Electrical & Instrumentation QC Questions
1. Define ITP.
All inspections shall be done on the basis of approved ITP (Inspection Test Plan) which consists of the following sections;
- Activity Description
- Responsible Person
- Quality Inspection Activity
- Reference Drawings and Specifications
- Acceptance Criteria
- Verifying Documents (ITR’s)
- Intervention Points
2. Explain Intervention Points.
- W: Witness,
- S: Surveillance,
- A: Approval,
- M: Monitoring,
- R: Review,
- H: Hold
3. What is Method Statement?
This is construction document on which basis construction work shall be performed at site.
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4. What is NCR, CAR & PAR ?
- NCR: Non Conformance Report
- CAR: Corrective Action Report
- PAR: Preventive Action Report
5. What is MAR and MRIR?
- MAR: Material Approval Request
- MRIR: Material Receiving Inspection Report
Electrical Related Questions:
1. What you knows about International Standards like IEEE ,IEC, NEMA ,NFPA and API?
- IEEE stands for Institute of Electrical and Electronics Engineers.
- IEC stands for International Electrotechnical Commission.
- NEMA stands for National Electrical Manufacturers Association.
- NFPA stands for National Fire Protection Association.
- API stands for American Petroleum Institute.
2. IEC 60079-14 and IEC 60079-17 used for which purpose?
IEC 60079-14 is for Electrical Installations in Hazardous Areas and IEC 60079-17 is for Electrical Installations, Inspection and Maintenance.
3. Which type of inspections you have performed regarding Electrical work?
Power Control and Earthing Cables Installation, LV/MV Switchgear Installation, Transformer Installation, Power Distribution Boards Installation, UPS Panel and Battery Installation, Earthing System Installation, Lighting System Installation, Motors Solo Run & Installation check and CP System Installation etc.
4. What will you check during Lighting Final Installation and which drawing shall be used for this activity?
Lighting final installation shall be checked as per Typical Installation Detail Drawing and Lighting & Small Power layout drawing.
Also we have to check the existing inspection reports related to this activity like Cable Laying Inspection report, Cable IR/Continuity test report, Glanding & Termination inspection report.
5. By how many ways we can get the Cathodic Protection ?
Cathodic Protection (CP) may be achieved in either of two ways.
By the use of an impressed current from an electrical source, or by the use of sacrificial anodes.
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6. What are the main points, which we have to check during Motor Installation inspection?
The important points that we have to check during Motor Installation are as follows;
- Check Rated Voltage, Current, Speed, Frequency, IP Rating and Temp. class.
- Anti-condensation heaters installed continuity and IR test done. Check Phase to earth resistance (wherever applicable).
- Verify Current Transformer (CT) installation, connection etc are correct. (wherever applicable).
- Check stator winding connection and ensure that complies with nameplate/ data sheet.
- Check auxiliary terminal boxes (space heater, bearing/winding temperature/vibration etc).
Instrumentation Related Questions:
1. What you knows about explosion proof areas/zones ?
Zone 0, 1 & 2 for Gases and vapours. Zone 20, 21 & 22 for Dust protection.
2. What you know about Temperature classes for Electrical Instruments/Equipments, if T3 is mentioned over there on any instrument what that means?
It is surface temperature of a piece of electrical equipment.
With a temperature classification of T3, surface temp. of electrical equipment will not rise above 200 °C.
3. Which drawing shall be used for Final Instrument Installation inspection?
Typical Instrument Installation drawing.
4. If one Pressure Transmitter is installed at site, how many inspections are related to that one instrument?
- Cable Tray Installation Inspection.
- Cable Laying Inspection.
- Cable IR/Continuity Test Inspection.
- Cable Glanding & Termination Inspection.
- Instrument Tubing Installation Inspection.
- Final Instrument Installation Inspection
5. Which drawing shall be used for Instrument Tubing Installation inspection?
Hookup drawing shall be used for Tubing Installation of any Instrument.
6. During material inspection of a Level Transmitter (LT), what will you check and with reference to which documents?
- Material inspection shall be done as per approved ITP, data sheet and MR/MAR.
Also following necessary documents shall be checked;
- Instrument Calibration Report.
- Product Catalogue/Installation Manual.
- GA Drawings
- Vendor Data sheet.
- Inspection Reports (during manufacturing)
7. Did you worked on F&G (Fire and GAS) system, if yes please specify which type of F&G instruments you have worked on?
Gas detectors (Flammable Gas Detector, Toxic Gas Detectors, Hydrogen Gas Detector), Flame detectors, Heat detectors, Smoke detectors, Beacons/Horns, Manual call points.
8. At the stage of material inspection, which report we have to prepare?
MRIR: Material Receiving Inspection Report
9. What is the abbreviation of DCS, ESD and SCADA system ?
- DCS: Distributed Control System
- ESD: Emergency Shutdown System
- SCADA: Supervisory Control and Data Acquisition System
10. Why we use Analog and Digital I/O cards in DCS Control Module? Which inputs are Analog and which are Digital?
Analog I/O cards shall be used for Analog inputs like, RTD, Thermocouple etc. And Digital I/O cards are used for Digital inputs like Pressure switches etc.
11. What is IP rating?
IP stands for Ingress Protection, IP classifies and rates the degree of protection provided against intrusion (body parts such as hands and fingers), dust, accidental contact, and water by mechanical casings and electrical enclosures.
12. How we check the cable Insulation Resistance (IR) of multi triad cable.
We have to test the cable as following;
- Triad to Triad.
- Triad to Screen.
- Triad to Armour.
- Core to Core.
- Core to Screen.
- Core to Armour
13. What we have to check during loop checking of a control valve?
We have to note the following readings;
- Controller output.
- I/P Converter Output.
- Valve Positioner Output.
- Valve Position
14. What is ‘Accuracy’ in Instrument Calibration?
Accuracy is the term used to describe the degree of conformity of a measured or calculated value to its actual or specified value.
15. What is calibration span?
The calibration Span is defined as Upper Range Value (URV) minus Lower Range Value (LRV).
For Zero-based instruments, % Span is also known as % of Full Scale (% FS).
16. What is Instrument Error in calibration?
The difference between values indicated by an instrument and those that are actual.
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