Conduit does more than hide wires — it protects circuits from physical damage, moisture, and accidental contact. Picking the right conduit means fewer callbacks, fewer surprise outages, and a clean install that lasts years.
Why Conduit Matters
Not all electrical installations live in climate-controlled basements or neat utility rooms. Conduit often runs outdoors, under slabs, through walls — and occasionally through areas where equipment or foot traffic create impact risks. Beyond code compliance, conduit choice affects:
- Safety: Physical threats (nails, screws, machinery) and moisture intrusion.
- Longevity: Corrosion, UV exposure, temperature swings.
- Labor: Cutting, bending, threading, and joining each take time.
- Cost: Material price, shipping weight, specialized tooling, and labor rates.
If conduit’s the shell, cable is the core. For Non-Metallic Liquidtight, Liquidtight and Flexible Steel Conduit, browse our Flexible Conduit and Wire & Cable categories.
PVC Conduit: Pros, Cons, and Applications
Pros of PVC Conduit
- Lightweight Handling: At roughly 0.12 lb/ft (½″ Schedule 40), PVC is simple to carry, feed, and secure. Fewer helpers needed when running long continuous lengths.
- Great Corrosion Resistance: No metallic components mean zero rust concerns if conduit sits in high-moisture soil or gets sprayed with corrosive cleaners.
- Non-Conductive Barrier: Grounding isn’t required for the conduit itself. Ideal when minimizing grounding paths or reducing potential shock hazards near wet equipment.
- Lower Material Cost: PVC often runs 30–40 % cheaper per linear foot than comparable metal, especially in larger diameters.
- Ease of Joining: Solvent-cement fittings (couplings, elbows, Tees) lock together in minutes—no threading machines or special cutters required.
Cons of PVC Conduit
- Lower Impact Resistance: Heavy impact (forklift bump, dropped tools) can crack or shatter PVC. In high-traffic shops or warehouses, metal might be a better choice.
- Temperature Limits: Continuous max rating around 140 °F (Schedule 40) to 167 °F (Schedule 80). Prolonged exposure above 140 °F may lead to softening or sagging under load.
- UV Degradation: Direct outdoor sun can embrittle PVC over several years unless UV-resistant variants or sunlight-blocking paint is applied.
Top Applications for PVC Conduit
- Underground Feeder Runs: PVC’s moisture resistance makes it ideal for buried applications. Browse PVC Conduit Bodies or Electrical PVC Fittings
- Exterior Wall Wet Locations: Running conduit outside without risking rust where chemical washdowns occur (food plants, carwashes).
- Cost-Sensitive Projects: Residential branch circuits or budget-limited remodels where physical threats are minimal.
Metal Conduit (EMT, Rigid, IMC): Pros, Cons, and Key Applications
Pros of Metal Conduit
- Maximum Impact Resistance: Even a dropped wrench won’t penetrate rigid steel. In warehouses or industrial plants, metal conduit endures mechanical threats that crack PVC.
- Superior Fire Performance: Non-combustible throughout; at extreme temperatures, metal maintains structural integrity where PVC would soften or melt.
- Long-Term Durability: Properly painted or galvanized metal can last decades in wet or corrosive environments—periodic inspections for coating wear keep it in top shape.
- Grounding Conductor Enclosure: Conduit itself often serves as equipment grounding path when properly joined and bonded, eliminating separate ground wire in some code applications.
Cons of Metal Conduit
- Higher Material Costs: Steel or aluminum conduit runs 25–50 % costlier per foot than equivalent PVC, with larger diameters widening the gap.
- Labor-Intensive Installation: Cutting, reaming, and threading using powered dies and hydraulic benders demands time. Each threaded joint or coupling adds minutes to installation.
- Weight & Handling: A 10′ stick of 1½″ EMT can weigh 15 lb or more. Lifting, aligning, and securing rigid lengths often requires extra manpower or lifts.
Top Applications for Metal Conduit
- Industrial & Commercial Facilities: Warehouses, manufacturing floors, and machine shops where conduit may see forklift or pallet jack impact.
- High-Ceiling Suspended Runs: Long horizontal runs beneath mezzanines or catwalks stay rigid and resist sagging.
- Areas Near Heat Sources: Boiler rooms, dry kilns, or near furnaces where ambient temps exceed 140 °F.
For conduit fittings —locknuts, bushings, grounding clips— visit our EMT Conduit Fittings page
Installation Considerations
Cutting & Joining
Cutting conduit? Start with the right tools:
- PVC: A miter saw or PVC-rated chop saw will give you fast, clean cuts. Just be sure to deburr those edges with a file so your joins stay smooth.
- Metal: For EMT or rigid conduit, reach for a rotary tubing cutter or an abrasive saw. And don’t skip the reaming tool —those burrs can chew up your wires. If you’re threading rigid, plan on some extra time. You’ll need a die head and threading machine, and threading isn’t exactly a quick step.
Bends & Supports
- PVC Bends: Factory-molded 90° or 45° sweeps up to 4″ keep things simple. Solvent-cement makes for fast, strong joins (usually just a few minutes to set).
- EMT Bends: Crank-style EMT benders handle 10°–90° bends on-site. Back-to-back 90s? That takes a little calculation and a little finesse.
Support Spacing:
- PVC Schedule 40 (above grade): Support every 3 ft. Unless you’re doing an underground run, in which case, no supports needed once you’re more than 3 ft down.
- EMT (above grade): Support every 10 ft. Tighter if you’re on a seismic site, and always check local code.
Environmental Factors
- UV on PVC: After 5–7 years in direct sun, unprotected PVC can develop hairline cracks. A quick coat of UV-resistant, non-mildewing latex paint solves that without affecting performance.
- Condensation in Metal: In unheated spaces (like warehouses), day/night swings can cause condensation inside metal conduit. Add a slight slope toward junction boxes or drains to prevent water from pooling.
Code & Safety Notes
- NEC 352 covers rigid PVC conduit. Use only listed fittings, and make sure your solvent cement is an approved brand.
- NEC 358 (EMT) and NEC 342 (IMC) require all metallic joints to be electrically continuous. Tighten locknuts and use bushings to protect your conductors from abrasion.
Grounding:
- PVC Install: Since PVC isn’t conductive, your trench must include a separate equipment ground (green or bare copper).
- EMT/IMC: The conduit itself often serves as the equipment bonding jumper — if you’re not running aluminum conductors. Always test continuity after installing to be sure.
Making the Final Call
Pick PVC When:
– Moisture or chemical corrosion risk overrides mechanical threats.
– Budget drives most decisions—PVC installs at nearly half cost of metal in many cases.
– Project timeline demands quick, solvent-welded sweeps, especially on long underground pulls.
Pick Metal When:
– Physical impact is a daily threat (forklifts in a distribution center, heavy-duty machinery in a factory).
– Job specs list continuous high ambient heat, like boiler rooms or engine rooms.
– Local inspectors or engineers require metal for daylight-visible runs or exposed ceiling grid work.
When choice isn’t obvious, consider a hybrid approach: metal where conduit lives above grade and sees risk, switching to PVC past a concrete edge and below grade. Both meet code, but combining materials keeps budgets in check while covering weak spots.
Wrapping Up
Picking between PVC and metal conduit is all about matching product performance with jobsite realities. When corrosion and budget drive decisions, PVC saves labor hours without exposing circuits to rust. When impact resistance and fire safety dominate specs, metal conduit stands up to real-world hazards.
No two jobs are identical. Material availability, regional labor rates, and local code requirements vary. Specifications subject to change—always verify manufacturer data and local codes before ordering.
