Electrical & MEP Design - Study material.pdf

WHAT IS MEP ??
MEP stands for Mechanical, Electrical & Public Health Engineering which have a vital role in
the building industry.
Mechanical part deals in mechanical design & Construction which includes heating,
ventilating and cooling systems often referred to as HVAC, Vertical Transportation etc.
Electrical part deals in the Electrical design, construction, and practical use of electrical
systems which includes application of Power transmission and Distribution, Lighting
systems, Telecommunication, FAS, CCTV,& PA systems, Home Automation, Building
Automation, Wellness, Parking management etc.
Public Health Engineering (PHE) part usually deals with water distribution and drainage
systems, CP & Sanitary fixtures orientation design, Waste water treatment, solid waste
management, Rain water harvesting, and Firefighting systems etc.

CHALLENGES IN MEP
• The architect designs the structure to meet the needs of the owner or the
Organisation. These needs are usually in the form of the space and shape of the
structure as well as the aesthetic aspects of the building. The functionality of MEP
services is compromised many times.
• The root cause of the MEP coordination problem is not the lack of technology but
the need to apply available technology tailoring to a specific set of business and
technical conditions.
• Limited building space for MEP systems makes the design more complex in
execution and inefficient in operation. This in turn leads to increase the execution
time and more cost with unsatisfied result.

CHALLENGES IN MEP
• In Indian practice most of the time MEP work quality suffers due to -
 Accelerated construction schedule
 Improper work sequence and site clearance.
 Non adherence of Method statement, ITPS and checklist.
 Lack of proper supervision
• MEP systems must satisfy multiple objectives and criteria for design, installation,
testing and commissioning & easy to maintain with least cost.
• Shortage of technically sound & skilled MEP engineers & supervisors who can
understand the specifications , assign responsibility for coordination , checking for
clearances, field conditions, and architectural conditions.
• Shortage of speciality or trade contractor and skilled workforce in MEP.
TATA HOUSING DEVELOPMENT COMPANY LTD.

PROJECT COST HEAD (approx.)
• BUILDER EARTH WORK –5%
• BUILDING FOUNDATION- 10%
• CIVIL CORE & SHELL – 35%
• FINISHES – 20%
• INFRA DEVELOPMENT- 10% ( MEP- 4%)
• MEP BUILDING SERVICES – 20%

MEP COST BREAKUPS
Total MEP Cost: 24% of Project cost
 Capital Goods – 35% of MEP Cost
 Non Capitalised Materials- 45% of MEP
Cost
 Labour- 20% of MEP Cost

LIST OF CAPITAL GOODS
• VERTICALTRANSPORTATION
Elevators & Escalators
• ELECTRICALS
DG, HT/LT Panels, RMU, Feeder Pillars,
Transformers, Bus Ducts, DB, Feeder Pillars, Electrical Motors Etc.
• Plumbing & Mechanicals
STP, WTP, Water Pumps, Fire Pumps, CP/Sanitary Wares,

GENERAL CODES & STANDARDS FOLLOWED:
• National Building Code (NBC)
• National Electric Code (NEC)
• Bureau of Indian Standards (BIS)
• Chief Electrical Inspector to Government (CEIG) & Other Local Statutory
requirements

• State power supply companies.
• IEC, IS, BS

INTRODUCTION : ELECTRICTY GENERATION, TRANSMISSION & DISTRIBUTION

INTRODUCTION
• Specific regulations to be adhered to in the supply and use of electrical energy had
been laid down by the Indian Electricity Act, 2003 and the Indian Electricity Rules,
2003.
• Below is the general schematic for power transmission

3 Phase & 1 phase voltages in House
Electricity Rule – Current can only flow in a circuit only when there is supply voltage and switch is closed on load side.

UTILITY REQUIREMENT & GUIDE LINES:
Categories of Supply: Supply of electricity shall be made available to the consumer under
the following categories :
It varies state to state…
i) Upto 5KVA -1 phase ,230 volts
ii) Upto 140KVA -3 phase ,415 volts
iii) From 141KVA to 5000KVA – 11KV/33KV
iv) Above 5000KVA – 33KV

POWER SANCTION WORK FROM AUTHORITY
Documents required for power sanction work
• Load calculation sheet based on power supply rules and regulation
• SLD of HT & LTdistribution network
• Approved layout Plan & Proposed Layout plan submitted forApproval
• Plot 7/12 abstract/Property Card/ DevelopmentAgreement
• NA Order
• Memorandum of Article ofAssociation
• Photo of Director/ Project Head/Proprietor
• Board resolution for signing authority Papers

POWER SANCTION WORK FROM AUTHORITY
Major points to remember
• Load in KVA/KW as per consultant calculations
• HT and LTdistribution scheme
• Number of Transformers shall be as per consultant recommendationbut
approved by Supply authority also.
• Voltage level shall be checked
• Ring main system shall be checked with 2 different sources forredundancy
• Types of Transformer, e.g. Oil/Dry VPI/Dry CRT etc. to be checked
• Number of single phase, three phase and common area energymeters
• NOC from all municipal authorities like Panchayat, PWD, Highways
authority, municipal water and drainage department, Gas/ Petroleum
companies shall be vendor scope
• PWD/CEIG approvals and site visits on every stage.

TERMINOLOGIES
• Demand Load : The magnitude of maximum electricity supply utilized recorded in kW or
kVA in the time slot of 15 to 30 mins.
• Connected Load : It is the sum of all load connected to the system.
• Diversity Factor : Is the ratio of Demand Load Vs Connected Load.
• Power Factor : The power factor is generally measured by the ratio of kW to kVA
consumed during the specified period. The power factor of an Alternator, Transformer
or any electrical equipment depends on load. Power factor should be as high as possible
and max possible value is 1
• Load Shedding: The load shedding is important term used to reduce the system load.
Load shedding can be done by Voltage Reduction, Frequency reduction, Switching off the
loads. For residential and commercial customers its simply achieved by switching off load
to maintain balance between available power Vs Demand.

Standard MCB ratings
0.5, 1, 3,6, 10,16,20,32,40,63 Amp
Type-A : Lighting Load
Type-B : Resistive Load : Geyser, Oven, Microwave
Type-C : Fridge, Motors, AC,
Type-D : Small Transformers, Large Winding Motors, UPS

LEAKAGE CURRENT EFFECT ON HUMAN BODY
In case of electrical shock, there are few chances that protectivedevice like RCCB may not
operate, in such cases a first stage is to use wooden stick or other insulating material to
disconnect victim from supply, then you can search for location of switch to switch off power.

RESIDUAL CURRENT CIRCUIT BREAKER( RCCB )
Standard RCCB ratings 25,40,63,80
and 100 Amp
30 mA– For house hold appliances
100 mA – For power appliances
300 mA – For Lift and Escalators
Type A : DC, Type AC : AC & Type B : AC+DC

DIFFERENCE BETWEEN RCCB AND ELCB
ELCB(Earth Leakage Circuit Breaker)
RCCB/RCBO(Residual Current Circuit Breaker / Residual Current
Breaker Overload)
Voltage operated device, if voltage across coil is more than 50
Volt, coil will
operate
Current operated device, coil will operate if leakage current
exceed
RCCB rating
Operation based on earth leakage current in enclosure and earth
conductor
Opertation based on unbalance in phase and neutral
Measure voltage between enclosure
and earth and gives tripping command to coil
calculate difference in current between
phase and neutral wire for operation of tripping coil.
Earthing is required
Can operate without earth connection
also.
Monitor phase, neutral and earthing. Monitor phase and neutral only
No protection from over load No protection from over load
Less safety, reliable on eartning quality More reliable and more safe

3 PHASE RCCB OPERATING PRINCIPLES

1 PHASE RCCB OPERATING PRINCIPLES

TYPES OF DITRIBUTION BOARDS
SPN – Single phase and Neutral
TPN – Three phase and Neutral ( Horizontal and Vertical ) TPN
- With 7 Segment DB

7 SEGMENT DB CONNECTION

DITRIBUTION BOARDS
All DB bottom shall be as per Legend (1500/ 1800 mm level from FFL), if Vertical DB are
installed which are more in height, same shall be considered as special case and
architect approvals.

SINGLE PHASE DB CONNECTION

MOULDED CASE CIRCUIT BREAKER ( MCCB )
Standard MCCB ratings
100, 125, 160, 200, 250, 400,630,800, 1000, 1250Amp

AIR CIRCUIT BREAKER ( ACB )
Standard ACB ratings
630,800, 1000, 1250, 1600, 2000, 2500, 3200, 4000, 6300 Amp

VACCUM CIRCUIT BREAKER ( VCB )
Standard VCB ratings 630,1250, 1600 Amp
Standard Voltage Rating – 3.3, 6.6., 11, 22, 33 KV
Standard short circuit rated time – 18.3 /21/25 KA for 1 OR 3Sec

RING MAIN UNIT ( RMU )
Standard RMU ratings 630,1250, 1600 Amp
Standard Voltage Rating – 3.3, 6.6., 11, 22, 33 KV
Standard short circuit rated time – 18.3 /21/25 KA for 1 OR 3Sec

DOUBLE POLE STRUCTURE

4 POLE STRUCTURE

OIL TRANSFORMER

DRY TRANSFORMER ( VPI )

CAST RESIN TRANSFORMER

DIESEL GENERATOR

COMPACT SUBSTATION

LT PANELS

METER DISTRIBUTION BOARD

SINGLE LINE DIAGRAM
SF6/VCB
SWITCHGEAR
ENERGY METER
TRANSFORMER ACB/MCCB
HT
DB
MCB
MCCB/SFU

PVC WIRES
TATA HOUSING DEVELOPMENT COMP

WIRING WORK
Maximum permissible number of 1100 volt grade FRLS PVC insulated wires that
may be drawn into the Conduits:
• Note : Conductor material will be copper upto 16 sqmm above shall be
aluminium.
HT AND LT CABLE TERMINATION
Sizes of wires Nominal Cross
Maximum number of wires within conduit size (mm)
Section Area (Sq.mm.) 20 25 32 40 50 63
1.0 5 10 14 - - -
1.5 5 10 14 - - -
2.5 5 8 12 - - -
4 3 7 10 - - -
6 2 5 8 - - -
10 - 4 5 6 - -
16 - 3 5 6 - -
25 - - 3 4 6 7
35 - - 2 3 5 6

3 PIN SOCKET PHASE CONNECTION VERIFICATION

TATA HOULIGHTENING ARRESTOR EARLY STEAMER-EARLIER

LIGHTENING ARRESTOR
FARADY’S CAGE SYSTEM-NBC 2016

TATA HOUSING MAJOR CHECK POINT
DIESEL GENERATOR
1. Allowed to install at ground and first podium only
2. Proper ventilation and exhaust required
3. Minimum 120 minutes fire rated body and doors
4. Maximum DB level at 1 meter distance shall not exceed – 75 DB
5. CPCB approval is must
6. All DG shall be CPCB II grade only

MAJOR CHECK POINT
LT PANELS
1. Panel height shall not be more than 2100 mm
2. Minimum Clearance around panels shall be 750 mm
3. Spacing between 2 facing LTpanels shall be 2000 mm
4. Panels shall be manufactured ass per approved SLD and GAonly

MAJOR CHECK POINT
DISTRIBUTION BOARD
1. Make of DB shall be as per selection
2. Type of DB – SPN/TPN/7Segment etc.
3. DB Type – Vertical /Horizontal
4. DB switchgear – RCCB, MCB etc.
5. DB Size – Length , Width and depth
6. DB Material selection like sheet thickness, powder coating etc.
7. Installation of DB as per method statement
8. Wiring work as per method statements
9. Testing commissioning shall be done with electronic multimeter and 440 Volt
test lamps
10.All MCB and circuit shall be numbered with ferrules
11.DB schematic shall be stuck on DB cover

MAJOR CHECK POINT
Oil Transformers
• Ensure Oil level is as per recommended by manufacturer
• Ensure Breather and silica gel is in good condition, Pink silica gel is fresh.
• Ensure no leakage are visible at radiators, valves, cables bushingand
conservator tank
• Check temperature gauge
• Check cable tightness
• Ensure proper size earthing is connected

ELECTRICAL SHAFT
• As far as possible it should be in the center of the building for avoiding extra
cable costing
• It shall have fire rated door
• It shall have proper protection from water.
• It shall have 200 mm cut out around three sides and platform ( At least400 mm
in depth and full shaft length ) on entrance side for maintenance works.

TESTING
EARTH RESISTANCE ( AC OPERATION ), ( OHM ) = P2/C2, METER
GIVES DIRECT READING, RESISTANCE VALUE SHALL BE BETWEEN 1- 5 OHM

TATA HOUSING DEVELOPMENT TESTING
DISTRIBUTION BOARD
• First make sure all the switchgears are provided inside DB with asbuilt SLD
• All wiring work is completed
• All earthing work is finished
• Check Phase and neutral Voltages
• Check Insulation resistance by disconnecting all the appliances
• Check DB Earthing and ensure size is proper.
• Check RCCB functions

TESTING
Point Wiring
• Ensure all the socket’s phase connection are provided withswitches only
• Check Voltages across phase – Neutral, Neutral to Earthing for all
sockets points and light points with multimeter
• Check operation of all socket and light point with test lamp,ensure
voltage ratings of test lamp as per circuit voltages
• Check switches are provided as per drawings
• Check earthing of all light and socket points with multimeter andtest
RCCB.

TESTING
Cables
• Insulation resistance test
• HV Test

TESTING
RMU (Ring Main Unit)
• Ensure all cables are disconnected at the time of testing
• Ensure panel operation including earth switch
• Ensure High Voltage test is ok
• Ensure cable HV test is ok before connecting.
• Ensure relay are properly set as per transformer ratings.
• Ensure SF6 gas pressure is as per manufacturer recommendation.

TATA HOUSING TESTING
LT Panel
• Ensure all cables are disconnected at the time of testing
• Ensure panel operation
• Ensure High Voltage test is ok
• Ensure cable 2 KV HV test is ok before connecting any out goingand
incoming cables
• Ensure all MCCB and ACB setting is done as per presentload.

TESTING
Transformer
• Winding resistance test
• Voltage ratio test
• Magnetic balance test
• Polarity test
• Oil and winding temperature gauge test, alarm and trip test for breaker

TESTING
BUS DUCT
• HV Test
• Continuity test
• Connection tightness test or micro ohm meter test

TESTING
RCCB
• Check RCCB tripping by shorting neutral and earth
• Check RCCB by test buttons

POINTS TO REMEMBER
• All the Electrical point functionality inside apartment shall be tested with Test Lamp before
handing over to customer. Test lamps shall be 2 nos in series or with multimeter.
• During DB testing DB dressing, Tightness of connections, Switchgear rating as per SLD should
be checked.
• Before laying any of the power cable, electrical supervisor should first ensure that IR value and
continuity of cable is satisfactory.
• If circuit breaker contact looks red hot, then the reason might be Over load / Loose Contact /
Wrong size of cable selection.
• DOL (Direct On Line) starter is advisable up to 7.5 hp motor rating.
• Wall chasing shall be done with Groove cutting machine.
TATA HOUSING DEVELOPMENT COMPAN

• Keeping HT substation and Transformer room near to load is Economical Electrical Design.
• Best protection is provided by HRC fuse in case of Short Circuits.
• The effect of electric shock on human, body depends on Voltage, Current & Duration of
contact.
• A tap changer is used on a transformer for adjusting secondary voltage.
• Fuse wire protection system is usually not used beyond 100 A.
• SF6 is the cheapest switchgears for high voltage application for residential projects.

POINTS TO REMEMBER
• Before procurement of transformer, MEP manager should check weather supply companies
approval is available.
• All the DG set manufactured shall comply to the CPCB II rating.
• Variation in PO shall be raised after shop drawing approval.
• RCCB is used to protect us from the leakage current & for Household application leakage
current rating of ELCB should be 30 mA.
• DB earthing shall be tested by Test Lamp and Multimeter.
• For jointing earth strip, minimum 75mm overlapping is advisable.
• Minimum 1 meter length of extra cable is advisable to be kept inside LT panels.
• Earthing work shall be carried out as per Earthing Schematics.

POINTS TO REMEMBER
• Before Commissioning of HT Panel, Cable termination box and cable tightness Cable Bushing,
Gas pressure ETC to be checked.
• 1 Ton AC is equal to 1.4- 1.6 KW
• Current is decided by Load.
• As built drawing shall be made after site execution is over, same is required for records to
estate team and our valuable customers, any modification become easy when such records are
available

Always use proper tools for chasing
cutting etc. Use Groove cutting
machine
Don’t use big chisel and hammer for wall
cutting.

DO’s & DON’T’s
DO’s DON’T’s
Always use safety goggle and ear
guard while cutting and chasing of
wall.
Don’t take risk with your ears and
eyes.

DO’s DON’T’s
Use proper color conduit as
mentioned in the submittal.
Don’t use single color conduits for
slab Conduiting works.

DO’s DON’T’s
DB box should be flushed with
finished wall.
Don’t install DB with gap.

DO’s DON’T’s
Use PVC solvent only as recommended by
pipe manufacturer.
Don’t use non approved solvent for pipe
jointing.

DON’T’s
Used Indian Standard sockets only.

Electrical & MEP Design - Study material.pdf

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