BGE Material Selection & Properties 3

Question 1

Which material property determines how much a metal expands when heated, and why is it critical for pipeline design?

Accepted Answer

Coefficient of thermal expansion

Answer

The coefficient of thermal expansion dictates how much a pipe grows or contracts with temperature changes; expansion loops and offsets must accommodate this movement to prevent stress failures.

Question 2

A BGE technician is selecting grounding electrodes for a new substation. Which material offers the best long-term corrosion resistance for buried ground rods in Maryland's soil?

Accepted Answer

Bare copper-clad steel

Answer

Copper-clad steel rods combine steel's mechanical strength with copper's excellent corrosion resistance in soil, making them the industry-standard choice for grounding electrodes.

Question 3

What is the maximum allowable operating pressure (MAOP) classification for PE 4710 gas distribution pipe in a typical residential distribution system?

Accepted Answer

Up to 100 psi for medium-density PE in distribution class

Answer

PE 4710 pipe used in distribution-class systems is generally rated up to 100 psi, sufficient for residential and light commercial natural gas service.

Question 4

Which transformer insulation system uses mineral oil as both a coolant and a dielectric medium?

Accepted Answer

Liquid-immersed oil-filled transformer

Answer

Liquid-immersed (oil-filled) transformers circulate mineral oil to dissipate heat and provide dielectric insulation between windings and the tank.

Question 5

A gas line crossing a river requires a casing pipe. What material is specified in DOT regulations for the carrier pipe inside the casing?

Accepted Answer

Standard-weight carbon steel with external coating and cathodic protection

Answer

DOT 49 CFR Part 192 requires steel carrier pipe with external corrosion coating and cathodic protection for crossings through casings under water bodies.

(BGE) Baltimore Gas and Electric Practice Test

(BGE) Baltimore Gas and Electric Practice Test

BGE Material Selection & Properties 3