconnected within four weeks. Hydro Ottawa service requests.

Hydro One's service process also involves assessing the connection and coordinating required electrical authorization before connection. Its published metering guide advises customers to initiate upgrade discussions early in project planning. Hydro One builders and contractors · Retail metering standards (PDF).

Rural properties: A long overhead service, private pole line, buried conductor, long trench, detached garage, well pump or heat-pump backup load can materially change both the design and the cost. Verify equipment ownership and utility requirements rather than assuming an urban 100A-to-200A quote will apply in Carp, rural Ottawa, Beckwith, Mississippi Mills or Carleton Place.

6. How much does a 100A-to-200A service upgrade cost in Ottawa in 2026?

There is no verified, single Ottawa-wide installed price covering every service upgrade. The scope may range from a straightforward overhead service change to underground reconstruction requiring substantial utility and site work.

For orientation only, one Ottawa contractor advertises a $3,000–$6,000 CAD range for a typical 100A-to-200A service upgrade. That is a commercial advertisement from one provider, not an independently verified average, a municipal fee schedule or a quote for your home. A site-specific price can be lower or substantially higher. See the contractor's advertised example.

A written estimate is much more useful when it separates the real cost components:

ESA reference fee: The 2026 ESA Wiring Fee Guide, Section 4.3.1, lists $86 for the contractor for certain new-service, service-change, repair or panel-change notifications for existing residential structures ($212 non-contractor). The guide flags certain fees with an asterisk and notes that other wiring or additional inspection visits can affect the charge. This is not the installed price, not a quote from ESA for your full project, and not necessarily the only ESA fee involved. Ask the contractor for the exact fee classification.

Hydro Ottawa separately supplies a customer layout with applicable utility costs; don't assume those charges equal the ESA fee or are already included in an electrician's advertised package. Hydro Ottawa service requests.

7. Electrical permits, inspections and reconnection

Ontario requires electrical notifications for almost all installation work. If you hire a contractor, use an ECRA/ESA Licensed Electrical Contractor and verify the business licence in ESA's directory. A person's trade certificate or Master Electrician status is not, by itself, a licence for the business to contract directly with homeowners. ESA hiring guidance.

ESA specifically identifies service upgrades, replacement and relocation as work requiring utility disconnection and a service inspection before power is restored. The contractor and utility need to coordinate this properly. Do not assume that passing a general final inspection later can replace the required service-stage authorization. ESA notifications and inspections.

Ask the contractor to confirm:

1. Who files the ESA notification before work starts?
2. Who submits the service request to your electricity distributor?
3. Which equipment is homeowner-owned and which is utility-owned?
4. When will the outage, ESA service review and utility reconnection occur?
5. Is any additional rough-in or final inspection required for accompanying branch-circuit work?
6. What happens if a defect is found or reconnection cannot occur on the planned day?
7. How will you receive the final ESA Certificate of Acceptance and project records?

ESA explains that the Certificate of Acceptance is issued to the notification holder after work has been reviewed and accepted. If the contractor filed the notification, request a copy for your records. ESA Certificate of Acceptance.

Safety: Never pull the utility meter yourself, bypass seals, modify live service equipment, or attempt to arrange an unsafe informal reconnection. For exposed wires, smoke, sparking or severe equipment damage, keep away and contact the appropriate emergency/utility services.

8. What the installation timeline actually looks like

A normal project may involve a relatively short period of physical electrical work after the design and utility coordination have been completed. The total scheduling period is not the same as the installation-day outage. Hydro Ottawa recommends allowing 3–4 weeks just for advance submission of its service request, and actual lead times can be longer.

If you depend on a well pump, electrically driven sump pump, medical equipment, security system or working-from-home internet, plan for the scheduled outage and the possibility of delays. An electrical service upgrade does not, by itself, provide backup power during an outage.

9. Can you avoid upgrading to 200 amps?

Sometimes. A qualified design may meet household needs without increasing the incoming service, especially when the original issue is panel space rather than load. Options to discuss include:

• A properly assessed lower-current or adjustable Level 2 EV charger, where supported and permitted.
• A code-compliant EV charging load-management arrangement designed for the existing service.
• A replacement panel or subpanel where additional breaker spaces are needed but the service rating is adequate.
• Adjusting planned appliance choices or the sequence of renovations to fit a documented capacity plan.
• Completing the service upgrade now if the documented future-load calculation shows it is genuinely needed.

None of these options is universally suitable. Equipment certification, electrical code, manufacturer instructions and service conditions matter. Ask the LEC why the recommended option passes the load calculation and what future expansion it leaves available.

Example decisions — not automatic approvals

10. Comparing Ottawa electrician quotes: homeowner checklist

Give two or three Licensed Electrical Contractors the same project description wherever practical. Otherwise, the apparent lowest bid may omit the most expensive parts of the work.

Before requesting prices:

• List every new load planned over the next few years: EV, heat pump, hot tub, induction range, suite or workshop.
• Identify your actual distributor from your electricity bill.
• Provide safe photos of the closed panel, its visible labelling and the exterior service entrance.
• Mention overhead/underground supply, private poles, buried utilities and access constraints.
• Ask for an on-site or otherwise sufficiently documented electrical assessment and load calculation.

Before accepting a quote:

• Verify the electrical business's ECRA/ESA licence using the official ESA guidance.
• Confirm whether it is a panel replacement, service upgrade or both.
• Require an itemized breakdown of panel, mast/meter, service conductors, grounding, ESA fees and utility coordination.
• Ask the contractor to explain the load calculation and why the recommended amperage is suitable.
• Agree who pays utility customer-layout and connection charges, excavation and restoration.
• Confirm the planned outage, service inspection, reconnection and any contingency for a delayed restoration.
• Check materials, warranties, insurance and how unexpected conditions or change orders will be handled.

After completion:

• Request the ESA Certificate of Acceptance and any utility connection/authorization records supplied to the homeowner.
• Keep the final invoice, updated panel directory, product information and warranty documents.
• Save the load-calculation summary for future EV, heating or renovation decisions.

Official starting points: Hydro Ottawa service requests · Hydro One connection and upgrade information · ESA electrical inspections.

Editorial note (reviewed October 16, 2026): This homeowner guide provides general information rather than electrical engineering design or legal advice. The qualified contractor and electricity distributor must determine your home's applicable capacity, equipment, approvals and cost. Published contractor prices are illustrative advertisements, not verified Ottawa averages; fees and processes can change.