What a load calculation is
It adds up the electrical demand of lighting, receptacles, motors, heating, cooling and equipment, using rules from the Canadian Electrical Code. The result is compared with the capacity of the service.
It can be done for an existing building or as part of a new design.
A calculation using measured load, where possible, can show spare capacity that a simple tally would miss.
Why panel space matters
Capacity is not only about amps. A panel can be physically full even when its rating allows more load. Adding circuits may require a new panel or a sub-panel.
Spare breaker spaces make later changes cheaper.
Typical heavy loads
Commercial kitchens, dental and medical equipment, server rooms, welding or workshop equipment, and electric heating or EV chargers are common heavy loads. They often change the plan.
List all equipment with nameplate data before design.
Continuous loads, which run for three hours or more, are treated more strictly than short-term ones, so tell the electrician how equipment is used.
How we work
Our Master Electrician checks existing panels on site, records what is labelled and what is not, and compares it with your equipment list. If an upgrade is needed, we propose options with cost and lead time.
Findings are shared early, so design can adjust.
Plan for growth and safety
Label panels clearly and provide a current panel schedule. Allow spare capacity, around a fifth in many designs, and spare conduit for future runs. A tidy, labelled panel helps every future contractor.
Test breakers, tighten connections and have thermal imaging done on older panels, as part of a maintenance plan.
Questions we hear
Who performs the calculation?
A qualified electrician or engineer. Ours is led by a Master Electrician with support from our in-house engineering group.
What if the panel is full?
A sub-panel or a larger panel is the usual answer.