GI steel conduit and PVC conduit both route and protect electrical wiring, but they are not interchangeable by material name alone. Compare the specific conduit system, fittings, installation environment and local electrical requirements before comparing price.
Galvanized steel offers a metallic raceway; PVC is non-metallic and does not rust. Mechanical performance, permitted locations, temperature limits and installation details depend on the exact product and its classification. This guide is a purchasing checklist, not an electrical installation design.
In this guide
- 1. Quick comparison
- 2. Identify the actual conduit system
- 3. Mechanical and environmental protection
- 4. Bonding, shielding and fire requirements
- 5. Compare installed cost
- 6. Quotation checklist
1. Quick comparison
| Consideration | GI steel conduit | PVC electrical conduit |
|---|---|---|
| Material | Steel with a protective zinc coating. | Non-metallic PVC formulated for electrical conduit. |
| Mechanical protection | Check the specified conduit type, wall thickness and impact/compression classification. | Check product class and permitted exposure to physical damage; not all PVC conduit is light duty. |
| Corrosion | Check the coating and suitability for moisture, chemicals and the installation location. | Does not rust, but chemical, UV and temperature suitability still need checking. |
| Connections | Threaded, set-screw, compression or other system-specific fittings. | Specified solvent-cement or other product-specific joints. |
| Grounding/bonding | May be an accepted grounding path only for an eligible, correctly installed system. | Does not provide a conductive equipment-grounding path. |
| Thermal movement | Follow the specified support and movement provisions. | Thermal expansion and contraction can require specific design provisions. |
| Cost | Compare the complete installed system, not just tube price. | Often lighter to handle, but fittings, supports and installation requirements still affect cost. |
2. Identify the actual conduit system
“GI” describes galvanized material; it does not uniquely identify an electrical conduit standard. A metric steel conduit, EMT, IMC and rigid metal conduit can differ in dimensions, wall thickness, connection method and permitted use. Do not assume a fitting matches because the trade size sounds similar.
PVC electrical conduit is also different from ordinary PVC water pipe. Use the product designated for the electrical installation, with the correct fittings. The CANTEX electrical-conduit FAQ illustrates how permitted locations and product limits vary between rigid PVC conduit, utility duct and flexible ENT. Those permissions are specific to the products and code context discussed there, not universal approval for another supplier’s conduit.
3. Mechanical and environmental protection
Impact, compression and concealed installation
Both metal and PVC systems may be used in concealed or concrete-embedded installations when the selected system and local rules permit. Specify the required protection during construction as well as in service: handling, reinforcement movement, vibration, supports and cable pulling can all affect the finished run.
Do not assume steel conduit is drill-proof, or that all PVC conduit is suitable only for residential work. Ask for the mechanical classification and installation instructions. Replacing a damaged concealed run can cost more than the initial material saving.
Moisture, corrosion, sunlight and temperature
For galvanized steel, confirm the coating specification and how cut ends, seams, connections and damaged areas are handled. A coating designation alone does not establish suitability for every wet, buried, coastal or chemically exposed location.
PVC does not rust, but “plastic” does not automatically mean suitable for every chemical, outdoor exposure or operating temperature. Ask for the exact product’s permitted use and UV/temperature limits. Include thermal movement and support arrangements in the design review rather than assuming the same spacing and fittings as steel.
For example, CANTEX’s installation guidance addresses thermal expansion and contraction for its PVC systems. Use the selected manufacturer’s current instructions for the actual project.
4. Bonding, shielding and fire requirements
Electrical continuity is not automatic compliance
Metal conduit and fittings must be bonded and installed as required by the applicable electrical design. Do not omit a protective conductor merely because a tube is metal, or treat an unverified metric set-screw system as equivalent to a listed RMC, IMC or EMT system.
NEMA’s steel-conduit grounding research concerns specified galvanized steel RMC, IMC and EMT systems. It does not prove the grounding performance or listing status of every galvanized tube. PVC itself cannot serve as a conductive equipment-grounding path; the designer must specify the required protective conductors and bonding arrangements.
Shielding and life-safety circuits
Metal raceways can contribute to electromagnetic shielding, but effectiveness depends on the entire installation, including joints and bonding. Do not make a generic shielding claim into a guaranteed EMC result.
Steel’s non-combustibility does not make a wiring circuit fire-survivable. For fire alarm, emergency power or other life-safety circuits, confirm the cable, conduit, boxes, supports, penetrations and any required tested-system evidence together. PVC flame-test results also do not establish a complete circuit’s fire endurance.
5. Compare installed cost, not tube price alone
A useful comparison includes conduit, compatible fittings and boxes, supports, protective conductors, cutting/bending tools, labour, transport and the cost of meeting the specified environment. Consider access for maintenance and the consequences of damage before choosing an alternative.
6. Information to include in a quotation request
- Applicable electrical standard, project location and specified conduit type.
- Nominal designation, actual outside diameter, wall thickness or classification, length and quantity.
- Concealed, concrete-embedded, exposed, buried, wet or other installation conditions.
- Required coating, corrosion protection, sunlight and temperature performance.
- Connection method and a matching list of couplings, connectors, bushes, boxes and supports.
- Required product certification, mechanical classification and bonding/grounding provisions.
- Packing, labelling and the project’s required inspection or approval documents.
If an alternative is proposed, have the responsible electrical designer check the complete system before substitution. For CanHope enquiries, send the drawings and specification to info@canhopesteel.com; confirm actual availability and supporting documents in the quotation.