What is Galvanized Rigid Steel Pipe Conduit?

Galvanized rigid steel conduit, made from mild steel, serves as a steel raceway system for electric conductors. Featuring a circular cross-section, it's designed to physically protect and route wire conductors, also functioning as an equipment grounding conductor.

Galvanized rigid steel conduit is the most robust and thickest-walled among electrical conduits. Constructed from low carbon steel pipe, it boasts precise round sections, uniform wall thickness, a smooth inner surface, and continuous welds.

Metallic Conduit Pipe (GRC) is another term for rigid steel conduit.

Characteristics of GRC:

1. Hot-dip galvanization ensures superior corrosion resistance.
2. High-strength ductile steel ensures durability and easy bending.
3. Smooth, uninterrupted raceways facilitate fast wire pulling.
4. Kwik-release end cap preserves threads.
5. True-color galvanized rigid steel conduit available through special orders.
6. Conforms to safety standard UL 6.
7. Manufactured in accordance with ANSI C80.1.
8. Available in sizes ranging from 1/2 inch to 6 inches (16mm to 155mm).

Specification for Pipe Conduits

1. Electrical Rigid Steel Conduit (ANSI C80.1): This standard, ANSI C80.1, outlines the requirements for electrical rigid steel conduit used as a raceway for electrical system wires or cables. The finished conduit pipes are manufactured in nominal 10 ft (3.05 m) lengths, threaded on both ends with one coupling attached. They feature exterior protection with a metallic zinc coating or alternative corrosion protection, and interior protection with either zinc or organic coating. Additionally, this standard includes specifications for conduit couplings, elbows, nipples, and conduit lengths other than 10 ft (3.05 m).
2. Electrical Rigid Metal Conduit-Steel (UL6): These requirements pertain to electrical rigid metal conduit-steel, including elbows, couplings, and nipples, designed as a metal raceway for wire and cable installation in compliance with CSA C22.1 (Canadian Electrical Code, Part 1) and NFPA 70 (National Electrical Code). ERMC-S comes with an exterior coating of zinc, zinc-based material, nonmetallic, or other corrosion-resistant coating, along with an interior coating of organic or zinc. It is the user's responsibility to select the appropriate product for their specific application.

Requirements for Galvanized Rigid Steel Conduit:

1. Surface Coating:

• The interior surface must be free from harmful defects.
• Hot-dip galvanizing both interior and exterior surfaces provides protection against galvanic corrosion, with an additional compatible organic layer to prevent white rust.
• The inside surface should be uniformly coated for smooth wire-pulling, even through multiple 90° bends.

2. Welding:

• All seams must be continuously welded in a skilled manner.

3. Cleaning:

• Prior to applying the protective coating, the conduit must be thoroughly cleaned.
• The cleaning process should leave both exterior and interior surfaces smooth and firmly adherent for the protective coating.

4. Corrosion-Resistant Protective Coating: a. Exterior Surface:

• a.The exterior surface must be evenly coated with metallic zinc or protected by an alternate corrosion-resistant coating (ACRC).

• b. Interior Surface:The interior surface may be protected by zinc or an organic coating, ensuring a smooth and continuous surface. Minor variations due to uneven coating flow are acceptable.

5. Surface Treatments:

• Surface treatments, not exceeding 0.00015 inch (0.0038 mm), used as topcoats or conversion coatings, are not required to meet ACRC or organic coating standards.

Dimensions of Galvanized Rigid Steel Conduit

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

Trade Size	Metric Designator	Outside Diameter		Nominal wall Thickness		Approximate Weight Per 100 FT. (30.5M)		Quantity in Master Bundle
		in	mm	in	mm	lb	kg	ft	m
1/2	16	0.840	21.34	0.104	2.64	82	37.5	2500	762.5
3/4	21	1.050	26.67	0.107	2.72	109	49.4	2000	610.0
1	27	1.315	33.40	0.126	3.20	161	73.0	1250	381.3
1 1/4	35	1.660	42.16	0.133	3.38	218	98.9	900	274.5
1 1/2	41	1.900	48.26	0.138	3.51	263	119.3	800	244.0
2	53	2.375	60.33	0.146	3.71	350	158.8	600	183.0
2 1/2	63	2.875	73.03	0.193	4.90	559	253.6	370	112.9
3	78	3.500	88.90	0.205	5.21	727	329.8	300	91.5
3 1/2	91	4.000	101.60	0.215	5.46	880	399.2	250	76.3
4	103	4.500	114.30	0.225	5.72	1030	467.2	200	61.0
5	129	5.563	141.30	0.245	6.22	1520	689.5	150	45.8
6	155	6.625	168.28	0.266	6.76	1785	809.7	100	30.5

Distinguishing Galvanized Steel Pipe from Galvanized Rigid Steel Conduit

To enhance steel pipe's resistance to corrosion, it's often galvanized, a process that divides into two types: hot-dip galvanization and electric zinc plating. Hot-dip galvanized pipes offer uniform coating, strong adhesion, and extended longevity. Conversely, electric zinc plating is cost-effective but yields a less smooth surface and inferior corrosion resistance compared to hot-dip galvanization.

While galvanized steel pipe and galvanized rigid steel conduit share similarities, they also exhibit differences:

1. Design: Both are versatile, but intended for different uses. Both types feature easily machinable pipe ends, such as threading. Galvanized steel pipes can be produced in nearly any diameter, whereas galvanized rigid steel conduit diameters typically range from 1/2" to 6".
2. Application: Both types serve indoor, outdoor, and underground purposes. Galvanized steel pipes find wide application in pipelines, including for heating and gas conveyance. Galvanized rigid steel conduits, however, are tailored specifically for electrical applications, offering robust protection for electrical wiring.