How do I safely run power to a shed or outbuilding in New Brunswick?

Running Electrical Power to a Shed or Outbuilding in New Brunswick

Whether it's a garden shed, detached workshop, hobby barn, or she-shed, getting proper electrical power to an outbuilding requires planning, permits, and compliance with the CEC.

Planning: What Do You Need?

Before calling an electrician, determine your electrical needs:

Light-duty (shed with lights and a few outlets):

• 1–2 light fixtures, 2–4 outlets


• Maximum expected load: 15–20 amps


• Feed: Single 15A or 20A circuit from the house panel


• No sub-panel needed

Medium-duty (workshop with power tools):

• 4–8 outlets, 2–4 lights, 1–2 dedicated 240V outlets


• Maximum expected load: 30–60 amps


• Feed: 60A sub-panel


• Needs a sub-panel in the outbuilding

Heavy-duty (heated workshop, welding, machinery):

• Multiple 120V and 240V circuits, heating, heavy lighting


• Maximum expected load: 60–100+ amps


• Feed: 100A sub-panel


• May require a panel upgrade at the house

Underground vs. Overhead Feed

Underground (most common for permanent outbuildings):

| Method | Burial Depth | Cable Type | Cost |
|--------|-------------|-----------|------|
| NMWU direct burial | 600mm (24") minimum | NMWU rated for direct burial | $3–$8/metre |
| Cable in rigid PVC conduit | 450mm (18") minimum | NMWU or THWN in conduit | $5–$15/metre |
| TECK cable direct burial | 600mm (24") minimum | Armoured TECK cable | $8–$20/metre |

In NB's freeze-thaw climate, burying deeper than minimum (30–36 inches) reduces the risk of frost heave damaging the conduit or cable. Rocky ground (common in many NB properties) may require conduit for protection against sharp rock.

Overhead (for short spans or when trenching is impractical):

• Minimum clearances: 3.5m over walkways, 4m over driveways, 5.5m over areas accessible to vehicles


• Uses triplex or quadruplex cable on a messenger wire


• Attachment points must be structurally sound (house and outbuilding)


• Less expensive for short distances but visually more obtrusive

Sub-Panel Requirements

If you're installing a sub-panel in the outbuilding (recommended for anything beyond a single circuit):

• Separate ground bus and neutral bus — in a sub-panel, ground and neutral must NOT be bonded together (unlike the main panel where they are bonded)
• Ground rod at the outbuilding — the CEC requires a grounding electrode (ground rod) at a separate building with a sub-panel
• Disconnect — a means of disconnect must be provided at or near the outbuilding. This can be the sub-panel's main breaker.
• Panel size — install more capacity than you currently need. A 100A panel with space for 20+ circuits costs only $50–$100 more than a 60A panel and gives room for future expansion.

GFCI and AFCI Requirements

All receptacles in outbuildings require GFCI protection per the CEC. This can be accomplished with:

• GFCI receptacles at each outlet location, or


• GFCI breakers in the sub-panel protecting each circuit

For outbuildings used as habitable space (home office, studio, guest house), AFCI protection may also be required on 15A and 20A circuits serving receptacles in living areas.

Step-by-Step Process

Plan the layout — mark outlet and light locations in the outbuilding, determine the feed size needed

Hire a TSANB-licensed electrician — they'll assess your main panel capacity and plan the feed route

Obtain TSANB electrical permit — your electrician handles this

Trench or plan overhead route — you can save money by digging the trench yourself (hand-dig or rent a trencher for $200–$400/day)

Electrician installs the feed cable — from main panel to outbuilding

Install sub-panel in the outbuilding with ground rod

Wire interior circuits — outlets, lights, switches, dedicated circuits

TSANB rough-in inspection (if walls will be closed)

TSANB final inspection

Backfill trench after underground inspection

Costs in New Brunswick

| Scenario | Total Cost |
|----------|------------|
| Single 20A circuit to small shed (15m run) | $800–$1,500 |
| 60A sub-panel to workshop (20m run) | $2,500–$5,000 |
| 100A sub-panel to large workshop (25m run) | $4,000–$8,000 |
| 100A sub-panel + heating circuit (30m+ run) | $5,000–$12,000 |
| Panel upgrade at house (if needed) | Add $2,500–$4,500 |
| TSANB permit | $75–$150 |

Cost breakdown:

• Cable/conduit materials: 30–40% of total


• Sub-panel and breakers: 10–15%


• Labour: 40–50%


• Permit and inspection: 5%

NB-Specific Considerations

Frost depth: NB's frost line is 4–5 feet. While the CEC allows 24-inch burial for NMWU, going deeper protects against frost heave. If using rigid conduit, frost heave can crack joints — use expansion fittings on long runs.

Rock: Many NB properties, especially along the Saint John River Valley and in northern NB, have shallow bedrock. If you hit rock at 12 inches, options are: route around it, use an overhead feed, or hire a mini-excavator to cut through (adds $300–$800).

Water table: Low-lying properties near rivers, in Moncton's low-lying areas, or in Fredericton's flood-prone zones may have high water tables. Use conduit with sealed fittings to prevent water from entering the cable run.

Insurance: Notify your insurance company when adding electrical to an outbuilding. Permitted and inspected work (with closed TSANB permit) supports insurance coverage. Unpermitted electrical work can void your coverage if there's a fire.

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