Join 60,000+ competitive exam aspirants
or with email
Your Cart
SubtotalтВ╣0
TotalтВ╣0
Examoogle тАв User тАв info@examoogle.com тАв EE-2024-8821
Chapter 1 of 12 тАв Page 1 of 248ЁЯФТ Protected PDF тАв Watermarked
Join 60,000+ competitive exam aspirants
The metal conduits can be protected against corrosion by:
Galvanizing
Applying varnish
Applying oil
Wrapping adhesive tape
Galvanizing
Galvanizing is a process of coating steel or iron conduits with a thin layer of zinc to provide protection against corrosion. Zinc acts as a sacrificial anode, preventing the underlying metal from oxidizing even when the coating is slightly damaged.
Galvanizing is a process of coating steel or iron conduits with a thin layer of zinc to provide protection against corrosion. Zinc acts as a sacrificial anode, preventing the underlying metal from oxidizing even when the coating is slightly damaged.
ZnтЖТZn2++2eтИТ тАФ Oxidation reaction of zinc acting as a sacrificial anode.
The principle of galvanizing is based on electrochemical protection. Zinc has a higher electrode potential than iron (EZn0тАЛ=тИТ0.76V, EFe0тАЛ=тИТ0.44V), making it more reactive. It forms a protective oxide layer (ZnO) and a carbonate layer (ZnCO3тАЛ) that prevents atmospheric moisture and oxygen from reacting with the base metal conduit.
Galvanization is the most durable method for protecting conduits installed in outdoor or industrial environments.
The process is often performed via 'Hot-Dip' galvanizing, where metal is immersed in molten zinc.
It satisfies the durability requirements stipulated in Indian Standard (IS) codes for electrical wiring systems.
Zinc-rich coatings provide both a barrier and galvanic (cathodic) protection.
Long-term durability and low maintenance
Self-healing properties for minor scratches
Excellent resistance to environmental moisture and chemical vapors
Higher initial cost compared to enamel painting
Requires specialized equipment for hot-dip process
Cannot be used where zinc reactivity might interfere with chemical processes
External electrical conduit runs
Industrial plant wiring
Corrosive environments (chemical plants, coastal areas)
Varnish and oil are temporary solutions used for moving mechanical parts, not for structural electrical conduits.
Wrapping with adhesive tape may trap moisture if not applied with a perfect seal, potentially accelerating pitting corrosion.
Galvanizing is recognized by the National Electrical Code and IS 1239 for conduit protection.
A is correct тАФ Galvanizing provides a sacrificial zinc layer that prevents atmospheric corrosion of electrical conduits.
In competitive exams, always distinguish between temporary protection (grease/oil) and permanent structural protection (galvanizing/anodizing) for electrical equipment.