100A panel? Don't panic
Panel upgrade vs EVEMS in Markham
Many Markham homes, especially older ones in Unionville, Markham Village and Milliken, have 100A service. You can often add a Level 2 charger without a $3,000+ panel upgrade.
Four ways to fit a charger on your panel
There are four ways to find out what your home needs before spending thousands. The most expensive option is rarely the first one to try.
Option 1
Direct circuit
Panel has spare capacity and breaker space (common with 200A service).
$800 – $1,400
Option 2
Measured-demand calculation
Home uses far less than the conservative default calculation, e.g. gas heat and gas appliances.
Same as a simple install
Option 3
EVEMS load management
100A home that is tight on paper but has room in practice.
$2,000 – $3,000
Option 4
200A upgrade
Heat pump, secondary suite, multiple EVs or no workable alternative.
Quoted separately; typically several thousand dollars
What an EVEMS does
Illustration: an energy-management device at the panel and the charger it controls.
A load manager, such as the DCC-12 type devices, sits at the panel and watches total household draw. If your usage approaches the limit it throttles or pauses the charger, then restores charging when big loads such as the oven or dryer switch off. For most households the car is still full by morning. It is a code-recognized way to prevent overloading the service.
STEP 1
Monitor
Sensors at the panel watch total household current in real time.
STEP 2
Throttle
When the oven, dryer and heat run together, the charger eases back or pauses.
STEP 3
Restore
As big loads cycle off, charging ramps back up to full speed.
A day on a 100A service with an EVEMS
■ Household load ■ EV charging using only the room left - - service limit. Illustrative example, not a measurement of your home.
We'll tell you honestly whether you need the upgrade.
How the code calculation works
The Ontario Electrical Safety Code sizes service conductors with a prescriptive calculation that tends to be conservative. In some circumstances the code lets a Licensed Electrical Contractor use measured maximum-demand data for the home instead (see Section 8 and the ESA's published bulletins on maximum circuit loading and demand factors). Whether that applies to your house is a professional judgement, and the inspection still has to pass. We will tell you honestly if your home does not qualify.
When to just upgrade
If you are planning a heat pump, adding a basement suite, or buying a second EV, a 200A service may be the cheaper path over time. A full upgrade involves the utility (in most of Markham, Alectra), a new panel and mast, and a complete ESA inspection.
See what each option costs on the pricing page.
Frequently asked questions
Can I add an EV charger to a 100A panel?
Often yes. Depending on your loads, a load calculation based on measured demand or an EV energy management system can make room without replacing the service. An electrician has to run the numbers for your specific home.
What does an EVEMS do?
It monitors total household current and pauses or reduces the EV charger when the home approaches its limit, then restores charging when other loads cycle off. Your car still ends up charged by morning in most households.
When is a 200A upgrade the right call?
When you are adding a heat pump, a secondary suite, a second EV or other large loads, or when the panel has no usable breaker space and no practical alternative.
Find out if you need the upgrade
Fixed written price before any work starts. We reply within 2 business hours.