Can I run underground electrical to my detached garage myself in New Brunswick?

No, you cannot legally run underground electrical to a detached garage yourself in New Brunswick. All electrical work in NB — including underground feed to a detached garage — must be performed by a licensed electrician and requires both an electrical permit and inspection before the trench is backfilled and the system is energized.

This is not just a technicality. Underground electrical runs involve several critical decisions that affect safety and code compliance. The wire must be rated for direct burial or run through approved conduit, the burial depth must meet Canadian Electrical Code (CEC) minimums based on the wiring method and voltage, and the connection points at both the house panel and the garage sub-panel must be properly sized, bonded, and grounded. A licensed electrician will calculate the load requirements for your garage — factoring in lighting, receptacles, a garage door opener, and any future needs like an EV charger or workshop tools — and size the feeder cable and sub-panel accordingly. Undersizing the feeder is one of the most common mistakes, and it is expensive to correct after the trench is backfilled and the garage is finished.

In New Brunswick's climate, underground electrical runs face additional challenges. The frost depth in NB ranges from 4 to 5 feet (1.2 to 1.5 metres), and while the CEC burial depth requirements for electrical conduit are typically shallower than frost depth, the trench must still be deep enough to prevent damage from frost heave, surface activity, and future landscaping. Most NB electricians recommend burying conduit at a minimum of 24 inches (600 mm) for rigid PVC conduit carrying 120/240V, though direct-burial cable without conduit requires deeper placement. The trench route must also avoid water lines, sewer lines, septic systems, and any other buried utilities — calling NB Power's free locate service before digging is mandatory and protects you from hitting a buried gas or power line.

Practical steps to get this done right: First, decide what you want to power in your garage — basic lighting and outlets, a workshop with 240V tools, an EV charger, a heater, or all of the above. This determines the sub-panel size (60-amp is the minimum most electricians recommend for a detached garage; 100-amp is better if you plan for a workshop or EV charging). Second, get three quotes from licensed NB electricians. Expect to pay $2,500 to $5,000 for a typical underground run of 50 to 100 feet including the trench, conduit, feeder cable, sub-panel, and basic circuits inside the garage. Longer runs, rocky soil, or heavy-duty electrical needs push costs higher. Third, your electrician will pull the electrical permit, coordinate the inspection, and ensure everything meets the CEC and local NB requirements.

While you cannot do the electrical work yourself, you can save money by digging the trench yourself before the electrician arrives — most electricians are happy to let the homeowner handle the excavation as long as the trench meets the required depth and width. This can save $500 to $1,000 in labour. Just be sure to call for utility locates first and leave the trench open for inspection before backfilling. For help finding a licensed electrician experienced with garage electrical in your area, browse the New Brunswick Construction Network directory at newbrunswickconstructionnetwork.com.