Arc Flash / Power Systems Studies Engineer

Ryan Mahoney

Why this role is hard · Ryan Mahoney

The real challenge is telling apart engineers who just run templates from those who actually understand the work. This role requires people who pay close attention to site conditions, share their findings without unnecessary jargon, and stand behind their math when outcomes change. We often confuse comfort with a modeling tool like ETAP for actual engineering judgment. A candidate who can script complex macros but cannot explain why bus impedance shifts during a retrofit will generate compliant paperwork that falls apart when reality hits. We need engineers who treat project assumptions as variables that change, not fixed inputs.

Core Evaluation

Critical questions for this role

The competency and attitude questions below are where the hiring decision is made. They run in the live interview rounds and are calibrated to the level selected above.

19 Competency Questions

1 of 19

  1. Discipline

    Grid Integration Compliance and Strategic Operations

  2. Job requirement

    Energy Storage Integration & Compliance

    Performs baseline BESS impact studies and documents compliance requirements for standard interconnection requests.

  3. Expected at Junior

    Aligns with the level's scope of executing standardized impact assessments and maintaining compliance documentation for routine interconnection workflows.

Interview round: Hiring Manager Technical: Power Systems Methodology

Describe a time you integrated battery storage parameters into a grid interconnection simulation. What steps did you take to finalize the model?

Positive indicators

  • Sources specifications from manufacturer data
  • Uses approved configuration templates
  • Follows compliance logging procedures
  • Documents all parameter selections
  • Conducts pre-submission validation

Negative indicators

  • Uses generic or outdated storage parameters
  • Deviates from approved templates
  • Fails to track compliance requirements
  • Leaves assumptions undocumented
  • Skips validation steps

14 Attitude Questions

1 of 14

Accountability Mindset

A consistent professional orientation toward owning decisions, work products, and outcomes by proactively identifying risks, transparently communicating limitations, and implementing corrective actions without deflection. In power systems engineering, it manifests as rigorous validation of technical assumptions, strict adherence to safety and compliance standards, and a commitment to resolving discrepancies between modeled predictions and field realities through structured feedback loops.

Interview round: Recruiter Screen: Role Alignment & Logistics

What is your process when you realize an input parameter used in your study was inaccurate after the initial simulation run?

Positive indicators

  • References established error-correction protocols
  • Updates model logs before proceeding to next steps
  • Validates corrected outputs against field data

Negative indicators

  • Continues with original parameters to save time
  • Fails to document input corrections for audit purposes
  • Shifts responsibility to data collection teams

Supporting Evaluation

How candidates earn the selection conversation

The goal is to reduce effort for everyone by collecting more useful signal before adding more interviews. Lightweight application prompts and structured screens help the panel focus live time on the candidates most likely to succeed.

Stage 1 · Application

Filter at the door

Runs the moment a candidate hits Submit. Disqualifying answers end the application; everything else is captured for review.

Knock-out Questions

1 of 2

Application Screen: Knock-out

Do you hold a current, active Professional Engineer (PE) license in the United States?

Yes
Qualifies
No
Auto-decline

Video-Response Questions

1 of 2

Application Screen: Video Response

Describe a situation where you had to present complex arc flash incident energy calculations or protective device coordination results to maintenance supervisors or project managers who lacked deep electrical engineering backgrounds. What specific steps did you take to ensure they understood the safety boundaries and PPE requirements, and how did you adjust your communication approach when you noticed confusion or pushback regarding the proposed hazard zones?

Candidate experience

REC
0:42 / 2:00
1Record
2Review
3Submit

Response time

2 min

Format

Recorded video

Stage 2 · Resume Screening

Read the resume against fixed criteria

Reviewers score every application that clears the door against the same criteria. Stronger reviews advance to live interviews; weaker ones are archived without further screening.

Resume Review Criteria

8 criteria
Demonstrated experience constructing and validating ETAP/SKM one-line diagrams using verified site measurements and equipment nameplate data.
Proven application of IEEE 1584 and NFPA 70E standards to calculate incident energy, fault currents, and generate compliant hazard labels.
Experience analyzing time-current curves to identify miscoordination and recommend relay adjustments for reliability and safety.
Evidence of coordinating with utility engineers and translating technical study results for maintenance and field operations teams.

Does the cover letter or personal statement convey clear relevance and familiarity with the job?

Does the resume indicate required academic credentials, relevant certifications, or necessary training?

Is the resume complete, well-organized, and free from formatting, spelling, and grammar mistakes?

Does the resume show relevant prior work experience?

Stage 3 · During Interviews

Where the hire is decided

Interview rounds use the competency and attitude questions outlined above, then add tests, work simulations, and presentations that reveal deeper evidence about how the candidate thinks and works.

Coding Test

1 of 2

Live Interview · Coding Test

Without AI

Implement the function using standard Python libraries. Handle missing or invalid values gracefully. Return a structured dictionary with calculated currents, compliance flags, and a brief summary.

Write a function to parse feeder data, calculate downstream fault current using standard impedance formulas, and flag equipment where available fault current exceeds interrupting rating. Handle missing/invalid values gracefully.

With AI

You may use AI tools to generate boilerplate, but you must explicitly design the validation logic, temperature derating, and audit trail. Explain why you accepted or rejected AI suggestions for the architecture.

Extend the provided skeleton to support dynamic utility data ingestion, implement temperature derating for conductor impedance per IEEE standards, and produce a structured audit log explaining calculation assumptions for regulatory review. AI will likely produce rigid scripts; you must justify your architectural choices for extensibility and compliance.

Response time

20 min

Positive indicators

  • Correct unit handling and impedance-to-fault-current conversion
  • Robust error handling for missing/NaN field data
  • Clear, readable structure with logical separation of validation and calculation
  • Accurate compliance flagging against interrupting ratings
  • Explicit temperature derating logic integrated into impedance calculation
  • Modular design separating data parsing, physics calculation, and compliance logging
  • Clear audit trail capturing assumptions, tolerances, and data gaps
  • Critical evaluation of AI output, rejecting hardcoded thresholds in favor of configurable parameters

Negative indicators

  • Hardcoding constants without explanation
  • Ignoring temperature or unit conversion impacts
  • Crashing on malformed input
  • Returning unstructured or ambiguous results
  • Accepting AI-generated monolithic scripts without modification
  • Missing derating or audit logging entirely
  • Brittle error handling that fails on schema drift
  • Inability to articulate why certain AI suggestions were unsafe for regulatory compliance

Presentation Prompt

Walk us through how you would approach reconciling discrepancies between legacy facility drawings and actual switchgear configurations during a site walkthrough, ensuring IEEE 1584 calculation boundaries remain accurate without overcomplicating the baseline model. Slides are optional; you can simply talk us through your reasoning and step-by-step methodology.

Format

approach-walkthrough · 20 min · ~2 hr prep

Audience

Senior engineering leadership and cross-functional safety stakeholders

What to prepare

  • A structured verbal outline of your problem framing, key assumptions, data validation steps, and trade-off considerations
  • Optional: 1-2 hours reviewing relevant IEEE 1584 guidelines or past project contexts to ground your narrative

Deliverables

  • A structured verbal walkthrough of your reasoning process
  • Clarifying questions to define the problem constraints
  • A discussion of trade-offs, validation steps, and escalation criteria

Ground rules

  • Focus on your reasoning process and decision framework rather than producing a final deliverable
  • Use only hypothetical scenarios or anonymized past experiences you are permitted to share
  • Slides are optional; a conversational walkthrough is fully acceptable

Scoring anchors

Exceeds
Frames the problem comprehensively, proactively identifies hidden risks, demonstrates rigorous validation steps, and clearly articulates trade-offs with actionable escalation criteria.
Meets
Presents a logical, standards-aligned approach, acknowledges key constraints, and outlines a reasonable validation and communication process.
Below
Offers a fragmented or purely theoretical solution, overlooks critical safety/regulatory constraints, and struggles to explain how assumptions would be verified or communicated.

Response time

20 min

Positive indicators

  • Asks high-information clarifying questions to define constraints before proposing a solution
  • Explicitly surfaces assumptions and explains how they would validate them with field data or OEM specs
  • Walks through a structured methodology that balances regulatory compliance with operational realities
  • Identifies key trade-offs and articulates clear criteria for when to escalate or halt work

Negative indicators

  • Jumps directly to a technical solution without framing the problem or acknowledging constraints
  • Ignores safety or regulatory boundaries in favor of schedule or cost pressures
  • Fails to articulate how they would validate assumptions or reconcile conflicting data sources
  • Communicates in overly dense jargon without translating implications for cross-functional stakeholders

Work Simulation Scenario

Scenario. You are tasked with initiating an arc flash and short-circuit study for a newly acquired transit depot. The facility has legacy single-line drawings from 1998, but recent field walkthroughs by maintenance crews indicate several undocumented cable reroutes and replaced switchgear. You have 3 weeks to deliver a baseline ETAP model that will feed into the quarterly safety audit. How do you approach this?

Problem to solve. Construct a reliable field-to-model translation strategy that reconciles undocumented changes with legacy drawings while establishing clear boundaries for data validation and model accuracy.

Format

discovery-interview · 40 min · ~2 hr prep

Success criteria

  • Identify critical data gaps and prioritize field verification steps
  • Define clear assumptions and escalation triggers for discrepancies
  • Align model validation with maintenance crew capabilities and safety constraints

What to review beforehand

  • Basic ETAP/SKM modeling principles
  • IEEE 1584 and NFPA 70E fundamentals for arc flash studies
  • Standard field data collection protocols for electrical infrastructure

Ground rules

  • This is a discovery conversation. Ask clarifying questions before proposing solutions.
  • The interviewer will answer honestly but will not volunteer information.
  • Focus on your process, assumptions, and how you handle ambiguity.

Roles in scenario

Informed Partner (Senior Field Technician & Facility Manager) (informed_partner, played by cross_functional)

Motivation. Ensure the study model reflects actual field conditions without causing unnecessary downtime or safety risks during data collection.

Constraints

  • Limited access to energized equipment
  • Maintenance crew availability only during off-peak shifts
  • Legacy drawings are incomplete and lack revision history

Tensions to introduce

  • Some switchgear nameplates are obscured or missing
  • Maintenance crew is hesitant to perform certain measurements due to perceived arc flash risks
  • Facility manager wants the model delivered quickly to secure capital funding

In-character guidance

  • Answer questions directly but concisely
  • Share operational realities only when asked
  • Validate candidate's assumptions about safety protocols

Do not

  • Do not volunteer missing data unless explicitly asked
  • Do not suggest specific ETAP modeling techniques
  • Do not escalate hostility or rush the candidate

Scoring anchors

Exceeds
Candidate systematically surfaces hidden assumptions, constructs a rigorous validation framework, explicitly defines escalation triggers, and demonstrates strong professional boundary-setting around safety and data integrity.
Meets
Candidate asks relevant clarifying questions, proposes a structured approach, acknowledges key constraints, and identifies reasonable escalation paths for safety or data discrepancies.
Below
Candidate makes unsupported assumptions, proposes unsafe or impractical validation steps, fails to define escalation boundaries, or defers to schedule pressures without evaluating safety impact.

Response time

40 min

Positive indicators

  • Asks targeted questions to identify specific data gaps between legacy drawings and field conditions
  • Proposes a structured validation sequence prioritizing safety-critical equipment first
  • Explicitly defines escalation triggers for undocumented discrepancies before committing to model assumptions
  • Aligns field data collection timelines with maintenance crew availability and safety constraints

Negative indicators

  • Assumes legacy drawings are accurate without proposing verification steps
  • Proposes invasive or unsafe data collection methods without consulting field staff
  • Fails to establish clear boundaries for model accuracy or escalation thresholds
  • Overlooks maintenance crew constraints and proposes unrealistic data acquisition schedules

Progression Framework

This table shows how competencies evolve across experience levels. Each cell shows competency at that level.

Grid Integration Compliance and Strategic Operations

4 competencies

CompetencyJuniorMidSenior
Energy Storage Integration & Compliance

Performs baseline BESS impact studies and documents compliance requirements for standard interconnection requests.

Designs advanced storage integration scenarios, optimizes charge/discharge strategies for grid support, and resolves complex compliance deviations.

Sets enterprise BESS integration standards, leads regulatory engagement on emerging storage safety codes, and approves high-impact grid tie designs.

Operational Incident Response & Risk Analytics

Documents operational incidents, assists in data collection for root cause analysis, and runs basic risk screening models.

Leads post-incident technical investigations, develops corrective action plans, and implements advanced probabilistic risk assessments.

Architects enterprise incident response frameworks, establishes risk tolerance thresholds, and directs strategic resilience planning across the network.

Regulatory Compliance & Standards Management

Tracks regulatory updates, maintains compliance checklists, and supports documentation for standard audits.

Interprets complex regulatory changes, develops compliance implementation roadmaps, and coordinates cross-functional audit preparations.

Represents the organization in standards committees, authors internal compliance directives, and provides final technical sign-off on regulatory adherence.

Strategic Network Planning & Optimization

Supports data gathering for capacity forecasts, runs baseline optimization scenarios, and prepares planning reports.

Develops multi-year network expansion strategies, evaluates trade-offs between reliability and cost, and leads stakeholder alignment workshops.

Defines enterprise planning horizons and investment criteria, authors strategic network roadmaps, and advises executive leadership on long-term infrastructure resilience.

Power Systems Modeling and Safety Analysis

4 competencies

CompetencyJuniorMidSenior
Arc Flash Hazard Assessment & Mitigation

Applies standard calculation methods to determine incident energy levels and generates preliminary safety labels.

Evaluates mitigation alternatives, coordinates protective device settings to reduce hazard levels, and validates compliance with safety standards.

Develops site-wide arc flash mitigation programs, authors enterprise safety protocols, and provides technical arbitration on complex hazard scenarios.

Field Data Acquisition & System Modeling

Executes standardized field data collection routines and populates baseline system models using established templates.

Validates complex multi-site datasets, resolves data inconsistencies, and optimizes model topology for accuracy and computational efficiency.

Defines enterprise data acquisition standards, validates model integrity across diverse network configurations, and mentors teams on advanced modeling techniques.

Load Flow & Short Circuit Analysis

Runs standard load flow and short circuit simulations using predefined scenarios and interprets baseline outputs.

Designs complex fault scenarios, analyzes contingency impacts, and recommends system modifications to address thermal or voltage violations.

Establishes simulation methodologies for extreme fault conditions, validates results against utility standards, and authorizes critical equipment ratings.

Transit Electrification Network Studies

Supports modeling of charging load profiles and basic traction power network configurations under supervision.

Leads integrated transit network simulations, optimizes charging schedules, and resolves grid-tie capacity constraints.

Architects comprehensive electrification study frameworks, establishes transit-specific safety and performance benchmarks, and advises on capital planning.