Before the piping enters the building, underground metallic piping must use what kind of fitting?

Before the piping enters the building, underground metallic piping must use what kind of fitting?

• A. Insulating (Dielectric)
• B. Copper sleeve
• C. Plastic coupling
• D. Stainless shield

Answer: (A)

Preventing galvanic corrosion at the transition from underground piping into the building is the main idea. When metal piping that’s buried in moisture-rich soil comes into contact with other metals inside the building, electrical currents can flow through the moisture and cause electrolysis, which corrodes the pipe over time. An insulating (dielectric) fitting creates a non-conductive barrier at that juncture, breaking the electrical path between the two metals and stopping this corrosion process. This type of fitting is specifically designed to join dissimilar metals or to separate the underground metal system from the interior piping, while still providing a secure, gas-rated seal. The other options don’t provide that electrical isolation in the same reliable way: a copper sleeve keeps metals electrically connected, so it doesn’t prevent galvanic action; a stainless shield doesn’t isolate the connection; and a plastic coupling might offer isolation but isn’t the standard, code-approved device for this transition in propane installations. So, using an insulating (dielectric) fitting is the proper choice to protect the piping system.

Preventing galvanic corrosion at the transition from underground piping into the building is the main idea. When metal piping that’s buried in moisture-rich soil comes into contact with other metals inside the building, electrical currents can flow through the moisture and cause electrolysis, which corrodes the pipe over time. An insulating (dielectric) fitting creates a non-conductive barrier at that juncture, breaking the electrical path between the two metals and stopping this corrosion process.

This type of fitting is specifically designed to join dissimilar metals or to separate the underground metal system from the interior piping, while still providing a secure, gas-rated seal. The other options don’t provide that electrical isolation in the same reliable way: a copper sleeve keeps metals electrically connected, so it doesn’t prevent galvanic action; a stainless shield doesn’t isolate the connection; and a plastic coupling might offer isolation but isn’t the standard, code-approved device for this transition in propane installations. So, using an insulating (dielectric) fitting is the proper choice to protect the piping system.