How to Install a Conduit for Outdoor Wiring

Running power to a shed, a detached garage, or an exterior fixture on a Toronto or GTA home almost always means conduit somewhere along the route — either the whole run or just the exposed section leaving the building. Conduit protects the conductors mechanically and, done right, keeps water out for decades. This guide covers the actual materials, fittings, and mounting rules.

How to install a conduit for outdoor wiring

Outdoor conduit in Ontario is typically rigid PVC (Schedule 40 or 80) for surface-mounted runs, or rigid metal conduit where additional mechanical protection is needed. Every joint uses solvent-welded (PVC) or threaded (metal) fittings rated for wet locations, every conduit run is secured to the structure with weatherproof straps at intervals the Ontario Electrical Safety Code specifies, and every above-grade termination point (a weatherproof box, a service head, an LB fitting) is sealed against water intrusion. Any new outdoor circuit requires an ESA notification through an ECRA/ESA-licensed contractor.

Conduit vs direct-burial cable

Two approaches exist for getting power outdoors, and they are not interchangeable:

• Conduit with individual THWN/RW90 conductors pulled inside: the conduit itself provides the mechanical protection; conductors can be replaced or added later by pulling new wire through the existing pipe. Standard for surface-mounted runs up a wall, through a wall penetration, or in exposed locations.
• Direct-burial cable (NMWU or equivalent) with no conduit: the cable jacket itself is rated for direct soil contact. Common for underground runs to a shed or detached structure. See how to bury electrical wire safely in the yard.

A single run often combines both: direct-burial cable underground, transitioning into conduit at the point it rises above grade to enter a building or connect to a fixture.

Materials for surface-mounted outdoor conduit

• Rigid PVC conduit (Schedule 40): most common residential choice — lightweight, corrosion-proof, solvent-welded joints. Suitable for most GTA outdoor runs.
• Rigid PVC (Schedule 80): thicker wall, added mechanical protection where impact risk is higher (near a driveway, low mounting height).
• Rigid metal conduit (RMC) or intermediate metal conduit (IMC): used where maximum mechanical protection is required, threaded fittings, more labour-intensive to install.
• Liquid-tight flexible conduit: for the final connection to equipment that vibrates or needs slight movement allowance, such as an AC condenser disconnect.

Step-by-step: a typical surface-mounted run

1. Plan the route, minimizing bends and keeping the total bend angle between pull points within code limits.
2. Kill power at the source breaker before any work at the panel or existing circuit tie-in.
3. Mount a weatherproof LB fitting or condulet at the wall penetration point, sealed against the exterior surface.
4. Run PVC conduit sections, solvent-welding each joint with primer and cement rated for electrical conduit.
5. Secure the conduit to the wall with weatherproof straps at the spacing the OESC requires — typically every 1–1.5 m plus within a short distance of each fitting or box.
6. Install a weatherproof junction or device box at the termination point, using a listed gasketed cover.
7. Pull the appropriately sized and rated conductors through the completed conduit run.
8. Terminate at both ends, torque to spec, and confirm the installation with a licensed contractor before energizing.

Sealing details that determine whether it stays dry

• Every fitting on a wet-location run needs a gasket or listed weatherproof rating — standard interior fittings are not sufficient outdoors.
• Duct seal at conduit entries into a panel or enclosure prevents warm indoor air from condensing inside the cold conduit, the same principle covered in how to seal conduit entering the breaker box.
• A drip loop at any point conductors exit into open air directs water away from the entry rather than letting it track straight in.
• Weep holes at any LB fitting’s low point let condensation that does form drain out rather than pool.

Support spacing and clearance

• Straps secure the conduit at regular intervals along its length, with tighter spacing near fittings and boxes.
• Clearance above grade should account for snow accumulation in Ontario winters — mounting low enough that a plowed snowbank buries the conduit invites damage.
• Where conduit crosses a driveway or is subject to vehicle traffic, burial depth or physical protection requirements are stricter than a simple lawn crossing — see how deep should a trench be for an electrical line.

Common conduit installation mistakes

• Using indoor-rated fittings outdoors — they lack the gasket and rating to stay sealed against weather.
• Skipping primer before PVC solvent welding, leaving joints that look bonded but are not chemically fused and can leak or separate.
• Insufficient strap spacing, letting the conduit sag and eventually crack at a stress point.
• No drip loop at open conductor exits, letting water track straight into the box.
• Mounting height too low for realistic snow load in the location.

Expert tip from our ESA-licensed electricians

The outdoor conduit failures we get called to fix in the GTA are rarely about the conduit material itself — they are almost always a fitting that was never actually sealed properly, sometimes because the installer skipped the gasket, sometimes because a standard indoor connector was used where a weatherproof one belonged. If you are pricing an outdoor conduit job, ask specifically what fitting type is being used at every joint and termination, not just what the conduit itself is made of. That is where the water actually gets in.

Frequently Asked Questions

Do I need conduit if I use direct-burial cable?

Not underground, but the point where it rises above grade typically transitions into conduit for mechanical protection.

Is PVC conduit strong enough outdoors?

Yes, Schedule 40 is standard for most residential outdoor runs, with Schedule 80 for higher impact-risk locations.

Can I install outdoor conduit myself?

Under the homeowner exemption on a primary residence, yes. ESA notification and inspection are still required.

What happens if a fitting is not weatherproof?

Water tracks in, corrodes the connections, and can eventually reach the panel through the conduit run.

Does outdoor conduit need GFCI protection?

Any receptacle or fixture it feeds outdoors requires GFCI protection under current Ontario code.

Related reading from ezsmart.ca

• How to Bury Electrical Wire Safely in the Yard
• How Deep Should a Trench Be for an Electrical Line?
• How to Seal Conduit Entering the Breaker Box
• Can Water Get Inside an Outdoor Breaker Box?
• How to Wire a Shed for Electricity?

Contact us

Planning an outdoor electrical run in a Toronto or GTA yard? Call ezsmart at 416-838-9006 or use our contact page. An ESA-licensed electrician will install conduit that stays sealed for the long haul.