Comparing PVC and Metal Conduit for Outdoor Electrical Projects

Revco Lighting + Electrical Supply — Serving the industry since 1978

Contractors know this: pick the wrong conduit, and it’s not just a materials issue—it’s a callback, a code violation, or worse. Whether you’re wiring a home exterior or trenching a commercial lot, the conduit you choose has to match the environment, the install method, and the local code. This guide walks through when to use PVC, when to go metal, and what each brings to the job site.

PVC vs. Metal Conduit: What You Need to Know

Both PVC and metal conduit are approved for outdoor use under the National Electrical Code (NEC). Each has strengths—and limits—you should know before buying.

Installation Differences That Matter

Tools & Techniques

PVC conduit installation typically requires:

• PVC cutters or saw

• Primer and solvent cement

• Expansion fittings for outdoor runs

• Basic hand tools

Metal conduit installation often involves:

• Conduit bender

• Pipe cutter or hacksaw

• Reamer or deburring tool

• Threading dies (for RMC/IMC)

• Compression or set-screw fittings

PVC joints are chemically bonded for a watertight seal. Metal conduit is joined with mechanical fittings that may require grounding continuity.

Weight & Handling

A 10-foot stick of 1-inch PVCweighs around 3.3 pounds. A 10-foot stick of 1-inch EMT weighs about 6.7 pounds. The lighter weight of PVC makes it easier for overhead work and long runs, especially with smaller crews.

Labor Skills

Metal conduit bends cleanly with the right tools but takes experience. PVC can’t be cold-bent—it’s cut and joined with fittings or heated carefully for sweeps. If you're training up an apprentice or trying to speed up a tight job, PVC usually installs faster.

Cost Breakdown: Material vs. Lifecycle

PVC costs less up front. But in areas where conduit takes physical abuse—like parking lots or loading docks—metal’s longer life and impact resistance may pay off in fewer repairs and replacements.

When to Use Metal Conduit Outdoors

High-Impact Zones

• Commercial walkways

• Garage and carport areas

• Equipment yards

• Places where conduit sits under 8 feet

Steel conduit stands up to collisions, kicks, and weed trimmers. PVC cracks where metal dents.

Commercial & Industrial Sites

Metal is often required by code for:

• Public-access installations

• Exterior building walls

• Parking garages

• Loading docks

Metal also supports grounding through the raceway itself (NEC 250.118), reducing the need for separate grounding conductors—though many pros still pull a ground for redundancy.

When to Use PVC Conduit Outdoors

Corrosive Conditions

PVC is a first pick for:

• Coastal areas (salt spray)

• Fertilizer zones (landscaping)

• Underground work

• Damp or flood-prone sites

Unlike metal, it won’t rust. Even galvanized steel eventually loses its protection once coatings wear thin.

Underground Runs

PVC is preferred for buried conduit:

• Approved for direct burial (Schedule 40)

• Lightweight and easier to feed wire through

• Chemically stable in soil

• Lower cost for long trench runs

Budget-Friendly Residential Installs

PVC is a great match for:

• Detached garages

• Exterior GFCI runs

• Patio or deck lighting

• Pool and hot tub circuits

Easy to cut. Easy to glue. No threading. And if you're a homeowner or low-voltage contractor without heavy bending tools, it's the obvious choice.

Outdoor Hazards: How the Two Compare

Sunlight

Use sunlight-resistant(UV-rated) PVC for any above-ground outdoor run. Basic white PVC will chalk, embrittle, and crack if left exposed.

Metal conduit doesn’t degrade in sun, but its coating scan fade or peel over time—especially in salt air.

Heat and Cold

PVC loses strength in high heat and can become brittle in extreme cold. Its code-listed ambient max is 122°F. In high-swing climates, use expansion fittings (required when runs exceed 25 feet and temperature change exceeds 60°F).

Metal holds up across a wider range and doesn’t expand or contract as dramatically.

Water

PVC is impervious to moisture. Metal resists water if its coatings remain intact. Once scratched or cut, corrosion can creep in—especially at fittings or bends.

Installation Tips from the Field

• Support spacing: Max 3 ft for ½–1" PVC (NEC 352.30); up to 10 ft for EMT (NEC 358.30)

• Expansion joints: Required for long PVC runs outdoors; allow 3/8 inch movement per 10 feet per 100°F swing

• Drainage: Slope conduit runs and use drain fittings at low points to avoid condensation buildup

• Oversize when possible: One trade size up eases wire pulls and supports future upgrades

What the NEC and Real-World Use Say

Always check:

• NEC 2023for Articles 352 (PVC), 358 (EMT), 344 (RMC), and 342 (IMC)

• Local code amendments

• Utility service rulesfor meter entries and outdoor feeders

Some municipalities require Schedule 80 PVC for exposed areas, while others demand metal for any conduit under 8 feet off the ground. Don’t guess—call your AHJ (Authority Having Jurisdiction).

Stocking Up for the Job

Revco carries the full range of outdoor-rated conduit and fittings:

• Schedule 40 and 80 PVC

• EMT, RMC, and IMC in multiple diameters

• Expansion joints, clamps, and pull elbows

• Outdoor-rated boxes and fittings

Visit one of our six Long Island supply counters or order online for fast delivery to your jobsite. Our counter team knows the code, the gear, and how to keep you moving.

Browse Conduit Options at Revco

Frequently Asked Questions

How long does UV-rated PVC last outdoors?
There’s no universal guarantee, but UV-rated PVC holds up for many years in normal sunlight. Still, avoid prolonged exposure to direct sun during storage.

Can I switch from PVC to metal in the same run?
Yes, use listed transition fittings with gaskets and sealant to maintain water-tightness and bonding continuity.

Which is safer during a lightning event?
Metal conduit can conduct and dissipate strike energy if bonded, but isn't a substitute for full lightning protection per NFPA 780. PVC offers isolation, not grounding.

How much space should I allow for expansion in PVC?
Use 3/8 inch of movement per 10 feet of run for every 100°F temperature differential. Outdoor runs over 25 feet usually need an expansion fitting.

Do I need a ground wire inside metal conduit?
Not always. EMT, IMC, and RMC can serve as the grounding path if all fittings are listed and tightened per code. Still, many electricians pull a dedicated ground wire for redundancy.