When assessing renovations, the electrical panel is examined first to determine if it needs upgrading. If the panel is degraded or lacks adequate space for new circuits, it may need to be replaced or a subpanel added. The home's electrical service is also analyzed through a demand load calculation accounting for the home size and appliances. If upgrades are required due to insufficient capacity, options like changing to an overhead service or gas appliances are considered. Safety is the top priority in these calculations, as undersized systems pose fire and shock risks.

1. When I am Renovating, Do I need to Increase the Size of my Electrical Panel?
This is a question that is sometimes asked by clients when we assess renovation projects but it is a
question we always ask ourselves. As a matter of fact, looking at the electrical panel is usually where
we begin.
The electrical panel usually gives us an idea of the general health of the wiring in the home. If we see
sloppy wiring, code infractions and safety concerns, they need to be rectified and must be included in
the client’s renovation budget. Beyond that, we estimate the number of new circuits required by the
renovations and, if there are inadequate breaker spaces in the existing panel, it is usually a simple
matter of adding an adjacent subpanel. In rare cases we will replace the existing panel with a larger
one. This is usually done with older panels which are showing signs of degradation or have
inadequate grounding hardware.
We also look at your electrical service, which is the cable running to your home from the power
company to your meter, the meter box itself, and the wiring from the meter to the panel. If we feel that
your electrical service may be undersized, we conduct a Demand Load Calculation according to the
Canadian Electrical Code. That calculation includes a factor for the finished area of your home plus
additional considerations for electrical loads over a certain wattage. Some of the items which may
increase the draw on your electrical service are double wall ovens, convection cook tops, electric
heating, electric floor warming, electric snow melting, air conditioning, jacuzzis and hot tubs.
The Demand Load Calculation results in a figure in amps and we compare that to the current rating of
the main breaker in your panel. If the calculated demand is less than the main breaker rating, then no
upgrades are required. If the calculation exceeds your system rating, however, some decisions need to
be made and they usually relate to cost.
A service change with overhead supply lines is relatively simple and inexpensive. It usually involves
changing the existing meter box and conduit, installing heavier conductors and arranging with the
power company to provide new supply lines. An underground supply, however, can involve trenching
back to the utility pole or transformer and can be much more expensive.
Once a cost for the service change is estimated, the client decides how that figure works within the
renovation budget. Sometimes a change from electric to gas appliances can eliminate the need for a
service change. In other cases, if the demand load is only slightly higher than the capabilities of the
existing system, we can provide switching of loads from one to another, either manual or automatic,
which ensures that two heavy loads cannot operate at the same time. This will bring us within
tolerance.
As a contrator, we don’t play games with Demand Load Calculations. These are hard calculations that
concern client safety and are mandated by the electrical code. We have lost jobs on this issue but we
don’t say, “I think you can get away with it”. An electrical inspector once said to me, “If you wouldn’t
do it in your own home, then don’t do it in someone else’s”. It’s a philosophy we live by. We like to
sleep at night and we know you do as well.
Neil Edwards,
Alberta Master Electrician