Should my NB greenhouse have a dedicated subpanel?

For a greenhouse in New Brunswick, a dedicated subpanel is almost always the right choice — and in many cases, it's practically necessary given the electrical demands of a working greenhouse.

Greenhouses are surprisingly power-hungry. Between grow lights (especially HID or LED arrays), heating systems, ventilation fans, irrigation pumps, thermostats, and humidity controls, a modest greenhouse can easily pull 30–60 amps continuously. Running all of that back to your main panel through a single circuit isn't just inconvenient — it's a code violation waiting to happen. A dedicated subpanel, typically 60A or 100A, lets you distribute those loads properly across multiple circuits, each sized correctly for its purpose.

Why a Subpanel Makes Sense for NB Greenhouses

The Maritime climate adds a layer of complexity that makes proper electrical planning even more critical here. New Brunswick winters mean your heating systems will run hard from November through April, and ice storms can cause power fluctuations that stress electrical systems. A subpanel gives you a local disconnect point — if something trips or goes wrong inside the greenhouse, you're not running back to your main house panel in the middle of a February ice storm.

Moisture is the other major factor. Greenhouses are wet environments by definition — humidity, condensation, and irrigation water create serious electrical hazards. Your subpanel enclosure must be rated for wet or damp locations (NEMA 3R minimum, NEMA 4 preferred), and virtually every circuit inside the greenhouse will require GFCI protection under the Canadian Electrical Code. This is non-negotiable in a wet location environment. All receptacles, lighting circuits, and equipment circuits need GFCI protection — a subpanel with GFCI breakers makes managing this much cleaner.

What TSANB Requires

This project requires a TSANB permit — you're adding a new subpanel and multiple new circuits, which is squarely in permitted work territory. Your licensed electrician will pull the permit, complete the work to CEC standards, and a TSANB inspector will sign off before the panel is energized. Don't skip this step; unpermitted electrical work in a wet location like a greenhouse is a serious fire and insurance risk.

Typical costs for a subpanel installation in New Brunswick run $800–$1,500 for the panel itself, plus the cost of running the feeder from your main panel (which depends on distance) and wiring the individual circuits inside the greenhouse. A realistic all-in budget for a properly wired greenhouse electrical system is $2,500–$5,000+ depending on size and complexity.

If your greenhouse is detached from your home, the underground feeder run also needs to account for New Brunswick's frost depth — burial depth requirements typically mean going 1.2m or deeper to protect the conduit from frost heave damage. Confirm the exact requirement with your electrician and TSANB.

New Brunswick Electrical can match you with a local licensed electrician who can assess your greenhouse layout, calculate your load requirements, and give you an accurate quote. The matching service is completely free — get started and have an electrician out to take a look before you start buying equipment.