KCW

Question 1

Walk me through your process for doing a QA/QC review on a Pepco distribution design

Answer 1

S – At Pepco, reliability issues on several URD feeders were traced back to inconsistent design practices and outdated components.
T – I was responsible for reviewing feeder packages and confirming compliance with Pepco and NEC/NESC standards.
A – I followed a structured QA checklist: I verified conductor sizing, insulation ratings, trench/conduit requirements, grounding/bonding, transformer loading, and protection coordination. I compared each sheet against Pepco construction standards, ensuring clearances, cable pull limits, and device placements aligned with the latest spec revisions.
R – My reviews flagged early errors like undersized fuses and improper grounding layouts, preventing potential field issues and reducing repeat outages on those circuits.

Question 2

How do you verify that a design meets Pepco, DDOT, NEC, and NESC requirements?”

Answer 2

S – On a URD reliability improvement project, some proposed designs didn’t align with both Pepco specs and DDOT right-of-way rules.
T – I needed to confirm that the design met all overlapping jurisdictional requirements.
A – I cross-checked the design against Pepco’s U-Series construction standards, DDOT’s utility accommodation requirements, and NEC/NESC criteria for trench depth, clearance, grounding, and equipment spacing. I validated each conflict point and documented required adjustments for the designers.
R – The final package passed Pepco QA on the first submission and avoided a two-week resubmission delay with DDOT.

Question 3

How do you prioritize feeder upgrades using SAIDI/SAIFI/CAIDI data?

Answer 3

I analyze which feeders have the highest outage frequency and duration, then correlate those with asset condition and outage cause categories. Feeders with high SAIFI or CAIDI values and aging assets rise to the top of the list. I also look for repeat outages in the same locations to target proactive replacements.

Question 4

Explain the difference between URD and Comprehensive Feeders.

Answer 4

URD feeders are entirely underground and usually fail due to insulation breakdown, cable faults, or bad elbows. Comprehensive feeders combine overhead and underground sections, so their failure modes include tree contacts, weather events, splices, and equipment failures across both environments. The maintenance and reliability considerations are different for each type.

Question 5

Describe your approach to outage root-cause analysis.

Answer 5

I look at OMS and SCADA logs, switching operations, and historical outage patterns to isolate the failure mechanism. Then I review asset age, loading, and any environmental contributors. Once I identify the cause — whether it’s a cable, transformer, splice, or equipment issue — I recommend a corrective action like replacement, sectionalizing, or protection adjustments.

Question 6

How do you evaluate transformer loading and sizing?

Answer 6

I compare the transformer’s nameplate rating against peak loads, consider seasonal variations, and check thermal and overload limits. I ensure voltage drop is acceptable and the transformer can handle inrush, fault currents, and worst-case conditions. If a transformer is near its limits, I recommend upsizing or load balancing.

Question 7

What is your experience with grounding and bonding reviews?

Answer 7

I validate that grounding follows NEC/NESC and Pepco standards. That includes confirming neutral bonding intervals, verifying ground rod installation, ensuring equipment grounding meets impedance requirements, and checking clear paths for fault current. I look for consistent and code-compliant grounding layouts across the entire design.

Question 8

How do you evaluate voltage drop or ampacity in a design?

Answer 8

I calculate expected voltage drop using conductor resistance and current levels, then compare it to allowable limits. For ampacity, I reference Pepco’s tables and verify that conductor size, insulation, and temperature ratings support the expected load under normal and contingency conditions.

Question 9

Tell me about a technical error you’ve caught during a review.

Answer 9

I’ve caught issues such as incorrect component ratings, grounding inconsistencies, and load levels that exceeded equipment limits. When I find a discrepancy, I validate it with the applicable standard and give the designer a clear correction with justification, so the design stays both safe and compliant.

Question 10

How do you handle disagreements in technical reviews?

Answer 10

I lead with data. I explain my reasoning clearly, reference the applicable standard, and walk through the implications of not correcting the issue. I’m collaborative — if the designer has another perspective, I’m open to reviewing their evidence. The goal is always accuracy and safety, not winning the argument.

Question 11

How do you ensure electrical design packages comply with Pepco, DDOT, and local jurisdiction standards?

Answer 11

I cross-check every design element against Pepco distribution standards, DDOT permitting requirements, and local electrical codes. I use checklists I’ve built from QA findings and verify conductor sizing, protection coordination, civil/structural constraints, and as-built accuracy. I also review vendor/manufacturer specs to ensure compatibility with Pepco-approved equipment.

Question 12

What steps do you take when you find a major discrepancy in a design package?

Answer 12

I document the discrepancy, trace it back to its source (calculation error, modeling mismatch, outdated standard, etc.), and notify the design engineer with a recommended correction. I verify the correction, update the QA log, and ensure downstream documents—BOMs, schematics, cable schedules, and drawings—are updated to maintain consistency.

Question 13

How do you validate that protection and coordination studies are accurate?

Answer 13

I review relay settings, time-current curves, and feeder characteristics against Pepco coordination requirements. I verify that protective devices isolate faults without impacting upstream reliability metrics. My reliability engineering background helps me check device performance against SAIDI, SAIFI, and CAIDI improvement goals.

Question 14

What is your approach to reviewing underground distribution (URD) designs for quality?

Answer 14

I check trench layouts, conduit fill, duct bank thermal performance, splice locations, and cable ampacity. I confirm that the design follows Pepco’s URD standards, respects minimum separation from other utilities, and accounts for load growth. I also verify grounding, bonding, and manhole configurations for safety and maintainability.