Article
Steel fittings in a variety of formulations have been liquidtight 
raceway products of choice since the early days of electrical 
distribution. When these products have been galvanized, a thin zinc 
coating offers corrosion resistance for use in many outdoor and exterior
 applications where non-galvanized steel might otherwise rust through. 
But electrical wiring requires extra protection in more significantly 
corrosive environments. So, contractors need to consider materials that 
offer more advanced protection in settings where chemicals, salt spray 
and other damaging substances are common.

Adding Corrosion Protection to Liquidtight Fittings with PVC Coatings

Chuck Ross
Steel fittings in a variety of formulations have been liquidtight raceway products of choice since the early days of electrical distribution. When these products have been galvanized, a thin zinc coating offers corrosion resistance for use in many outdoor and exterior applications where non-galvanized steel might otherwise rust through. But electrical wiring requires extra protection in more significantly corrosive environments. So, contractors need to consider materials that offer more advanced protection in settings where chemicals, salt spray and other damaging substances are common.  

Stainless steel is one choice for these projects, but it’s expensive. Coating galvanized steel fittings and conduit with Polyvinyl chloride – PVC, for short – can be a more affordable option. This material creates an added layer of protection for use in especially harsh settings. These can include:
  • Mining. Mining water can be highly acidic. A range of microorganisms in that water can create both sulfuric acid and hydrogen sulfide, both of which are highly corrosive.

  • Oil & gas. Corrosion has been estimated to cost the oil and gas industry – including exploration, production and refining – more than $1.3 billion every year, according to NACE International. These costs arise out of unscheduled plant shutdowns, along with lost production and high repair costs.

  • Transportation and infrastructure. Corrosion is a leading contributor to our current infrastructure woes. A study commissioned by the U.S. Federal Highway Administration estimates corrosion costs U.S. industry and business $276 billion per year.

  • Wastewater and water treatment plants. These facilities handle some of the most corrosive liquids and solids faced by any industrial environment. And they require a vast array of electric motors and pumps to keep up and running.

Where material strength is less critical, the same PVC coating can offer corrosion protection to rigid aluminum fittings and conduit. Aluminum is both non-sparking and non-magnetic, which makes it suitable in code-defined classified locations and in applications where electromagnetic and radio-frequency interference are concerns.
Photo courtesy of Calbond
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