Yes, there's a significant difference in protection between RGS (Rigid Galvanized Steel) and PVC-coated RGS conduit in a saltwater environment. Here's a breakdown

RGS (Rigid Galvanized Steel):
Protection

Galvanization provides a sacrificial layer of zinc that corrodes instead of the steel. This is a decent level of protection for general outdoor use.

Pros

Strong and durable, offering good physical protection. Less expensive than PVC-coated. Electrically conductive, allowing for grounding.

Cons



Susceptible to Corrosion

Saltwater is extremely corrosive. Even with galvanization, RGS will eventually corrode in a saltwater environment, especially at joints, threads, and cut ends where the galvanizing may be damaged.

Maintenance

Will likely require periodic inspection and maintenance (cleaning, coating touch-ups) to prolong its lifespan.

PVC-Coated RGS Conduit



Protection

The PVC coating acts as a barrier, preventing the saltwater from reaching the steel underneath. This provides far superior corrosion protection in a saltwater environment. The PVC coating is specifically designed to resist chemicals and moisture.

Pros



Excellent Corrosion Resistance

The PVC coating provides a complete barrier against saltwater, greatly extending the lifespan of the conduit.

Low Maintenance

Requires significantly less maintenance compared to RGS in a corrosive environment. Good impact and abrasion resistance (from the steel underneath)

Cons



More Expensive

PVC-coated RGS is significantly more expensive than standard RGS.

Requires Special Fittings and Installation

Proper installation is critical. PVC coating must be continuous. Special PVC-coated fittings and sealing compounds are required to maintain the corrosion protection at joints and connections. Damage to the coating during installation must be repaired with appropriate touch-up compounds.

Grounding Considerations

The PVC coating is non-conductive. Proper grounding methods must be used, typically involving grounding conductors within the conduit or bonding at boxes and equipment.

Which is Better?For your situation (conduit 10' from saltwater), PVC-coated RGS is the far superior choice. While it's more expensive upfront, the extended lifespan and reduced maintenance costs will likely make it more cost-effective in the long run. The severe corrosiveness of saltwater will significantly shorten the lifespan of RGS.

Here's why PVC-coated RGS is the better option



Saltwater Proximity

Even 10 feet away, saltwater spray and humidity can still carry salt particles. These particles will accelerate the corrosion of RGS.

Long-Term Cost

While the initial cost of PVC-coated RGS is higher, you'll save money on replacement costs and maintenance due to its longer lifespan.

Reliability

PVC-coated RGS provides a more reliable and long-lasting electrical system in a harsh environment.

Important Considerations



Installation

Proper installation of PVC-coated RGS is crucial. Ensure that all fittings are properly sealed and that any damage to the PVC coating is repaired. Use only fittings specifically designed for PVC-coated conduit.

Grounding

Pay close attention to grounding requirements. Because the PVC coating is non-conductive, you'll need to use appropriate grounding methods.

Type of Saltwater

The specific salinity and composition of the saltwater can affect the rate of corrosion. Consult with a corrosion specialist or electrical engineer if you have specific concerns.

Local Codes

Always follow all applicable local electrical codes and regulations.

In Summary:

While RGS might seem like a cheaper option initially, the superior corrosion protection of PVC-coated RGS makes it the more reliable and cost-effective choice for conduit exposed near saltwater. Invest in the proper materials and installation to ensure a long-lasting and safe electrical system. Flag for review