Interview Question for QA/QC Electrical and Instrumentation Inspector
General Questions
QWhat is Q.C./Quality Control?
Ans1)-Quality control is an inspection or testing of products to uncover defects and reporting to management who make decision to allow or deny the product release.
2)-Quality control is an operational technique (inspection, testing, and examination) that are used to fulfill the quality requirements.
QWhat is Q.A./Quality Assurance?
Ans1)-Quality assurance attempts to improve and stabilize the production by avoiding or minimizing the issues which led to defects.
2)-Quality assurance is the system of action and planning needed to provide a service or product will satisfy the requirements of quality.
QWhat are the responsibilities of QA/QC inspector at site?
AnsA QA/QC inspector is responsible for quality control and quality assurance of all the construction works, and all the work at site should be according to standards, approved procedures and ITP’s. When some construction activity starts, QC will do internal inspection and will do review of documents before raising the RFI. If there is some violation or non-conformance in work then QC shall raise NCR. When there is some issue/complication/irregularity regarding to construction activity then QC will consult with his QC supervisor and construction representative to resolve it.
QWhat is schedule Q? How many attachments it has?
AnsSchedule Q is an Aramco document that describes the project quality requirements, inspection schedules and procedures, documentation requirements, contractor and subcontractor quality personnel qualification requirements and quality requirements for contractor supplied materials.
It has 6 attachments:
(1)Attachment-I >> Contractor and Subcontractor Quality Personnel Qualification Requirements
(2)Attachment-II >> Saudi Aramco Standards and Procedures Containing Quality Requirements
(3)Attachment-III >> Quality Requirements for Contractor Supplied Materials
(4)Attachment-IV >> Quality Requirements for the Construction Phase
(5)Attachment-V >> Summary of Quality System Deliverables
(6)Attachment-VI >> Project Specific Quality Requirements
QWhat is the quality plan?
Ans1)-It includes procedures and documents, covering work activities and description of sequences of work.
2)-Quality Plan include inspection, testing and proper documentation.
3)-Document specifying which procedures and associated resources will be applied by whom and when to a specific project, product or process.
QWhat is SAES, SAEP, SAIP, SAMSS, SAER, GI, SATIP, ITP, SAIC, QMIS, RFI?
AnsSAES: Saudi Aramco engineering Standards SAEP: Saudi Aramco engineering procedures SAIP: Saudi Aramco inspection procedure
SAMSS: Saudi Aramco materials systems specifications
SAER: Saudi Aramco engineering report
GI: Saudi Aramco general instructions
SATIP: Saudi Aramco typical inspection plan
SATIP is a document which provides us information related to activity, activity number, SAIC number and responsibility of contractor and client QC personnel inspection level.
ITP: Inspection and test plan
SAIC: Saudi Aramco inspection checklist
QMIS: Quality management information system
RFI: Request for inspection
QName some international standards which you follow for electrical and instrument work?
AnsIEEE: Institute of electrical and electronic engineers
NEC: National electrical code
IEC: International electrotechnical commission
NEMA: National electrical manufacturers association
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NFPA: National fire protection association
NACE: National association of corrosion engineers ANSI: American national standards institute ASTM: American society for testing and materials UL: Underwriters laboratories
AEIC: Association of Edison illuminating companies
ICEA: Insulated cables engineering association
IS: International standards
ISO: International standards organization
BS: British standards institution
QHow will a QC inspector raise a RFI?
AnsWhen some activity starts, QC will do internal inspection and will do review of documents and then will raise the RFI.
QHow much time before the inspection you will raise RFI?
Ans24 hours before the inspection time.
QWhat is the inspection, documentation, document review, standards, hold point, witness point?
AnsInspection: An activity such as measuring, examining, testing one or more characteristics of a product/equipment and comparing the results with specified requirements (standards and procedures) in order to know whether conformity is achieved or not for each characteristic.
Documentation: Any record or pictorial information describing, defining the procedures or results.
Document review: To collect all the documents related to an activity and to evaluate the requirements for quality of that specific activity are fulfilled or not and to identify if there is any problem or non-conformity exists.
Inspection assignment package: A set of documents that include details of purchased material/equipment, needed to perform full inspection at the vendor/sub-vendor facility.
Standards: A document approved by a generally recognized body.
Specification: A detailed description of the design and materials used to make something.
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Quality management system: All activities that determine the quality policy, objectives and responsibilities, and implement them by means such as quality planning, quality control, quality assurance.
Quality System: Organizational structure, procedures, processes and resources needed to implement the quality arrangements and requirements.
Quality audit: A systematic and independent examination to determine whether quality activities and related results comply with the planned arrangements and whether these arrangements are implemented effectively and are suitable to achieve objectives.
Hold point: Inspection or test stage beyond which work/activity should not proceed without the QA/QC organization representative in attendance.
Witness point: A point that provides QA/QC representative with the opportunity to attend the inspection/test at his option.
Surveillance: Generally visiting the site work without RFI.
Compliance: A judgment that the product or service meets the requirements of the relevant specification or standard.
Non-conformity: Non-fulfillment of a specific requirement of the relevant specification or standard.
Corrective action: Action taken
to eliminate the defect or existing non-conformity, or other undesirable situation.
Preventive action: Action taken to eliminate the causes of the existing non-conformity, defect or other undesirable situation in order to prevent recurrence.
Procedure: A specified way to perform an activity.
Pre-commissioning: Testing of system components for continuity, operability.
Commissioning: Process by which an equipment, facility, or plant (which is completed or near completion) is tested to verify if it functions according to its design objectives or specifications.
QWhat is NCR, Define and explain it with example?
AnsNone-conformance report, we raise NCR when there occur some non-conformity/violation at the site during the construction work or when there is some non-conformity/violation occurred during material receiving.
There are 4 parts of a NCR... (1) Violation occurred (2) Root cause analysis (3) Corrective action to be taken (4) Preventive action (Recommendations to avoid re-occurrence of violation).
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QWhat will you do when you see some violation/non-compliance has occurred at site?
AnsI will put internal NCR at once and then after that I will ask to construction team to take action to rectify it.
QAfter how much time of occurrence of violation you will raise NCR?
AnsWithin 24 hours
QWithin how much time the violation/non-conformity should be resolved?
AnsAs per ACD-(Agreed Completion Date).
QThere are how many types of NCR?
Ans:There are 2-types of NCR, and what is the difference between them?
1-Internal NCR
2-LBE Standard Violation/Client NCR 3- Company NCR
Internal NCR is a NCR which is raised by the Contractor QC-Inspector and LBE/Client NCR is a NCR which is raised by PID (Client QC-Inspector)
QHow many types of RFI are?
AnsThere are two type of RFI; (1) Internal RFI (2) QMIS RFI
QWhat is walk through?
AnsPreparation of balanced work report (punch list items) upon completion of 80% of construction work
QWhat is punch list items?
AnsAny balanced work report during completion of work is called punch list items.
QWhat is two week look ahead schedule?
AnsIt is the schedule of work that have to do/complete in the next two weeks. The project planner/ project scheduler will prepare two week ahead schedule.
QWhat is the T.Q?
AnsIf there is some conflict/issue occurred to execute work as per approved IFC Drawing, T.Q is raised according to site requirement and the designer/CSD/Client will approve it.
QWhat is red-mark/as-built drawing?
AnsChanged drawing according to the site requirement, for example re-routing/re-location of cable/conduit/equipment.
QTo deviate from any standard and other Mandatory Saudi Aramco Engineering Requirements (MSAERs), what is the procedure?
AnsAs per SAEP-302, if there any conflict between Mandatory Saudi Aramco Engineering Requirements (MSAERs) or referenced industry standards shall request the Manager, Consulting Services Department (CSD) of Saudi Aramco, Dhahran to resolve the conflict.
To deviate from any standard, requests shall be submitted electronically through the SAP Waiver Process in accordance with SAEP-302.
QFor obtaining a Waiver of a Mandatory Saudi Aramco Engineering Requirement which standard we follow?
AnsFor obtaining a waiver of a Mandatory Saudi Aramco Engineering Requirement we follow SAEP-302.
Power Supply
*Where instrument-circuit power distribution panels are used, each panel shall be dedicated to a single voltage level. These panels shall not provide power to non- instrumentation circuits. Distribution panels shall be furnished with a minimum of 20% spare circuit breakers.
*Redundant power supplies feeding process automation systems, emergency shutdown systems, metering systems, auxiliary systems or field instrumentation shall be fed from separate distribution panels.
*Power wiring for field instruments, two-wire analog transmission loops, field switch contacts, etc., shall be individually fused and provided with a means of disconnecting the power without disturbing terminated wiring. Visual indication of a blown fuse condition shall be provided.
*Low level signals are defined as Millivolt, Microamp, Pulse and Frequency Signals under 1 Volt.
*Where multiple online DC power supplies are connected to a single power bus, diode auctioneering shall be used to ensure bump less transfer in the event of a single power supply failure.
*Where multiple DC power supplies are an integral part of a manufacturer's standard product, the manufacturer's standard method of load sharing shall apply.
*UPS power and utility power shall not share the same cable or be routed in the same conduit.
*UPS systems powering critical instrumentation shall consist of redundant UPS units.
*Critical instrument systems are defined as systems which, upon loss of their supply power, would cause: 1) process failure in a non-failsafe mode, 2) area or plant shutdowns, 3) loss of custody transfer metering or accounting systems, or 4) other adverse facility operating scenarios.
*The time during which the battery bank shall supply power to the instrumentation system shall depend on the application, but not be less than 30 minutes.
*Backup power supply shall be required for instrumentation systems containing volatile memory. For all such systems, the manufacturers' recommendations shall be followed.
QWhat is the function of diode auctioneering? And where is it used?
AnsDiode auctioneering shall be used to ensure bump less transfer in the event of a single power supply failure.
Signal/Control Wiring
*Splices are not permitted in wiring. When wiring must be extended, connections shall be made via terminal blocks in a junction box installed above ground.
*Twist-on wire nut connectors shall not be used for making any electrical instrumentation terminations or wiring connections.
QWhat are the wire and cable minimum size requirements for field instrument to field junction box in instrument circuits?
AnsThe minimum wire size for single pair cable from field instrument to field junction box shall be 16 AWG/300V, 600V.
QWhat are the wire and cable minimum size requirements for field junction box to marshalling cabinet in instrument circuits?
AnsThe minimum size for multi-pair/triad cable from field junction box to marshalling cabinet shall be 18 AWG/300V, 600V.
*The minimum size for multi-pair/triad cable should be 18 AWG. The minimum wire size for single pair cable shall be 16 AWG.
*Type ITC cable shall not be installed on either non-power limited circuits or powered limited circuits operating at more than 150 volts or more than 5 amperes.
*Differences in the manufacturer recommended cable and these requirements shall be resolved with Instrumentation Unit/PID/P&CSD.
QHow protection is provided against reverse EMF for inductive loads?
AnsProtection against reverse EMF shall be provided for inductive loads such as relays, solenoids, etc. This may be accomplished by installing a diode across the coil for DC loads or a metal oxide varistor (MOV) across the coil for AC inductive loads.
*If a discrete loop length exceeds 1000 feet, 120 VAC signal shall not be used due to potential capacitive or inductive coupling. In such cases, DC voltage shall be used.
*Cables used in Class 1, Class 2 and Class 3 circuits shall meet the requirements of Article 725 of the National Electrical Code (NEC).
Routing
QHow the instrument cable is laid above ground from the field instrument to the field junction box?
AnsSingle twisted pair/triad cables shall be installed in RGS or PVC Coated RGS conduits from the field instruments to the field junction boxes and armored instrumentation cable shall be routed on a cable tray.
QHow an armored cable is laid above ground from the field junction box to marshaling cabinets?
AnsCables between field junction boxes and marshaling cabinets may be routed in conduits, on trays, or direct buried.
QWhat is the marshaling cabinet?
AnsA marshalling cabinet contains main terminal strips and wire terminations.
QWhat is the minimum separation between power and instrumentation cables?
AnsPower cables and instrumentation cables have minimum separation between given blow:
1)Conduit to Conduit Spacing, millimeters (inches)
NSL *Level 1Level 2Level 3
Level 10 (0)75 (3)300 (12)
Level 275 (3)0 (0)150 (6)
Level 3300 (12)150 (6)0 (0)
2)Tray to Conduit Spacing, millimeters (inches)
NSL *Level 1Level 2Level 3
Level 10 (0)100 (4)450 (18)
Level 2100 (4)0 (0)150 (6)
Level 3450 (18)150 (6)0 (0)
3)Tray to Tray Spacing, millimeters (inches)
NSL *Level 1Level 2Level 3
Level 10 (0)150 (6)650 (26)
Level 2150 (6)0 (0)200 (8)
Level 3650 (26)200 (8)0 (0)
*Twisting and shielding of instrumentation wiring shall also be used as detailed below to minimize the noise impact on instrumentation signals.
Termination
QWhat type of terminal blocks are used for termination of instrument cables?
AnsTerminal blocks shall be screw type and channel (rail) mounted, strip type, with tubular box clamp connector and compression bar or yoke for wire termination. As a minimum, the thickness of the terminals shall be 5 mm or higher. Multi-deck and spring type terminal blocks are not acceptable.
QWhat is instrument termination?
AnsWhen installing instrumentation, cable is run from the marshaling cabinet, or some control system to the instrument in the field. The act of attaching the cables to the actual electrical terminals of the instrument or input output terminal at the Transmitting or receiving end is called Terminating the instrument, i.e. instrument termination. Usually the instrument loop is installed in stages, where the instrument is physically mounted in the field, cable is pulled and run in cable trays or buried in trenches, and the ends of the cables are terminated.
QWhat type of terminal blocks are used for termination of instrumentation cables?
AnsScrew-type terminals are provided on field instruments or other electrical devices, solder less crimp/compression connectors shall be used for connecting stranded copper conductors.
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*The thickness of the terminals shall be 5 mm or higher.
*Multi-deck and spring type terminal blocks are not acceptable. Connections at Field Instruments:
(1)All connections at the field instrument shall be made on screw type terminal blocks. Wire nuts and spring type terminals shall not be used. Instruments with integral terminal blocks shall be connected directly to the field cable.
(2)If the instrument is fitted with factory sealed fly leads then they shall be connected to a screw type terminal block installed in a GUA conduit fitting.
The outer jacket of shielded twisted single pair/triad cables shall be left intact up to the point of termination. Drain wires and mylar shields on shielded cables shall be cut and insulated with heat shrink sleeve at the field instrument unless otherwise specified by the instrument manufacturer.
Connections at Field Junction Boxes
Conduit and cable entries to field junction boxes shall be through the bottom. Top entry is allowable provided a drain seal is installed on the conduit within 18" of the enclosure. Side entry (within six inches of the bottom) shall be permitted only when space limitations dictate. The number of conduit entries shall be kept to a minimum. All unused entry ports shall be fitted with approved plugs.
In severe corrosive environments, cable glands shall be protected against corrosion, either by a heat shrink sleeve, anti-corrosion tape or PVC shroud with anti-corrosion compound. Gasket materials shall be oil resistant.
QWhat are the terminals/terminal blocks accessories?
AnsTerminals and terminal block accessories are end brackets, DIN rail mounting brackets for electrical insulation, bus-bar support blocks, etc.
QWhat should be material specifications of terminal blocks accessories?
AnsShall be made of fire retardant, halogen free, high strength material such as polyamide or equivalent in accordance with UL 94, V0. Brittle materials such as melamine shall not be used.
*Wires terminated on these terminal blocks shall not have the bare ends coated with or dipped in solder (“tinned”). However, termination of wiring that has individual strands of the copper conductor tinned during manufacture is acceptable.
*No more than two bare wire ends shall be connected to each side of a single terminal block.
QWhat type of wire ducts & gutters are used and what is the purpose?
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AnsPlastic wire ducts with removable covers shall be used in control panels and marshaling cabinets.
The purpose is to provide a means of routing and organizing wiring between terminal blocks and instrument racks or panels for cable termination.
QHow much distance should be between the wire duct and the terminal strips?
AnsA minimum of 50 mm (two inches) shall be maintained between the duct and terminal strips to permit wire markers to be completely presented without being obscured by the duct.
Identification
QWhat is the wire tagging method? How we do wire tagging?
AnsAll wiring shall be tagged at each end. Each wire tag shall have two labels. The first label (closest to the end of the wire) shall identify the terminal number to which the wire is physically connected. The other label shall be the terminal number of the connection of the opposite end of the wire.
The terminals in each row shall be sequentially numbered starting at number one (1).
Grounding
QWhat is the hazard location in area classification?
AnsHazardous locations are: CLASS I, ZONE 0 & CLASS I, ZONE 1
Connections and Terminations
*Compression (crimped) type connectors shall be used for splicing and terminating stranded conductors.
*The use of solder lugs is prohibited.
*Compression terminal connectors for 4/0 and larger conductors shall be two hole NEMA design.
*All compression connectors shall be tinned copper.
QWhat type of connectors are used for lighting and receptacle circuits?
AnsSpring pressure type twist-on connectors, and pressure set screw connectors with insulating caps are permitted for lighting and receptacle circuits in non-hazardous locations, and in non- industrial applications.
QWhat type of connectors are used for control wiring?
AnsInsulated ring tongue, locking fork tongue, flanged fork tongue and pin type compression terminals shall be used for control wiring.
*All threaded cable fittings including terminators (glands) for metric size cables shall have tapered (NPT) threads in accordance with ANSI/ASME B1.20.1.
QWhat is the cable identification method for electrical cables?
AnsIdentification of cables shall include the cable number and destination.
Individual control wires shall be identified by two labels at each end. The first label (closest to the end of the wire) shall identify the number of the terminal to which the wire is connected. The other label shall identify the terminal of the opposite end of the wire.
QWhat are marking methods for wires for terminations?
AnsWires at termination points shall be identified by the use of:
(a)Permanently imprinted or embossed wire markers of the heat-shrinkable or slip-on type. Slip-on wire markers shall be sufficiently tight so that they will not slip unintentionally.
(b)Cables may be identified by special plastic or non-corrosive metal labels held with cable ties, or similar methods.
(c)Colored insulating tapes may be used for phase identification of power circuit conductors.
* Wrap-around, rigid Snap-on, or adhesive type markers are not permitted for wire or cable identification.
QHow to identify the individual phases of power cable circuit?
AnsSAES-P-104 describe that, individual phases of power circuit shall be identified by the color-coding cable (Red, Yellow, Blue).
QWhat is creepage distance? How much creepage distance for 13.8 KV outdoor terminations?
AnsThe clearance between the terminated ends of phase to the ground is called creepage distance.
For 13.8 kV outdoor terminations, each phase shall have a creepage distance of 552 mm to ground minimum.
QWhat is the creepage distance for medium and high voltage terminations installed outdoor?
AnsMedium and high voltage terminations (operating at 2.4 kV and above) installed outdoors shall have a minimum creepage distance to ground of 40 mm per kV line-to-line nominal system voltage.
QWhat is the creepage distance for medium and high voltage terminations installed indoor?
AnsMedium and high voltage terminations installed indoors shall have a minimum creepage distance to ground of 25 mm per kV line-to-line nominal system voltage.
QWhat is the minimum creepage distance for MV/HV terminations?
AnsFor outdoors installed is 40 mm per KVL-L and indoors installed is 25 mm per KVL-L.
QAccording to SAES-P-104, Cable glands should be in accordance with?
AnsCable glands (for hazardous and non-hazardous locations) shall be in accordance with BS 6121 or BS 50262.
Enclosures
QAccording to SAES-P-104, which type of terminal/ equipment enclosure shall be used in outdoor plant areas?
AnsIn outdoor plant areas, terminal/equipment enclosures shall be:
(a)NEMA Type 4
(b)NEMA Type 3
(c)IEC 60529, Type IP54 or better.
QAccording to SAES-P-104, which type of terminal/equipment enclosure shall be used in outdoor plant areas in severe corrosive environment?
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AnsIn outdoor plant and other industrial areas located in severe corrosive environments, equipment and terminal enclosures shall be:
(a)NEMA Type 4X
(b)NEMA Type 4 or 3
(c)IEC 60529, Type IP 54 or better
QAccording to SAES-P-104, what type of enclosure material shall be?
AnsEnclosure materials shall be
a)Aluminum (Copper Free -0.4%)
b)Plastic (Fiberglass)
c)Stainless steel (Type 304 or better)
d)Galvanized/Painted/Coated carbon steel in indoor air conditioned area.
QAccording to SAES-P-104, which equipment/terminal enclosure shall be used in outdoor non- industrial area?
AnsIn outdoor non-industrial areas, equipment and terminal enclosures shall be:
(a)NEMA Type 3R, 3 or 4
(b)IEC 60529 Type IP34 or better
QAccording to SAES-P-104, which type of enclosure shall be used for dry-type transformers in outdoor locations?
AnsIn outdoor locations, enclosures for small dry-type transformers shall be totally enclosed NEMA Type 3R.
*In hazardous (classified) locations, enclosures that are required to be approved for Class I locations by NEC Article 501 or 505.
QWhat type of breathers and drain fitting shall have in enclosures and junction boxes?
AnsEnclosures and junction boxes having an internal volume exceeding 2,000 cm³ shall be provided with Type 300 Series stainless steel breather and drain fittings.
QAS per SAES-P-104, what is the size of drain hole?
AnsSAES-P-104, says thin wall enclosure and junction box may be drill by 5mm hole in the bottom.
Conduit, Conduit Fittings and Supports
QWhat are the specifications of direct buried PVC conduit, as per SAES-P104?
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AnsDirect buried conduit shall be PVC conduit Type DB-120 per NEMA TC 6 & 8 or Type EPC-40-PVC per NEMA TC 2.
QWhat are the specifications of concrete encased underground conduit as per SAES-P104?
AnsConcrete encased conduit shall be PVC conduit Type EB-35 or DB-120 per NEMA TC 6 & 8 or Type EPC-40-PVC per NEMA TC 2.
QWhat are the specifications of direct buried conduit for corrosive area, as per SAES-P104?
AnsDirect buried conduit in class I division I (Classified area) shall be PVC coated RGS conduit.
QWhat are the specifications of aboveground/exposed conduit, as per SAES-P104?
AnsConduit installed exposed, above ground in outdoor, industrial facilities shall be rigid steel per ANSI C80.1, and in addition it shall be galvanized.
QWhat are the specifications of aboveground conduit in severe corrosive environments as per SAES-P104?
AnsConduit above ground in severe corrosive environments shall be rigid steel per ANSI C80.1, and it shall be galvanized, in addition, it shall be factory PVC coated (1 mm) per NEMA RN 1.
*Where flexibility is required, liquid-tight flexible metal conduit (non-hazardous and Class I, Division 2 and Zone 2 locations) or explosion-proof neoprene coated or PVC coated flexible couplings (in Class I, Division 1 and Zone 1 locations) shall be used.
*EMT (electrical metallic tubing) is acceptable only for indoor non-hazardous location. EMT shall comply with the requirements of ANSI C80.3.
*Intermediate metal conduit (IMC) is prohibited.
QWhat is the minimum size of conduit shall be, as per SAES-P-104?
AnsThe minimum conduit size shall be ¾ inch or equivalent.
*In non-industrial areas and for instrumentation wiring the minimum size conduit shall be ½ inch.
*Conduit and threaded conduit fittings shall have tapered (NPT) threads in accordance with ANSI/ASME B1.20.1.
*Field cut conduit threads shall be coated with a zinc rich protective coating.
QWhat type of conduit fittings are used for outdoor rigid steel conduit and liquid-tight flexible metal conduit as per SAES-P-104?
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AnsConduit fittings for outdoor rigid steel conduit and liquid-tight flexible metal conduit shall be of steel, iron, either hot-dip galvanized, or zinc electroplated.
QWhat type of conduit fittings are used for aboveground rigid steel conduit and liquid-tight flexible metal conduit, as per SAES-P-104?
AnsConduit fittings for rigid steel conduit and liquid-tight flexible metal conduit used above ground in severe corrosive environments shall be steel, iron, either hot-dip galvanized, or zinc electroplated and in addition, shall be factory-coating with PVC or field coating prior to installation.
*Conduit fittings for direct buried PVC coated rigid steel conduit shall be factory PVC coated.
*Threads of plugs, junction boxes and other fittings shall be lightly lubricated with a rust preventive grease before assembly.
*The use of conduit unions with underground conduit should be avoided. If this is not possible, conduit unions must be protected with heat-shrinkable sleeves or wrap-arounds.
QAs per SAES-P-104, pvc conduit fittings shall be in accordance with which standard?
AnsFittings for NEMA TC 6 & 8 Type PVC conduit shall be in accordance with NEMA TC 9.
Fittings for NEMA TC 2 Type PVC conduit shall be in accordance with NEMA TC 3.
QWhat type of supports are used to support conduits, cable trays, enclosures, lighting fixtures and other electrical equipment?
AnsChannel erector system components used to support conduits, cable trays, enclosures, lighting fixtures and other electrical equipment shall be made of steel or iron, either hot-dip galvanized (preferably), or zinc electroplated.
QWhat type of supports are used to support conduits, cable trays, enclosures, lighting fixtures and other electrical equipment in severe corrosive environment?
AnsShall be made of
(A)Steel or iron, either hot-dip galvanized (preferably), or zinc electro plated and in addition, shall be factory-coating with PVC or field coating prior to installation. (B) Stainless steel (C) Fiberglass
Cable Trays
QWhat kind of material is used for the cable trays?
AnsAccording to SAES-P-104, cable trays materials shall be
a)Aluminum (copper free 0.4%).
b)Fiber glass.
c)Stainless steel
d)Galvanize carbon steel in indoor air-conditioned area.
QAccording to SAES-P-104, Aluminum and galvanized carbon steel cable trays are designed, manufactured, rated and tested in accordance with?
AnsAluminum and galvanized carbon steel cable tray shall be designed, manufactured, rated, and tested in accordance with NEMA VE 1.
QAccording to SAES-P-104, Fiberglass cable trays are designed, manufactured, rated and tested in accordance with?
AnsFiberglass cable tray shall be designed, manufactured, rated, and tested in accordance with NEMA FG 1.
QWhat is purpose of providing the cover of cable tray?
AnsCover provide for protection from sun light and mechanical damage.
QHow much spacing require on expansion joint for aluminum cable tray?
AnsSpacing between expansions joint that allowed a 25 mm movement in 20 meters
Underground Cable Systems
QWhat are the minimum depth of burial requirements for underground installations? AnsMinimum depth of burial requirements for underground installations are as follows:
Millimeters from Grade Level to the Top Surface of Cable, Conduit or Duct Bank
System Voltage
Direct Buried Cables
Direct Buried PVC
Duct Bank and Direct Buried Rigid Steel
600 V and below
610
460
460
Over 600 V to 35 kV
920
610
460
Over 35 kV
1070
760
460
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QWhat is the underground conduit installation depth requirements in rocky areas, in areas where cables being below the water table, or to avoid underground obstructions such as other cables, conduits or piping?
AnsIn rocky areas where digging must be minimized, in areas where cables being below the water table, or to avoid underground obstructions such as other cables, conduits or piping, cables may be installed in one of the following configurations with total cover of 300mm or 150 mm:
(a)PVC coated rigid steel conduit with a total cover not less than 300 mm, which shall include a 50 mm thick (minimum) reinforced concrete slab over the conduit; or
(b)PVC coated rigid steel conduit with a total cover not less than 150 mm, which shall include a 100 mm thick (minimum) reinforced concrete slab over the conduit; or
(c)A reinforced concrete encased duct bank with 150 mm of total cover, measured from the top of the upper conduit, which shall include a minimum of 100 mm of concrete over the upper conduit.
*The top layer of the concrete slab or the duct bank shall be mixed with red dye. (Minimum thickness of red concrete layer should be 5 mm).
QWhat is the mini thickness of red concrete tiles?
AnsSAES-P-104, minimum thickness of red concrete tiles is 50mm/5cm and are placed 300mm above direct buried cable or direct conduit, in addition, a yellow warning tape shall be installed over the tiles. Tiles dimensions are 200x400 mm.
QWhat is the depth, width of trench? And what is the minimum sand bedding height? And what is the minimum height of sweet sand before the yellow warning tape?
AnsFor direct buried cable trench the minimum depth is 610 mm from the top surface of the cable and minimum sand bedding is 150 mm and minimum height of sweet sand over the cable is 300 mm and then put red tiles and yellow warning tape and then backfill it.
QWhat type of duct banks are used for underground cable systems?
AnsDuct banks shall consist of PVC conduit, encased in concrete.
(1)The minimum burial depth from the grade level to the top surface of duct bank is 460 mm.
(2)There shall be a minimum of 75 mm of concrete from the outside surface of the duct bank to any conduit or reinforcing steel.
(3)In duct banks with steel conduit, unreinforced non-structural concrete shall be used.
(4)In duct banks with PVC conduit, under areas with no traffic, or occasional traffic, unreinforced non-structural concrete shall be used.
(5)In duct banks with PVC conduit, under areas with frequent traffic, such as roads and parking lots inside plants or communities, reinforced concrete shall be used.
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*There shall be a minimum of 75 mm of concrete from the outside surface of the duct bank to any conduit or reinforcing steel.
*The top layer (5 mm minimum thickness) of the concrete shall be mixed with red dye.
QWhen is the duct banks used?
AnsAt cross under paved road, and railroads and when depth is restricted/minimized due to some reasons.
QWhat is the minimum crossing or parallel clearance between direct buried cables or conduits and underground piping?
AnsThe minimum crossing or parallel clearance between direct buried cables or conduits and underground piping, shall be 300 mm.
Cable Testing after Installation
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•Fence test cable ends to ensure personnel safety.
•Preliminary step: ‘Megger’ cable to be tested. Any cable that exhibits low ‘Megger’ readings is questionable and should be cleared before the high voltage DC test is performed.
•Connect output of test set to conductor/terminal to be tested and connect ground terminal of test set to ground.
•Bring DC voltage up to prescribed test level in five equal steps. Raise the voltage at an even rate, so as to reach the required level in not less than 10 seconds. Hold the voltage at each step for 60 seconds. Read and record the leakage current at the end of each hold period.
•Hold the full test voltage for not less than 10 minutes or more than 15 minutes. Read and record the leakage current at 15-second intervals for the first 2 minutes and then every minute for the duration of the test.
•Bring the test voltage control quickly and smoothly to zero. Read and record the voltage remaining on the cable after 30 and 60 seconds. Discharge the cable to ground using a properly terminated resistor stick. When the test set voltmeter indicates zero voltage on the cable, attach a solid ground to the cable and then disconnect the test set and resistor stick.
•Test each conductor/cable in the circuit in the same manner.
•Record all data concerning the circuit and test results.
QHow can we check the condition of the cable insulation in field?
Ans1. The insulation resistance test performed with a megger tester.
2.The DC high potential test or DC hi-pot test
3.The very low frequency high potential test (VLF hi-pot test)
4.The AC high potential test which is performed at power frequency (50 hertz or 60 hertz).
QFor low voltage cable, how much megger voltage requires?
AnsSAES-P-104, megger voltage shall be 1-KV (DC) for one minute.
QFor medium voltage cables how much megger voltage requires?
AnsSAES-P-104, for medium voltage cables (5KV to 35 KV), megger voltages shall be 5-KV (DC).
QWhat kind of cable testing shall be performed at medium voltage (5 kV to 35 kV) cables?
Ans5 kV megger tested before and after backfilling and then DC- high- potential testing after installation and prior to placing in service
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QFor how long time we applied the DC high potential test for 5kv and high rating direct buried cables?
AnsThe DC high potential value shall be 4 kV/1 mm for one minute and not to exceed 10 kV.
QHow we do megger testing of new cables spliced to existing cables?
AnsNew cables to be spliced to existing cables shall be 5 kV megger tested and DC high-potential tested prior to splicing.
After splicing, the new and existing cable combination shall be 5 kV megger tested.
In addition, if the existing cable has been in service for less than five years, the new and existing cable combination shall be high-potential tested.
QWhat kind of test may be applied to determine the condition of old cables?
AnsVery low frequency (VLF) test.
QFor what purpose we applied VLF test?
AnsVery Low Frequency (VLF) test may be applied to determine the condition (dielectric strength of insulation) of old cables.
QFor high voltage cable (69 KV and above) how much voltage requires for Hi-Pot test?
AnsSAES-P-104, Hi-Pot test voltages shall be 192-KV (AC)
QFor what purpose we use high potential test and megger test?
AnsTo check to integrity of the cable jacket.
QHow we check the integrity of overall jacket of direct buried cables rated 5KV and higher?
AnsThe integrity of the overall jacket of direct buried cables rated 5 kV and higher shall be tested by conducting a 5 kV megger and DC high potential test between the cable insulation and ground.
QHow we check the integrity of the overall jacket of direct buried low voltage armored or metal clad cables?
AnsThe integrity of the overall jacket of direct buried low voltage armored or metal clad cables shall be tested by conducting a 500 V megger test.
*IEC 60229 shall be used for HV cable jacket integrity testing.
Cable Separation
QWhat is the minimum separation b/w power and control cables?
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AnsAt (1 kV to 34.5 kV), 300 mm separation is required At (34.5 kV and above), 1 m separation is required
QWhat are the low voltage, medium voltage and high voltage values?
AnsLess than 1000 V Low voltage 1KV to 35 KV Medium voltage
35KV to 69 KV High Voltage 69KV and high voltages Extra high Voltage
*Conduit sealing fittings shall not be used.
*Conduits that cross hazardous location boundaries shall terminate in the open air at both ends of the conduit.
*The cables outside the building shall be direct buried for a distance of at least 2 meters
QDescribe Uninterruptible Power Supply System.
AnsUninterruptible Power Supply (UPS) System shall consist of, but not limited to batteries, battery circuit breaker, rectifier/charger, inverter, static transfer switch, manual bypass line, bypass shielded isolation transformer, output distribution panelboards and management system.
QDescribe Photovoltaic Power System.
AnsSolar Photovoltaic (PV) Power System shall consist of, but not limited to batteries, photovoltaic panels, charge regulator and output distribution panelboards. If AC output is required, inverter (DC/AC converter) shall be included.
Battery Selection, Sizing and Load Determination
*Batteries shall comply with 17-SAMSS-511.
QWhat are the guidelines for the battery selection?
What is the criteria for battery selection?
AnsBattery selection shall be made according to the following guidelines.
a)Lead-calcium or lead low antimony pasted flat plate batteries are generally the most suitable for standby float service applications in an indoor temperature controlled environment. Such applications include electrical substations and UPS systems where shallow moderate cycling is expected. Lead-calcium batteries are not capable of many charge/discharge cycles, i.e., up to 5 cycle operations per year. Nonetheless, lead calcium battery features low current during float charging, and requires equalize charging only as needed. In comparison, lead low antimony batteries are capable of many charge/discharge cycles, but require equalize charging yearly.
b)Tubular plate lead-antimony batteries or lead selenium batteries are suitable for cyclic loads (frequent charge/discharge cycles) and for high current short discharge applications. Due to material retention properties of the tubular construction, such batteries can also be successfully used in locations where frequent battery discharges are anticipated. Lead selenium batteries feature low water loss.
c)Nickel-cadmium batteries are suitable for the applications described in this standard including outdoor non-temperature controlled applications such as remote unattended substations and photovoltaics systems. The batteries are fairly immune to corrosion, are resistant to mechanical and electrical abuse, operate well over a wide temperature range, and can tolerate frequent shallow or deep discharges.
d)The use of valve regulated lead acid (VRLA) batteries shall be limited to applications where flooded batteries cannot be used and when installed in temperature-controlled (25°C) environment.
QWhat are the factors to be considered for selection of batteries?
AnsThe following factors shall be considered in selecting a battery for a particular application:
a)The design life of the battery shall be at least 20 years for flooded lead acid/nickel cadmium batteries, and at least 10 years for VRLA batteries.
b)The design life of the battery shall be based on 25°C.
QDescribe the battery sizing criteria?
Ans1- For applications involving a combination of continuous loads, non-continuous loads and/or momentary loads (such as switchgears), lead acid batteries shall be sized in accordance with the battery sizing worksheets of IEEE 485, and nickel cadmium batteries shall be sized in accordance with the battery sizing worksheets of IEEE 1115, or the equivalent IEC standards as applicable.
2-For photovoltaic (PV) applications involving a combination of continuous loads, non- continuous loads and/or momentary loads, lead acid and nickel cadmium batteries shall be sized in accordance with IEEE or IEC applicable standards.
3-For applications of constant current consumption loads, the battery ampere-hour capacity shall be calculated as follows:
DC Loads:
Battery Ah Capacity @ CBT = L x BT x TC x AF x DF (1)
UPS Loads:
Where:
Battery Ah Capacity @ CBT = Ah capacity of battery at required backup time
Battery Ah Capacity = Ah capacity of battery at C8/C10 and C5, for lead acid battery and nickel cadmium battery, respectively (consult battery manufacturer for the conversion factor to convert Ah @ CBT to Ah @ C8/C10 and C5, for lead acid battery and nickel cadmium battery, respectively)
L = Continuous load current (dc amperes)
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BT = Battery back-up time (hours)
AF = Aging factor (use 1.25 for all batteries)
DF = Design factor (use DF = 1.1 for all types of batteries)
kVA Load = Load designed apparent power (= Actual Load Power Consumption + Future Growth)
PF = Load power factor
No. of Cells = Number of series connected battery cells Eff.Inverter = Efficiency of UPS inverter
VoltageEndCell = Battery cell voltage at end of discharge
TC = Temperature compensation factor (cell size correction factor)
4-If the calculated battery capacity exceeds a manufacturer's standard rating by more than 5%, then the next larger standard battery capacity shall be selected.
5-Paralleling up to 4 sets of battery banks of identical Ah capacity and potential shall be allowed, to achieve the required Ampere Hour capacity.
6-The minimum battery backup time shall be in accordance with Table, and shall be based on the actual load calculation. For applications where the battery backup time exceeds Table 1 requirements, Electrical Equipment Unit, Consulting Services Department shall be consulted.
7-Redundant DC system, which consists of 2 rectifiers/chargers connected in parallel, shall have separate battery banks such that each battery bank shall be sized for 50% of the required total battery backup time as specified in Table.
Table – Battery Backup Times Load
LocationType of LoadPrimary Power SourceBattery Backup Time(1)
In-Plant or In-OfficeAC (UPS)Utility Only60 minutes
In-Plant or In-OfficeAC (UPS)Utility +
Generator(2)30 minutes
In-Plant or In-OfficeDCUtility Only2 hours
In-Plant or In-OfficeDCUtility +
Generator(2)30 minutes
RemoteAC & DCSolar Photovoltaic5 days (120 hours)
Attended
Substation(3)DCUtility +
Generator(2)2 hours
Attended
Substation(3)DCUtility4 hours
Unattended
Substation(3)DCUtility8 hours
Unattended
Offshore SubstationDCUtility12 hours
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8-Battery backup time (battery duration) for emergency or life-critical loads shall be as specified in NFPA 70 and NFPA 101
9-Battery backup time for all security emergency systems shall be per the requirements of SAES-O Standards.
10-No-load losses of redundant systems shall be included in the battery sizing calculations.
11-Switchgear DC system shall be dedicated for loads that are critical and require continuous operation during utility power loss.
12-In-plant DC loads shall not be connected to the battery bank which is dedicated to the UPS system.
13-Substation battery systems shall be dedicated to connected DC loads and shall not be part of a plant UPS or other DC system.
14-The minimum number of series-connected battery cells shall be in accordance with Table or as determined by the calculations. Nonetheless, battery manufacturer's recommended number of cells based on the specified battery backup time shall be followed, if available. Nevertheless, for UPS applications, the number of series connected cells (DC voltage value) shall be selected by the UPS manufacturer.
Required Number of Cells
Number of cells DC
SystemsNumber of Cells
Photovoltaic Systems
Nominal Battery
Voltage (VDC)Lead AcidNickel CadmiumLead AcidNickel Cadmium
1269610
2412181219
4824362438
120/12560/62916095
240/250120/125182120191
360180273NANA
408204309NANA
480240364NANA
15-The maximum number of series connected cells shall be calculated as follows to ensure an optimal and safe DC system voltage and battery recharge voltage:
Max. Number of Cells = Max. Allowed DC System Voltage / Equalizing Volts per Cell
16-Based on the number of cells calculated, the end-of-discharge voltage for each cell shall be calculated as follows to ensure that the system voltage does not fall below the minimum acceptable level:
Voltage Discharge -of – End = Voltage System DC Allowed Min. / Cells of Number
Unless otherwise recommended by the manufacturer, the minimum allowed DC system voltage shall be 87.5% of the nominal system voltage for DC and UPS systems, and 92.5% for Photovoltaic systems.
17-The cell end-of-discharge voltages shall be per Table below: Battery Cell End of Discharge Voltage
Battery TypeGeneral
ApplicationsPV Applications*
Lead-Acid1.65 VPC to 1.75 VPC1.85 VDC
Nickel-Cadmium1.0 VPC to 1.14 VPC1.14 VPC to 1.2 VPC
VPC = Volt Per Cell
Battery Installations
QWhat are the international standard codes for installation of batteries?
AnsAll batteries shall be installed in battery rooms or battery enclosures in accordance with NFPA 70 (NEC), IEEE 484 or IEC 50272-2.
*Batteries shall not be installed in enclosures inside a battery room.
*The minimum battery room ventilation shall be one complete air change every 3 hours, and the temperature inside this battery room is maintained, but never exceed, 25°C.
*Batteries shall not be installed in Class I, Division 1 locations.
*Batteries installed in Class I, Division 2, locations shall be in a building or enclosure made safe by pressurized air. Loss of pressurization shall be monitored in accordance with NFPA 496.
*Working space of at least 1 meter shall be provided in front of each battery rack or enclosure.
*Batteries shall be supplied with covers for all inter-cell connecters and terminals or insulated copper busbars to enhance safety.
QBattery room walls and floor shall be made of what type of material?
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AnsBattery room walls and floor shall be made of concrete construction and finishing.
*Battery room finishing shall not contain drywall (such as plasterboard, wallboard, gypsum board, sheetrock, or gyprock).
*Manned workstations shall not be located in battery rooms.
*Battery rooms shall be provided with enclosed and gasketed (i.e., vapor tight) corrosion resistant lighting fixtures
*Battery room lighting shall be installed to provide a minimum level of illumination of 30-ft candles (300 lux).
*Emergency lighting with illumination level of 10-ft candles (100 lux) shall be installed to operate in the event of loss of mains power supply.
QHow shall be installed the battery room doors?
AnsBattery room doors shall open outward, away from the room, to the outside of the building, and be fitted with door closers and anti-panic (quick-release, quick-opening) hardware. No hasp, padlock, or other device shall be installed which will hinder operation of the emergency door opening devices.
*Doors between battery rooms and other rooms shall not be permitted.
*Potable water facilities shall be provided for rinsing spilled electrolyte in the battery room. Raw water shall not be used (as it is rich of minerals and dissolved solids that may react with the electrolyte). The amount of water supply shall be determined based on a risk assessment of the extreme scenario where the largest battery or electrolyte container gets spilled.
*Provisions for neutralizing the battery electrolyte (acid or alkali) and caustic spillage shall be included in the battery room design.
*Floor drains shall comply with SAES-S-060.
*Sealed valve-regulated batteries do not require floor drains.
*Emergency eyewash facilities shall be provided as required by SAES-B-069.
*Sealed valve-regulated batteries do not require eyewash facilities.
QWith what type of cover the battery room floor shall be covered?
AnsBattery room floor shall be covered with an electrolyte (acid or alkali) resistant, durable, antistatic and slip-resistant surface overall, to a height 100 mm on each wall.
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Where batteries are mounted against a wall, the wall behind and at each end of the battery bank shall be coated to a distance of 500 mm around the battery with an electrolyte resistant paint or tiles.
*A dry type chemical fire extinguisher shall be installed on the outside of the battery room.
*Cabinets or racks shall be provided in the battery room for storing maintenance tools and safety equipment. These cabinets and racks shall be acid or alkaline resistant as applicable.
*Lead acid batteries shall not be mounted in the same room together with nickel cadmium batteries, and vice versa.
*Battery rooms shall be vented to the outside air by forced ventilation to prevent accumulation of hydrogen and to maintain design temperature. The ventilation system is designed such that the hydrogen concentration shall not exceed 1% of the total air volume of the battery room.
*The maximum hydrogen evolution rate for all kinds of flooded batteries is 0.000457 m³/hour (0.016 ft³/hour), per charging ampere, per cell, at 25°C, at standard pressure. The worst condition (the maximum hydrogen evolution) occurs when current is forced into a fully charged battery (overcharge).
*An interlock between the air-handling unit and the high-rate charging switch shall be provided, such that failure of the air-handling unit shall cause the high-rate charging of batteries to stop.
*The ventilation system shall be 100% redundant. Only direct driven exhaust fans shall be used. An interlock with the ventilation system shall be provided to stop the high-rate battery charging if the exhaust fan stops.
*An alternative to interlocking with either air-handling unit or exhaust fans is to interlock the high-rate battery charging system with either an air-flow or air-pressure measuring device, such that ventilation insufficient to the 1% hydrogen limit will cause the high-rate charge to stop.
*Audible and visual alarm shall be installed outside the battery room entrance to annunciate a failure in ventilation for prompt repair.
*The minimum ventilation shall be one complete air change every 3 hours.
*A battery area that meets the above ventilation requirements and the high-rate charge interlock shall be considered non-hazardous. Therefore special electrical equipment enclosures to prevent fire or explosions shall not be required.
*Equipment with arcing contacts shall be located in such a manner as to avoid those areas where hydrogen pockets could form. Electrical equipment shall not be located directly above the batteries and, as a rule, shall have a minimum horizontal separation of 1.5 meters from the nearest cell.
*Temperature in a room that contains batteries shall not exceed 25°C.
*If battery operating temperature increases by 10°C above the 25°C reference, battery design life is reduced by: 50% for lead acid batteries, and 20% for nickel cadmium batteries.
*Return air-conditioning ducts from battery rooms shall be prohibited.
*Lighting fixtures shall be installed at least 300 mm below the finished ceiling.
*Inlets of air-conditioning shall be no higher than the top of the battery cell and the outlets (exhaust) at the highest level in the room. Air inlets and outlets shall be located in such a manner to provide effective cross ventilation over the batteries.
*Batteries installed in a sealed passively cooled shelter shall be located in a separate compartment with a dedicated entrance. All battery cell vents shall be tubed so that hydrogen gas is vented outside the battery compartment.
*Battery racks shall be constructed in accordance with 17-SAMSS-511.
*Battery racks installations shall meet NEC bonding and grounding requirements. Battery racks shall be bonded at both end points to a local supplementary grounding electrode per NEC 250 or EN 50178. Install lug and cable on the steel rack and tighten to ensure ohmmeter reading between each component and a common point on rack frame indicated continuity for proper grounding.
*Stationary batteries shall be installed on open battery racks within a battery room to facilitate proper cooling, routine inspection, and maintenance.
*Either covers for all inter-cell connecters and battery terminals or insulated copper busbars shall be supplied as part of the battery.
QHow much clearance shall be for battery cell to the rack?
AnsClearance from the top of the battery cell highest point to the bottom of the rack above it shall be 350 mm, and airspace between battery cells shall be approx. 10 mm.
QWhat are the requirements for battery enclosures?
AnsBattery enclosures shall be in accordance with the following requirements:
a)The enclosure design shall include a removable lid, secured by quick- release latches, type 316L stainless steel or equivalent. Hinged enclosures shall be designed to open at least 120 degrees to facilitate proper maintenance access.
b)The enclosure base shall be provided with cell supports designed to raise the cells a minimum of 5 cm above the enclosure floor.
c)For indoor use, the battery enclosures and cell supports shall be made of fiberglass reinforced material or steel, with provisions for anchoring to the floor and grounding. The ventilation requirements of paragraph 6.3 shall be complied with.
d)Valve regulated (sealed) lead acid (VRLA) batteries shall be mounted in ventilated indoors enclosures unless installed inside a dedicated battery room, where battery racks are sufficient. VRLA batteries shall not be used for outdoors applications.
e)Battery enclosures for outdoor use shall be made of fiberglass-reinforced material, and shall be completely weatherproof, dust-tight, and rain-tight. The gasket shall be one- piece, heavy-duty black neoprene or Buna nitrile rubber, mechanically attached to the enclosure lip and in continuous contact with the enclosure lid. Minimum protection Class for outdoors mounting shall be NEMA 250 Type 4 (or IEC 60529 IP 65). For offshore outdoors applications, corrosion resistance enclosure NEMA 250 Type 4X (or IEC 60529 IP 65 with corrosion protection) shall be required.
f)The fiberglass material shall meet the flammability rating of UL 94 type V-0.
g)Steel enclosures and grounding lugs shall be coated with an acid-resistant or alkali- resistant (as applicable), chip and scratch resistant, baked powder epoxy or propylene.
h)All hardware shall be 316L stainless steel or equivalent.
i)The enclosure shall have an adequate number of drain openings at the bottom and a minimum of two ventilation openings at the top. The ventilation openings shall be fitted with breather-type plugs to release hydrogen gas without allowing sand/dust to enter the enclosure.
j)Clearance above each battery cell shall be 350 mm, to allow proper air circulation and to permit filling, testing, and replacement of cells. Adequate clearance shall also be maintained in between cells. Air space between battery cells, as well as between the cells and external enclosure walls shall be approx. 10 mm.
k)Enclosures with front access only shall have no more than 2 rows of stepped cells. Enclosures with access from the front and back sides may have a maximum of 4 rows of stepped cells. In the stepped cell arrangement, for vented battery application, cells shall be positioned in such a way that the electrolyte levels markings (both minimum and maximum) can be easily seen.
QWhat are the cable requirements for battery cables?
AnsBattery cables shall be sized for a total voltage drop of less than 3%. Positive and negative battery cables shall be run in the same conduit to prevent inductive heating.
*The positive and negative buses of batteries shall be isolated from earth ground.
*Each battery-based system shall be equipped with properly sized two-pole fused disconnect switch or circuit breaker with an undervoltage release feature to prevent battery discharge beyond the battery's end-of-discharge voltage. The undervoltage device shall disconnect the battery from the load when the battery voltage drops to the end-of- discharge voltage.
*An alarm to indicate the battery circuit breaker open condition (or fused disconnect switch open or blown fuse condition) shall be provided on the charger cabinet or the UPS cabinet. This alarm shall also be annunciated to the main control room DCS or to an area where operators are present.
*The battery circuit breaker open condition (or fused disconnect switch open or blown fuse condition) shall be routed via Standalone or the Supervisory Control and Data Acquisition (SCADA) system or Network Management System (NMS), to the power control center.
*Another alarm to indicate the battery room high temperature shall be annunciated to the main control room.
QWhat is wiring color coding for batteries wiring for grounded and ungrounded systems?
AnsUngrounded Systems for Industrial Facilities Positive: Red
Negative: Black
Battery rack and other equipment grounding conductors: Green Grounded Systems for Special Applications
a)Negative Grounded Systems Positive: Red (ungrounded) Negative: White (grounded)
b)Positive Grounded Systems Positive: Black (grounded) Negative: Red (ungrounded)
*Battery rack and other equipment grounding conductors: Green, or green with yellow stripes
QWhat are the safety equipments shall be provided near stationary batteries?
AnsThe following safety equipment shall be provided near stationary batteries:
a.Safety face shields and goggles
b.Safety aprons
c.Acid resistant rubber gloves
d.Safety shoes
e.Eye washing facilities (refer to SAES-B-069)
f.Neutralizing agent:
-To neutralize lead acid battery:
Mix 0.1 kg bicarbonate of soda to one liter of water.
-To neutralize nickel cadmium battery spillage:
Mix 50 grams boric acid solution to one liter of water.
- Or use other suitable neutralizing agent recommended by the manufacturer for acid electrolyte spillage or the manufacturer of alkaline electrolyte spillage, whichever applicable.
QWhat are the safety signs shall be posted on battery room?
AnsThe following safety signs shall be permanently posted on battery room entrance at a visible location in Arabic and English languages:
a.Sign: “DANGER CAUSTIC/ACID”
b.Sign: “DANGER CAUSTIC/ALKALINE”
c.Sign: “DANGER NO SMOKING”
d.Sign: “EYE PROTECTION REQUIRED IN THIS AREA”