NEC Commercial Electrical Practice Test

What is the method used to protect steel or iron pipe grounding electrodes from corrosion?

1. Galvanizing

2. Painting

3. Enclosing in plastic

4. Using stainless steel

The correct answer is: Galvanizing

The method of galvanizing is used to protect steel or iron pipe grounding electrodes from corrosion. Galvanization involves coating the metal with a layer of zinc, which acts as a sacrificial anode. Zinc is more reactive than steel or iron in corrosive environments, meaning that it will corrode preferentially and protect the underlying metal. This electrochemical process significantly extends the lifespan of grounding electrodes, which are essential for safely dissipating electrical surges into the ground. While painting can provide a barrier against moisture and oxygen, it may not be sufficient in harsher environments, as paint can chip or wear off over time. Enclosing in plastic can offer protection as well, but this option is typically more relevant for insulated cables rather than metal pipes used as grounding electrodes. Using stainless steel is another corrosion-resistant option, but it is often more expensive and doesn't provide the same sacrificial protection that galvanized coatings do. Therefore, galvanizing remains the established method specifically for grounding electrode applications in order to mitigate corrosion effectively and reliably.