Exam prep for NABCEP (United States)

Regional differences that matter

United States — NEC

NFPA 70E boundaries, OSHA fall protection, NEC rapid shutdown. Approach boundaries and arc-flash PPE categories are examined against NFPA 70E, fall protection against OSHA 1926 Subpart M, and rapid shutdown plus disconnect accessibility against NEC 690.12 and 690.13. The point candidates lose marks on: rapid shutdown limits conductor voltage inside the array boundary, it does not isolate — residual voltage must still be verified at the point of work.

Cluster self-check — one principle, three exam styles

1. United States — NECQuestion 1

   Under NFPA 70E, the arc-flash boundary is established by:

   Nominal system voltageIncident energy — available fault current and clearing timeConductor insulation ratingThe restricted approach boundary
2. South Africa — SANS / CoCQuestion 2

   Under the OHS Act Electrical Installation Regulations, who may issue the Certificate of Compliance for a PV installation?

   Any qualified installerA registered personThe system ownerThe inverter manufacturer's agent
3. Kenya — EPRA / NITAQuestion 3

   An EPRA T1 licence holder is asked to isolate and switch a grid-tie system unsupervised. The correct response is:

   Proceed if they feel competentDecline and escalate — the work sits outside the licence classProceed with the homeowner present as a witnessProceed but do not sign anything
4. United States — NECQuestion 4

   NEC 690.12 rapid shutdown has operated. The conductors inside the array boundary are:

   Isolated and safe to handleLimited in voltage, but must still be verified dead before workGrounded automaticallyBelow 1 V by definition
5. South Africa — SANS / CoCQuestion 5

   SANS-aligned practice for a battery room in a dwelling requires, above all:

   A locked door onlyVentilation and segregation appropriate to the chemistry, with the evidence recordedA fire blanket on the wallBatteries mounted at floor level
6. Kenya — EPRA / NITAQuestion 6

   On a Kenyan off-grid site with a backup generator, which source is most often missed during isolation?

   The arrayThe generator back-feeding through the ATS the moment the mains dropThe batteryThe inverter DC link
7. United States — NECQuestion 7

   OSHA 1926 Subpart M is satisfied by clipping a lanyard to which of the following?

   A PV mounting railA fascia-mounted bracketAn anchor fixed into structure and rated for arrest loadsA roof-mounted conduit run
8. South Africa — SANS / CoCQuestion 8

   A fall is arrested and the technician hangs conscious in the harness. The fall-protection plan must provide:

   An incident formA pre-planned rescue executed within minutes because of suspension traumaA spare harnessA second anchor
9. Kenya — EPRA / NITAQuestion 9

   EPRA expects an incident where a technician stopped work due to unprovable isolation to be:

   Left unrecorded — no work was doneDocumented with the reason, the evidence and the condition that would allow resumptionReported only if someone was injuredRecorded verbally to the supervisor
10. United States — NECQuestion 10

    Why can a battery DC bus demand a higher PPE category than the AC switchboard on the same site?

    Its voltage is higherVery high available fault current with no fast upstream protective deviceDC gloves are rated differentlyBatteries are unearthed
11. South Africa — SANS / CoCQuestion 11

    A lithium cabinet is hot, smells of solvent and shows a BMS temperature alarm. The correct action is:

    Open the cabinet and identify the hot moduleEvacuate, keep clear, call the fire service with chemistry and capacity, isolate only from a safe positionCarry the pack outsideDischarge a CO2 extinguisher into the vents
12. Kenya — EPRA / NITAQuestion 12

    Electrolyte from a flooded bank splashes a technician's eye. The correct first action is:

    Neutralise with bicarbonate solutionFlush with clean water for at least 15 minutes while heading for medical helpCover the eye and drive to the clinicRinse briefly and continue work

Regional differences that matter

United States — NEC

Listed equipment. Equipment must be listed and labelled for the application; rapid-shutdown-capable equipment is effectively mandatory on most rooftops.

Regional differences that matter

United States — NEC

NEC 690.7 voltage calculation. Maximum system voltage is calculated using the record low ambient temperature and the module temperature coefficient, or the NEC correction table.

Regional differences that matter

United States — NEC

Design is verified, not authored, in the field. PVIP-level work verifies a stamped design against NEC limits and equipment listings rather than originating it.

Regional differences that matter

United States — NEC

Fire setbacks and pathways. Rooftop setbacks and access pathways are enforced by the fire code and inspected at final.

Regional differences that matter

United States — NEC

NEC Article 690 and 705 — grounding, bonding and rapid shutdown. NEC 690 and 705 drive rapid shutdown, equipment grounding conductor sizing and array bonding, plus the interconnection and busbar-loading rules. Candidates are expected to separate functional (system) grounding from equipment grounding, use listed rapid-shutdown equipment, and specify the correct SPD type. Inspection routinely checks continuity of the equipment grounding path — and rapid shutdown limits voltage inside the array boundary, it does not isolate.

Cluster self-check — one principle, three exam styles

1. United States — NECQuestion 1

   On a US rooftop PV system, which conductor is primarily checked for continuity when the equipment grounding path is inspected?

   The grounded (neutral) conductorThe equipment grounding conductor from array frames back to the main bonding pointThe functional-earth conductor inside the inverterThe earth electrode conductor only
2. South Africa — SANS / CoCQuestion 2

   Under SANS 10142-1 practice, why does equipotential bonding of the array frame matter for the Certificate of Compliance?

   It improves yieldIt removes touch potential between simultaneously accessible metal parts, and the registered person must verify and record itIt reduces volt dropIt replaces the need for an earth electrode
3. Kenya — EPRA / NITAQuestion 3

   A hybrid system in Kenya shows no visible earth connection at the battery enclosure. The main risk is:

   Reduced battery capacityExposed metalwork can reach a dangerous potential during a fault or surge, with no path for the surge the SPDs divertSlower chargingInverter over-voltage trips
4. United States — NECQuestion 4

   Which device is intended to limit overvoltage on the DC side from nearby lightning activity?

   The string fuseA DC-side surge protective deviceThe DC isolatorThe rapid-shutdown initiator
5. Kenya — EPRA / NITAQuestion 5

   String fuses are primarily intended to protect against which condition?

   Overload of the string they are fitted inReverse back-feed from the other parallel strings into a faulted stringLightning strikeInverter DC-link failure
6. South Africa — SANS / CoCQuestion 6

   An array is fed by two parallel strings, module maximum series fuse rating 20 A. The usual correct position is:

   Fit 25 A string fusesString fusing is generally not required; the module series fuse rating covers the two-string back-feedFit 30 A fuses for marginFit AC-rated fuse holders
7. United States — NECQuestion 7

   NEC 690.12 rapid shutdown has operated. The conductors inside the array boundary are:

   Isolated and safe to handleVoltage-limited, and still require prove-dead verification at the point of workAutomatically bonded to earthPhysically disconnected at each module
8. South Africa — SANS / CoCQuestion 8

   A conductor rated in free air at 30 °C is installed in conduit on a hot roof with three other circuits. Its usable capacity is closest to:

   UnchangedAbout half the free-air rating once temperature and grouping derating are appliedAbout 90 %Higher, because the conduit protects it
9. Kenya — EPRA / NITAQuestion 9

   A 60 m DC run performs slightly below expectation every day with no fault codes. The most likely cause is:

   A failing moduleVolt drop over the long runInverter firmwareSoiling only
10. United States — NECQuestion 10

    An AC-rated switch has been used as the array DC isolator. The problem is:

    It costs moreDC has no zero crossing, so the device cannot reliably extinguish the arcIt cannot carry the currentIt has the wrong terminal size
11. South Africa — SANS / CoCQuestion 11

    An SPD is installed with 900 mm connecting leads. The consequence is:

    No effect — length does not matterLead inductance raises the let-through voltage and largely defeats the deviceIt clamps at a lower voltageIt becomes a Type 1 device
12. Kenya — EPRA / NITAQuestion 12

    Before energisation, which pair of measurements best evidences the earthing and protection package?

    Open-circuit voltage and inverter efficiencyEarthing continuity from the furthest frame to the main earthing terminal, and earth electrode resistance — both recorded with instrument and dateAmbient temperature and irradianceCable colour and label placement

Regional differences that matter

United States — NEC

Permit final, rapid shutdown and permission to operate. Commissioning is tied to the permit final inspection and the utility interconnection process. The emphasis at inspection is rapid-shutdown verification, equipment grounding continuity, correct labelling and the manufacturer's start-up sequence. Test records may be requested by the AHJ or the utility before permission to operate is granted, so the values — not just the pass — need to exist.

Cluster self-check — one principle, three exam styles

1. United States — NECQuestion 1

   Before enabling a grid-tied inverter on a US installation, which verification is most directly tied to rapid-shutdown readiness?

   Open-circuit voltage of each stringOperation of the rapid-shutdown initiator with correct labelling at the disconnectBattery state of chargeMonitoring portal registration
2. South Africa — SANS / CoCQuestion 2

   Under SANS 10142-1 practice, which test result is commonly required as evidence supporting a Certificate of Compliance?

   Inverter efficiency from the datasheetMeasured earth continuity and insulation resistance, recorded with instrument and datePeak output on the day of handoverThe client's signature alone
3. Kenya — EPRA / NITAQuestion 3

   Which document is most appropriate to hand to the client after successful commissioning of a residential hybrid in Kenya?

   The installer's internal job sheetA commissioning and handover pack with test results, as-built information, settings and user guidanceThe module warranty onlyA verbal explanation of shutdown
4. United States — NECQuestion 4

   A measured insulation resistance on a DC string is significantly below the expected range. The correct immediate action is:

   Energise and monitor from the portalDo not energise; split the array and isolate the section causing the low readingRepeat at a lower test voltage until it passesRecord it and hand over with a note
5. South Africa — SANS / CoCQuestion 5

   Polarity on one string is reversed. If the system is energised anyway, the main risk is:

   Slightly reduced yieldThe correct strings drive current backwards through the reversed string, with real arcing and equipment damage potentialA monitoring error onlyNothing until the next service
6. Kenya — EPRA / NITAQuestion 6

   Why is the AC side energised before the DC side at first start-up?

   It charges the battery fasterThe inverter needs a valid grid reference and an export path before the array's energy is appliedModule warranty requires itThe order does not matter
7. United States — NECQuestion 7

   Two identical strings read 742 V and 693 V open-circuit at the same moment. The most likely cause is:

   Normal manufacturing toleranceA bypassed module or an open connector in the second stringAn inverter MPPT faultAn insulation fault
8. South Africa — SANS / CoCQuestion 8

   Insulation resistance must be measured with the inverter DC input disconnected because:

   It gives a higher readingThe applied test voltage can destroy inverter input circuitry, and the array must be under your controlThe inverter blocks the measurementIt is only a paperwork convention
9. Kenya — EPRA / NITAQuestion 9

   A hybrid drops all loads when the grid is deliberately removed during commissioning. The most likely cause is:

   Failed battery cellsLoads wired to the non-essential side, or backup mode not configuredLow insulation resistanceReversed string polarity
10. United States — NECQuestion 10

    A two-MPPT system produces almost exactly half its condition-corrected expectation at commissioning. The first check is:

    Order a replacement inverterCompare per-MPPT values — one input is likely contributing nothingClean the arrayRaise a module warranty claim
11. South Africa — SANS / CoCQuestion 11

    The difference between installation testing and ongoing performance monitoring is best described as:

    They are the same activityTesting proves the installation on the day; monitoring watches the trend over timeTesting is optional where monitoring existsMonitoring replaces the need for a commissioning record
12. Kenya — EPRA / NITAQuestion 12

    Which pair of records makes a commissioning result defensible a year later?

    A pass tick and the client's signatureThe measured value with its instrument, test voltage or lead resistance, and the date it was takenA photograph of the array and the inverter modelThe installer's invoice and the warranty card

Regional differences that matter

United States — NEC

Permit, inspection and warranty trail. Diagnosis often runs under permit, inspection and manufacturer-warranty constraints. Findings must survive a warranty claim and an inspector's review, so listed equipment, correct rapid-shutdown behaviour and documented measurements matter as much as the repair. Rapid shutdown limits voltage inside the array boundary — it is not isolation, and prove-dead before opening enclosures remains non-negotiable.

Cluster self-check — one principle, three exam styles

1. United States — NECQuestion 1

   A string shows near-zero current while adjacent strings are producing. After safe isolation, what is the best first measurement?

   Insulation resistance of the whole arrayOpen-circuit voltage of the affected string, compared against its neighbours at the same momentAC voltage at the service panelBattery state of charge
2. Kenya — EPRA / NITAQuestion 2

   An inverter repeatedly trips on over-frequency. Which category of cause should you investigate first?

   Inverter hardware failureSupply stability — grid or generator — and the configured grid profileModule degradationArray insulation resistance
3. South Africa — SANS / CoCQuestion 3

   Under SANS and CoC-oriented practice, why does recording the diagnostic steps and the final resolution matter?

   It lengthens the invoiceIt is the evidence behind compliance and quality claims, and the baseline the next technician works fromIt is only needed for new installationsIt replaces the need to measure
4. United States — NECQuestion 4

   A hybrid system logs battery protection events on high temperature. What is a sensible immediate action?

   Raise the temperature threshold so the system keeps runningRemove charge and discharge demand, let the pack cool, and establish why it is hotReplace the battery moduleIncrease charge current to balance the cells
5. South Africa — SANS / CoCQuestion 5

   Which step must come before opening a combiner or battery enclosure for diagnosis?

   Photographing the fault codeIsolation established and dead proved at the point of work with a proved testerContacting the manufacturerConfirming the warranty status
6. Kenya — EPRA / NITAQuestion 6

   An inverter reports an isolation fault every morning that clears by mid-morning after overnight rain. The likely cause is:

   Grid over-voltageMoisture ingress in a connector or damaged cable jacketA failed MPPT stageBattery imbalance
7. United States — NECQuestion 7

   The monitoring portal shows no data since yesterday, but the inverter display shows normal production. The correct conclusion is:

   The system has been offlineA communication-path fault: gateway, network or sensor wiringThe array has failedThe meter is faulty and must be replaced
8. South Africa — SANS / CoCQuestion 8

   Production cuts out around midday and returns in the afternoon; measured AC at the inverter terminals during the cut-out is 253 V. The first line of investigation is:

   Replace the inverterGrid voltage rise, including the site AC run — measure at the terminals and at the originClean the arrayReduce the battery reserve
9. Kenya — EPRA / NITAQuestion 9

   You have two credible hypotheses for a fault. The measurement worth taking first is the one that:

   Is quickestWould give a different result depending on which hypothesis is trueUses the most advanced instrumentProduces the best number for the report
10. United States — NECQuestion 10

    During a maintenance visit, the correct approach to fastener torque is to:

    Re-torque every accessible fastenerSample against the original torque marks and act on what has movedTighten by feelSkip torque once the system is commissioned
11. South Africa — SANS / CoCQuestion 11

    A structured diagnosis has run twice without moving closer to a cause, and the next step needs equipment access you are not authorised for. The professional action is:

    Replace the most likely componentEscalate with a clean evidence pack — symptom, measurements, what was ruled out and howClose the call as no fault foundReset the system to factory defaults
12. Kenya — EPRA / NITAQuestion 12

    Why are healthy findings, not just defects, recorded at a maintenance visit?

    To make the report longerSo the next visit has a comparable baseline and degradation shows up as a trendBecause clients pay per lineTo satisfy a page-count requirement

Regional differences that matter

United States — NEC

Permit, inspection, interconnection and owner pack. A permit package, final inspection records, manufacturer warranties, rapid-shutdown information and owner operating guidance are commonly expected. Documentation supports both code compliance at inspection and the warranty position afterwards. Utility interconnection approval is a separate, named-party process.

Cluster self-check — one principle, three exam styles

1. South Africa — SANS / CoCQuestion 1

   Which document is most specifically associated with formal electrical compliance sign-off in South Africa?

   The PV GreenCard checklistThe Certificate of Compliance issued by a registered personThe commissioning production baselineThe equipment warranty registration
2. Kenya — EPRA / NITAQuestion 2

   A client in Kenya asks what they should keep after installation. Which items are most important?

   Brochures and the crew's phone numbersAs-built and string schedule, test records, equipment list with serials, settings record, and shutdown and maintenance guidanceThe invoice onlyA photograph of the finished array
3. United States — NECQuestion 3

   Why should as-built information be updated if the installed string layout differs from the original design?

   To keep the drawing tidyBecause Voc expectations, fault diagnosis and inverter-window checks are all read from the as-built — a stale drawing sends the next technician to the wrong conclusionBecause the designer bills for revisionsIt should not be; the design is contractual
4. United States — NECQuestion 4

   In a US residential job, which records are most relevant at final inspection?

   Marketing brochures and monitoring screenshotsThe permit plan set, installed-state labelling including rapid-shutdown information, and evidence the installation matches the approved designInternal timesheetsThe battery manufacturer's press release
5. South Africa — SANS / CoCQuestion 5

   What is the main risk of handing over a system with no recorded test results?

   The folder looks thinThere is no evidence of the condition the system was left in, so later faults, warranty claims and compliance questions default against the installerThe inverter will not startMonitoring will not register
6. Kenya — EPRA / NITAQuestion 6

   A T2-licensed technician completes a grid-tied export installation. What does the record require?

   Recording it under T2 anywayEnsuring the responsible person named on the record holds the class the work falls underLeaving the class field blankRecording it as maintenance
7. South Africa — SANS / CoCQuestion 7

   You installed the system but are not a registered person. What do you tell the client about the CoC?

   That you will issue it once paidThat a registered person inspects and issues it, and that you supply the as-built, test results and settings record they needThat the manufacturer issues itThat it is optional for PV
8. United States — NECQuestion 8

   Which record best supports a future warranty claim?

   A photo of the finished arrayEquipment serials with install and commissioning dates, plus registration confirmationsThe client's signature on the invoiceA brochure for the inverter
9. Kenya — EPRA / NITAQuestion 9

   Which commissioning production record is actually usable as a baseline?

   'System producing well'A measured output figure with the irradiance, temperature and time it was takenThe nameplate ratingThe best figure seen in the first week
10. South Africa — SANS / CoCQuestion 10

    Why are inverter grid profile, export limit and firmware version part of the handover pack?

    They interest the manufacturer onlyBecause settings determine grid-compliance behaviour, and unrecorded settings cannot be audited or restored after a firmware update or board replacementTo lengthen the documentThey are not part of the pack
11. United States — NECQuestion 11

    Which handover statement is safe and accurate?

    'Your bill will go to zero''Expect this seasonal shape across the year; here is the shutdown procedure, and here are the recorded test results with their dates''It will make its 6.6 kW rating on sunny days''Don't worry about the battery, it looks after itself'
12. Kenya — EPRA / NITAQuestion 12

    How long should commissioning evidence normally be retained, at principle level?

    Until the invoice clearsTwelve monthsAt least the life of the longest equipment warranty on siteUntil the first service visit

Regional differences that matter

United States — NEC

IEEE 1547 and rapid shutdown. Interconnection behaviour follows IEEE 1547 profiles; rooftop DC conductor de-energisation follows NEC 690.12.