Galvanized Rigid Steel/Metallic Conduit Pipe (GRC)

1. What is Galvanized rigid steel pipe conduit

Galvanized rigid steel conduit is manufactured from mild steel, it is used as a steel raceway system for electric conductors. The shape is circular cross-section, designed for the physical protection and routing of wire conductors and use as an equipment grounding conductor.

Galvanized rigid steel conduit is the heaviest weight and thickest wall of electrical conduits. It is made of low carbon steel pipe with accurate round section, uniform wall thickness, free inner surface and continuous weld.

Metallic Conduit Pipe

Metallic Conduit Pipe (GRC) is another calling of rigid steel conduit.

2. Feature of the GRC

1). Hot-dip galvanized for excellent corrosion resistance
2). High strength ductile steel for long life and easy bending.
3). Smooth, continuous raceways for fast wire pulling.
4). Kwik-release end cap to protect threads
5). True color galvanized rigid steel conduit special orders available.
6). Complied to Safety standard UL 6.
7). Manufactured according to ANSI C80.1
8). Sizes from 1/2 inch t o 6 inch. 16mm to 155mm.

3. Pipe Conduit Specification

1). Electrical Rigid Steel Conduit (ANSI C80.1)

This standard ANSI C80.1 covers the requirements for electrical rigid steel conduit for use as a raceway for wires or cables of an electrical system. Finished conduit pipe is produced in nominal 10 ft(3.05 m) lengths, threaded on each end with one coupling attached. It is protected on the exterior surface with a metallic zinc coating, or alter corrosion protection coating and on the interior surface with a zinc or organic coating.
This standard also covers conduit couplings, elbows, nipples and conduit lengths other than 10ft(3.05 m)

2）Electrical Rigid Metal Conduit-Steel (UL6)

These requirements cover electrical rigid metal conduit-steel, elbows, couplings, and nipples for use as a metal raceway for installation of wires and cables in accordance with CSA C22.1, Canadian Electrical Code, Part 1, and NFPA 70, National electrical Code. ERMC-S is provided with a zinc, zinc-based, nonmetallic, or other alternate corrosion-resistant exterior coating and an organic or zinc interior coating. It is the user’s responsibility to determine the appropriate product for their application.

4. Requirement for galvanized rigid steel conduit

1). Interior and outside coating surface

The interior surface shall be free from injurious defects. Hot-dip galvanized interior and outside to provide galvanic corrosion layer protection. Although top coated with a compatible organic layer to protect from white rust. The inside surface is coated evenly for wire-pulling ease, even through multiple 90° bends.

2). Welding

The welding of all seam  shall be continuous and done in a workmanlike manner.

3). Cleaning

The conduit shall be adequately cleaned before the application of the protective coating. The cleaning process shall leave the exterior and interior surfaces of the conduit in such a condition that the protective coating shall be smooth and adhere firmly.

4). Protective coating for corrosion resistance

a. The exterior surface

The exterior surface shall be either thoroughly and evenly coated with metallic zinc or protected with an alternate corrosion resistance coating (ACRC).

b. The interior surface

The interior surface shall be protected by a zinc, or an organic coating. The interior coating shall have a smooth continuous surface. An occasional variation due to uneven flow of coating shall be acceptable.

5). Surface treatments

Any surface treatment not exceeding 0.00015 inch (0.0038 mm) that is employed as a topcoat or conversion coating is not required to meet the requirements for an ACRC or organic coating.

5. Galvanized rigid steel conduit dimensions

Available in sizes 1/2(16) -6 (155)

6. Differences between galvanized steel pipe and galvanized rigid steel conduit

In order to improve the corrosion resistance of steel pipe, the steel pipe usually needs to be galvanized. Galvanized steel pipe can be divided into two kinds, hot dip galvanized and electric zinc plating. Hot dip galvanized has the advantages of uniform coating, strong adhesion, long service life and so on. The zinc plating cost is low, and the surface is not very smooth. The corrosion resistance of zinc plating steel pipe is much worse than that of hot dip galvanized.

There are lots of common between galvanized steel pipe and galvanized rigid steel conduit, but they also have differences as below.

1). Design

Galvanized steel pipe and galvanized rigid steel pipe are multi-functional, but they are designed for different applications. The pipe ends of both types steel pipe are easy to machined, such as thread. Galvanized steel pipes can be made almost any diameter, However, the diameter of the galvanized rigid steel conduit is available between 1/2″ and 6″.

2). Application

Both types steel pipe are designed for indoor, outdoor and underground application. Galvanized steel pipe can be widely used for pipeline, such as heating pipeline and conveying gas etc. Galvanized rigid steel conduit are special designed for electrical application, it provide good protection for electrical wire.