Practice Test Geeks(BGE) Baltimore Gas and Electric Practice Test
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Material Selection & Properties Flashcards

7 cards from real BGE practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

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

    Answer: ACSR (Aluminum Conductor Steel Reinforced)

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

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

    Answer: Corrosion resistance and ease of installation

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

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

    Answer: Galvanic corrosion at the bimetallic junction

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

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

    Answer: Class C (90°C) — XLPE or EPR

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

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

    Answer: Anodeless riser or PE-to-steel transition fitting

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

  6. What property of SF6 (sulfur hexafluoride) gas makes it valuable in high-voltage switchgear?

    Answer: Superior dielectric strength — about 2.5× that of air

    SF6's exceptional dielectric strength allows switchgear to interrupt fault currents and withstand high voltages in a much smaller physical footprint than air-insulated equipment.

  7. When selecting wire for a motor control center (MCC) operating at 600V, what minimum insulation voltage rating is typically required by the NEC?

    Answer: 600V rated wire (e.g., THWN-2 or XHHW-2)

    The NEC requires conductors in 600V systems to have insulation rated for at least 600V; THWN-2 and XHHW-2 are common choices that also handle moisture.