BGE Material Selection & Properties 2

Question 1

Which conductor material is most commonly used for overhead transmission lines due to its high strength-to-weight ratio?

Accepted Answer

ACSR (Aluminum Conductor Steel Reinforced)

Answer

ACSR combines aluminum's conductivity with a steel core for tensile strength, making it ideal for long-span overhead transmission lines.

Question 2

What is the primary reason polyethylene (PE) piping is preferred over steel for new underground natural gas distribution mains?

Accepted Answer

Corrosion resistance and ease of installation

Answer

Polyethylene does not corrode, requires no cathodic protection, and can be fused in the field, significantly reducing long-term maintenance costs.

Question 3

A utility crew needs to connect a copper busbar to an aluminum conductor. What material concern must be addressed?

Accepted Answer

Galvanic corrosion at the bimetallic junction

Answer

Copper and aluminum have different electrochemical potentials; direct contact in the presence of moisture causes galvanic corrosion that degrades the connection.

Question 4

Which insulation class is rated for continuous operation at 90°C for underground residential distribution (URD) cables?

Accepted Answer

Class C (90°C) — XLPE or EPR

Answer

Cross-linked polyethylene (XLPE) and ethylene propylene rubber (EPR) are standard 90°C-rated insulations used in URD cable installations.

Question 5

For gas service risers transitioning from underground PE to aboveground steel, what fitting is required at the transition point?

Accepted Answer

Anodeless riser or PE-to-steel transition fitting

Answer

An anodeless riser or factory-made PE-to-steel transition fitting safely joins the two incompatible materials while maintaining pressure integrity and corrosion protection.

(BGE) Baltimore Gas and Electric Practice Test

(BGE) Baltimore Gas and Electric Practice Test

BGE Material Selection & Properties 2