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Key Facts: Iran Nezam Electrical Supervision Exam Exam

60 Questions

Total Questions

INBR / MRUD

150 minutes

Time Limit

INBR

50 / 100

Passing Threshold (clause 6-4, 1405 instruction)

INBR

3 wrong = 1 right

Negative Marking Rule

INBR

Open-Book

Exam Delivery Mode

INBR

Grade 3

Initial License Grade Awarded

IRCEO

The Iran Nezam Electrical Supervision examination is a 150-minute open-book paper of 60 four-option multiple-choice questions, held nationwide under the Office of National Building Regulations. It assesses an electrical engineer's supervisory duties, on-site testing and verification procedures (Topic 13), wiring and conduit workmanship, construction site electrical safety (Topic 12), and life-safety systems inspections (Topics 3 and 15). Negative marking applies and the pass threshold is 50 out of 100. The official paper is in Persian; OpenExamPrep provides independent English-language practice questions for the same topics.

Sample Iran Nezam Electrical Supervision Exam Practice Questions

Try these sample questions to review concepts for the Iran Nezam Electrical Supervision Exam exam. Each question includes a detailed explanation. Start the interactive quiz above for the full 100+ question experience with AI tutoring.

1During pre-commissioning testing of a newly wired residential sub-distribution board under INBR Topic 13, the electrical supervisor performs an insulation resistance test with a 500V DC Megger between live conductors and protective earth. What is the minimum acceptable insulation resistance value?
A.0.5 MΩ
B.1.0 MΩ
C.2.0 MΩ
D.5.0 MΩ
Explanation: According to INBR Topic 13 (Table of Verification Tests) and IEC 60364-6, for low-voltage installations with nominal circuit voltages between 50V and 500V (including standard 230/400V systems), the insulation resistance test voltage must be 500V DC, and the minimum acceptable insulation resistance is 1.0 MΩ. Values below 1.0 MΩ indicate degraded insulation or moisture ingress that must be rectified before energization.
2When verifying the insulation resistance of an Extra-Low Voltage circuit (SELV/PELV, nominal voltage ≤ 50V) in accordance with INBR Topic 13, what test voltage and minimum insulation resistance must the supervising engineer verify?
A.250V DC test voltage and 0.5 MΩ minimum resistance
B.500V DC test voltage and 1.0 MΩ minimum resistance
C.100V DC test voltage and 0.25 MΩ minimum resistance
D.1000V DC test voltage and 2.0 MΩ minimum resistance
Explanation: Under INBR Topic 13 and IEC 60364-6, circuits operating at SELV and PELV levels (up to 50V AC / 120V ripple-free DC) must be tested with a DC test voltage of 250V, and the measured insulation resistance between live parts and earth must be at least 0.5 MΩ. Using higher test voltages such as 500V DC could damage sensitive extra-low voltage components.
3Prior to conducting a mandatory insulation resistance test on a building distribution panel feeding electronic dimmers, LED drivers, and surge protective devices (SPDs), what preparatory action must the supervising engineer instruct the electrical contractor to take?
A.Energize the board to full load so heating drives out ambient moisture before applying test voltage
B.Disconnect all SPDs and sensitive electronic loads or short-circuit phase and neutral conductors together with respect to earth
C.Apply 1000V DC directly across phase and neutral to stress-test the electronic surge suppression capacitors
D.Test only with alternating current (AC) at 50 Hz to prevent electrostatic damage to solid-state controls
Explanation: INBR Topic 13 and IEC 60364-6 mandate that before insulation resistance testing, surge protective devices (SPDs) and sensitive electronic apparatus must be disconnected because SPDs will conduct at 500V DC (yielding a false dead-short reading) and high-voltage DC will destroy solid-state components. Where disconnection is impractical, phase and neutral conductors must be connected together and tested against protective earth.
4When measuring the resistance of a newly driven vertical earth rod electrode using the 3-point fall-of-potential tester (earth tester), how must the current probe (C2) and potential probe (P2) be positioned relative to the earth electrode (E)?
A.Place P2 at 25% and C2 at 50% of the total distance along opposite 180° directions
B.Place P2 at 62% of the distance between electrode E and current probe C2 along a straight line, with C2 at least 20 meters away
C.Place both P2 and C2 at exactly 5 meters from electrode E in triangular arrangement
D.Place P2 at 90% of the distance to C2 to capture the steepest resistance gradient
Explanation: Under INBR Topic 13 and IEEE 81, the 3-point fall-of-potential method requires driving current spike C2 at a sufficient distance outside the electrode's resistance zone (typically 20 to 30 meters minimum for a single rod) and placing potential spike P2 at approximately 61.8% (the 62% rule) of the total distance along the straight line E-P-C. This location corresponds to the true zero-potential plateau between the overlapping resistance areas.
5Before measuring the individual resistance of a building's earth pit electrode with an earth tester, which critical step must the supervising electrical engineer verify?
A.The main earthing disconnect link (test link) must be opened to isolate the electrode from the building earthing network
B.All incoming plumbing pipes must be bonded with temporary jumper cables to the test spikes
C.The main circuit breaker must remain closed and under full commercial electrical load
D.The test pit must be filled with 50 liters of brine solution 10 minutes prior to measurement
Explanation: INBR Topic 13 mandates that to measure the true resistance of an isolated earth electrode, the test link in the earth inspection pit or main earthing bar must be opened. If the link remains closed, the tester will measure the parallel combination of the building foundation earth, structural steel, metallic utility pipes, and the supply transformer neutral, yielding a false, unrealistically low resistance value.
6Under INBR Topic 13, what is the maximum acceptable overall resistance of the main earthing system for a typical residential building supplied by a public low-voltage TN-S or TN-C-S distribution network?
A.2.0 Ω
B.10.0 Ω
C.25.0 Ω
D.50.0 Ω
Explanation: INBR Topic 13 specifies that the overall resistance of the earthing system for a building connected to the public low-voltage network (TN-C-S or TN-S) must not exceed 2.0 Ω under normal conditions. Maintaining earth resistance at or below 2.0 Ω ensures that touch voltages remain below safe statutory limits (50V AC) during line-to-earth faults and guarantees rapid clearance by protective devices.
7A 230V final subcircuit feeding standard socket-outlets in a TN system is protected by a 16A Type B miniature circuit breaker (MCB). Under INBR Topic 13, what is the maximum allowable earth fault loop impedance (Zs) to guarantee automatic disconnection within 0.4 seconds?
A.1.44 Ω
B.2.88 Ω
C.4.50 Ω
D.0.72 Ω
Explanation: Under INBR Topic 13 and IEC 60364-4-41, automatic disconnection of supply requires Zs ≤ U0 / Ia. For a Type B MCB, the instantaneous magnetic trip current Ia is 5 × In = 5 × 16A = 80A. Given nominal phase voltage U0 = 230V, maximum permissible Zs = 230V / 80A = 2.875 Ω (approx 2.88 Ω). If measured Zs exceeds 2.88 Ω, the breaker will not trip instantaneously on a dead earth fault within 0.4 seconds.
8Under INBR Topic 13, what is the maximum permissible automatic disconnection time for 230V AC final branch circuits not exceeding 32A supplying portable equipment in a TN earthing system?
A.0.2 seconds
B.0.4 seconds
C.1.0 second
D.5.0 seconds
Explanation: INBR Topic 13 strictly adopts the international IEC 60364-4-41 standard for shock protection under Automatic Disconnection of Supply (ADS): for nominal line-to-earth voltage of 230V in a TN system, the maximum permissible disconnection time for final circuits with rated currents up to 32A is 0.4 seconds. Disconnection within 0.4 s prevents ventricular fibrillation during direct contact with exposed conductive parts during a fault.
9Under INBR Topic 13, which rated residual operating current (IΔn) is mandatory for Residual Current Devices (RCDs) installed for additional personal protection on domestic general-purpose socket-outlet circuits?
A.10 mA
B.30 mA
C.100 mA
D.300 mA
Explanation: INBR Topic 13 mandates that all general-purpose socket-outlets with rated current up to 32A must be protected by an RCD having a rated residual operating current (IΔn) not exceeding 30 mA. A 30 mA threshold provides proven physiological protection against fatal electric shock resulting from ventricular fibrillation in cases of direct or indirect contact.
10When carrying out instrumental testing of a general (non-time-delayed) 30 mA RCD under INBR Topic 13, what is the maximum statutory tripping time permitted when injecting a residual current of 1× IΔn (30 mA)?
A.40 ms
B.150 ms
C.300 ms
D.500 ms
Explanation: According to INBR Topic 13 and IEC 61008 / IEC 61557-6, when an AC or A-type general residual current device is tested at its rated residual operating current (1× IΔn, e.g. 30 mA), the device must trip within a maximum duration of 300 ms (0.30 seconds). A trip time exceeding 300 ms indicates mechanical sticking or sensing coil failure and requires immediate replacement.

About the Iran Nezam Electrical Supervision Exam Exam

The Iran Nezam Electrical Supervision exam is the official national professional licensure examination administered by the Ministry of Roads and Urban Development for electrical engineers seeking the supervision (Nezarat) practicing grade in the Construction Engineering Organization of Iran (IRCEO). Supervising electrical engineers are legally charged with verifying on-site electrical installations, conduit and wiring execution, earthing and bonding systems, switchboard fabrication and clearances, life-safety systems (fire alarm and elevators), temporary site electrical safety, and executing statutory pre-commissioning testing and verification in strict compliance with the Iranian National Building Regulations.

Exam sponsor: Office of National Building Regulations and Building Control (inbr.ir), Ministry of Roads and Urban Development; delivered nationwide by the National Organization for Educational Testing (Sazman-e Sanjesh) educational services company. The requirements and fees below concern the certification or admission exam, separate from our free practice resources.

Assessment

60 four-option multiple-choice questions covering electrical testing and commissioning (Topic 13), wiring and equipment inspection (Topic 13, Publication 110), supervisory duties (Topic 2), site electrical safety (Topic 12), and fire alarm/elevator inspections (Topics 3, 15)

Time Limit

150 minutes

Passing Score

50 out of 100 (50%) — clause 6-4 of the official 1405 registration instruction, calculated after the negative-marking deduction

Exam / Certification Fees

Set per sitting and shown in the inbr.ir registration cart; the official 1405 registration instruction does not publish a fixed amount

Exam sponsor website

Fees, eligibility, and exam policies can change. Confirm them with the exam sponsor before applying or paying.

Our practice resources: topics covered

We aim to reflect publicly available exam outlines and topic information in our study resources. Coverage, format, and difficulty may differ from the actual exam, and we cannot guarantee that every detail is accurate or current. Confirm exam requirements, fees, and policies with the official exam sponsor.

25%

Electrical Testing & Commissioning (INBR Topic 13)

Mandatory testing procedures: insulation resistance measurement with 500V DC Megger, earth electrode resistance measurement by 3-point fall-of-potential method, earth fault loop impedance, RCD operating current and trip time under 300 ms, phase sequence, polarity verification, and continuity testing of protective bonding conductors

25%

Wiring & Conduit Installation Supervision (INBR Topic 13 & Pub 110)

Supervising physical installations: PVC/metal conduit bending radii and fill factor (max 40%), minimum embedding depths in walls and slabs (1.5 cm cover), junction box placement and accessibility, conductor color identification, termination torque, cable tray grounding, switchboard clearances (min 0.8-1.0 m), and ingress protection (IP ratings)

20%

Supervisory Procedures & Legal Duties (INBR Topic 2 & Law)

Issuance of mandatory stage reports (rough-in, pre-pour, testing, energization), contractor non-conformance notices, municipal stop-work orders, inter-disciplinary coordination with civil and mechanical supervisors, and engineer professional liability under Article 34

15%

Jobsite Electrical Safety (INBR Topic 12)

Temporary power supervision on construction sites: site distribution boards, mandatory 30 mA RCD protection on temporary sockets, overhead power line safe approach distances, crane and scaffolding protective bonding, and temporary electrical cord safety

15%

Fire Alarm & Elevator Electrical Inspection (INBR Topics 3 & 15)

Supervision of life-safety electrical installations: fire alarm detector spacing, manual call point mounting heights (1.10-1.40 m), fire-resistant cabling and smoke damper interfaces; elevator machine room main switch, phase failure/reversal relay, car top inspection station, and pit emergency stop switch

Preparing for the Iran Nezam Electrical Supervision Exam Exam

What You Need to Know

  • Passing score: 50 out of 100 (50%) — clause 6-4 of the official 1405 registration instruction, calculated after the negative-marking deduction
  • Assessment: 60 four-option multiple-choice questions covering electrical testing and commissioning (Topic 13), wiring and equipment inspection (Topic 13, Publication 110), supervisory duties (Topic 2), site electrical safety (Topic 12), and fire alarm/elevator inspections (Topics 3, 15)
  • Time limit: 150 minutes
  • Exam / certification fees: Set per sitting and shown in the inbr.ir registration cart; the official 1405 registration instruction does not publish a fixed amount Official sources

Using Our Practice Resources

  • Work through all 100 available questions
  • Review every answer and explanation
  • Track weak areas and revisit them
  • Use our AI tutor for tough concepts

Iran Nezam Electrical Supervision Exam: Suggested Study Strategy

1Master the testing and verification tables in Topic 13, including minimum insulation resistance values, maximum disconnection times, and earth electrode testing methods
2Memorize statutory installation dimensions: conduit embedding depth (min 1.5 cm cover), switchboard clearance (min 0.8-1.0 m), and manual call point heights (1.10-1.40 m)
3Understand the legal stage reporting workflow under Topic 2, knowing when the electrical supervisor must submit pre-pour, rough-in, and final commissioning reports
4Learn the exact conductor color codes (L1: brown, L2: black, L3: gray, Neutral: light blue, PE: green-yellow) and conduit fill limits (max 40% for 3+ cables)
5Practice disciplined open-book exam technique with index tabs and practice negative-marking strategy to avoid speculative guesses that erode your net score

Frequently Asked Questions

What is the format of the Iran Nezam Electrical Supervision exam?

The examination consists of 60 four-option multiple-choice questions to be completed in 150 minutes. Clause 6-2 of the official 1405 registration instruction confirms the paper is held open book, so candidates may bring approved INBR books (Mabahes) and notes. Negative marking applies: three incorrect answers cancel one correct answer. The official paper is set in Persian.

What passing score is required for the Electrical Supervision exam?

Clause 6-4 of the official 1405 registration instruction sets the passing threshold at 50 out of 100 (50%). Because three incorrect answers cancel one correct answer (deducting 1/3 point per mistake), candidates who answer questions incorrectly must achieve more than 30 raw correct answers to reach the 50% net threshold. A passing score remains valid for up to 3 years toward obtaining the Grade 3 (Payeh 3) supervision license.

What are the eligibility requirements for the Electrical Supervision license exam?

Candidates must hold an accredited Bachelor's, Master's, or Ph.D. degree in Electrical Engineering (Power, Control, Electronics, or Telecommunications recognized by the Ministry of Science). A minimum period of post-graduation practical work is required: 3 years for Bachelor's holders, 2 years for Master's holders, and 1 year for doctoral holders, alongside active provincial Nezam membership.

Which National Building Regulations (INBR) and references are tested in Electrical Supervision?

The core tested texts include INBR Topic 13 (Design and Execution of Electrical Installations - specifically testing, verification, earthing, and workmanship), Topic 1 (Definitions), Topic 2 (Administrative Regulations and Supervisory Duties), Topic 3 (Fire Protection - fire alarm and emergency lighting), Topic 12 (Construction Site Safety - temporary electrical works), Topic 15 (Elevators and Escalators - electrical controls and safety switches), and Management and Planning Organization Publication 110 (Technical Specifications for Electrical Installations).

What are the key on-site testing requirements a supervising electrical engineer must verify under Topic 13?

Under Topic 13, the supervising engineer must verify: (1) insulation resistance with a Megger (minimum 1.0 MΩ at 500V DC for 230/400V installations); (2) earth electrode resistance using the 3-point fall-of-potential tester; (3) earth fault loop impedance to confirm automatic disconnection times; (4) residual current device (RCD) tripping current (30 mA) and tripping time (<300 ms at 1x IΔn); (5) polarity of switches and single-pole protection devices; (6) phase sequence (clockwise rotation); and (7) continuity of protective conductors (PE) and equipotential bonding (<0.05 Ω).