How do I size a NB shed subpanel for tools?

For a typical workshop shed in New Brunswick, a 60A subpanel is the most common and practical choice — though your actual tool load may push you toward 100A if you run multiple large tools simultaneously.

Sizing a shed subpanel correctly comes down to calculating your actual load, planning for future tools, and meeting TSANB requirements for detached structure wiring. Getting this right the first time saves you from an expensive upgrade down the road.

Calculate Your Tool Load First

Add up the amperage of everything you plan to run. A table saw draws 12-15A, a dust collector 10-12A, an air compressor 15-20A, and shop lighting another 5-10A. If you're running a welder, that alone can pull 30-50A depending on the machine. The key question isn't just peak draw — it's how many tools you might run at the same time. Most hobbyist woodworkers find 60A more than adequate. Serious metalworkers or anyone running a welder plus compressor simultaneously should look at 100A.

A practical rule: calculate your maximum simultaneous load, then size the subpanel at least 25% above that number. Electrical capacity is cheap to add during installation and expensive to upgrade later.

NB-Specific Wiring Considerations

In New Brunswick, the Canadian Electrical Code (CEC) governs detached structure wiring, enforced by TSANB. A few things matter here specifically:

The feeder wire from your house to the shed is often the most expensive part of the job. Underground runs in NB must account for frost depth — burial depth for electrical conduit is typically 600mm minimum for conduit, 900mm for direct-buried cable under normal conditions, but your electrician will confirm based on your specific installation. Given NB's frost depth can reach 1.2-1.5m, proper burial is critical to avoid frost heave damage.

Your shed subpanel must be a 4-wire feed (two hots, neutral, and ground) per current CEC requirements — the ground and neutral must be kept separate at the subpanel, unlike at your main panel. The subpanel itself needs proper clearances: 1 metre of clear working space in front of the panel.

A TSANB permit is required for this work — no exceptions. Your licensed electrician pulls the permit, completes the work, and a TSANB inspector signs off before you energize the panel.

Typical Costs in New Brunswick

Expect to pay $800–$1,500 for subpanel installation if your main panel has capacity and the shed is reasonably close (under 30m). Longer runs, trenching through landscaping, or needing a main panel upgrade will push costs higher — potentially $2,500–$4,500 for a full project with panel upgrade included. Get quotes from at least two licensed electricians.

Don't Undersize It

The most common mistake homeowners make is sizing for today's tools, not tomorrow's. A 60A panel costs only marginally less than a 100A panel, but the labour and trenching cost is identical either way. If there's any chance you'll add an EV charger in the shed, a welder, or a spray booth with ventilation, go 100A from the start.

New Brunswick Electrical can match you with a licensed local electrician to assess your specific shed setup and provide a free estimate — reach out and we'll connect you with someone in your area.