Electrical Thumb Rules-(Part 7, 8 & 9)

Overhead Conductor /Cable Size:

Voltage	Overhead Conductor	Cable Size
33 KV	ACSR-Panther/Wolf/Dog , AAAC	150,185,300,400,240 mm2 Cable
11 KV	ACSR-Dog/Recon/Rabbit , AAAC	120, 150,185,300 mm2 Cable
LT	ACSR-Dog/Recon/Rabbit , AAC,AAAC	95,120, 150,185,300 mm2 Cable

 Transmission / Distribution Line:

Span	Height of Tower
400KV=400 Meter	400KV=30Meter (Base 8.8 Meter)
220KV=350 Meter	220KV=23Meter (Base 5.2 Meter)
132KV=335 Meter	220KV Double Circuit=28 Meter
66KV=210 Meter	66KV=13Meter
Conductor Ampere	Voltage wise Conductor
Dog=300Amp	400KV=Moose ACSR=500MVA Load
Panther=514Amp	220KV=Zebra ACSR=200MVA Load
Zebra=720Amp	132KV=Panther ACSR=75MVA Load
Rabbit=208Amp	66KV=Dog ACSR=50MVA Load
Moose=218Amp

 Type of Tower:

Type	Used	Angle/Deviation
A	Suspension Tower	Up to 2°
B	Small Angle Tower	2° to 15°
C	Medium Angle Tower	15° to 30°
D	Large Angle / Dead End Tower	30° to 60° & Dead End

 Tower Swing Angle Clearance (Metal Part to Live Part):

Swing Angle	Live Part to Metal Part Clearance (mm)
	66KV	132KV	220KV	400KV
0°	915mm	1530mm	2130mm	3050mm
15°	915mm	1530mm	2130mm	–
22°	–	–	–	3050mm
30°	760mm	1370mm	1830mm	–
44°	–	–	–	1860mm
44°	610mm	1220mm	1675mm	–

 Cable Coding (IS 1554) A2XFY / FRLS / FRPVC / FRLA / PILC)

A	Aluminium
2X	XLPE
F	Flat Armoured
W	Wire Armoured
Y	Outer PVC Insulation Sheath
W	Steel Round Wire
WW	Steel double round wire Armoured
YY	Steel double Strip Armoured
FR	Fire Retardation
LS	Low Smoke
LA	Low Acid Gas Emission
WA	Non Magnetic round wire Armoured
FA	Non Magnetic Flat wire Armoured
FF	Double Steel Round Wire Armoured

 Corona Ring Size:

Voltage	Size
<170 KV	160mm Ring put at HV end
>170 KV	350mm Ring put at HV end
>275 KV	450mm Ring put at HV end & 350 mm Ring put at Earth end

 Load as per Sq.Ft:

Type of Load	Load/Sq.Ft	Diversity Factor
Industrial	1000 Watt/Sq.Ft	0.5
Commercial	30 Watt/Sq.Ft	0.8
Domestic	15 Watt/Sq.Ft	0.4
Lighting	15 Watt/Sq.Ft	0.8

  Size of Ventilation Shaft:

Height of Building in meter	Size of ventilation shaft in sq meter	Minimum size of shaft in meter
9.0	1.5	1.0
12.5	3.0	1.2
15 and above	4.0	1.5

Electrical Thumb Rules-(Part-8)

OCTOBER 1, 2013 10 COMMENTS

Accuracy Class of Metering CT:

Metering Class CT
Class	Applications
0.1 To 0.2	Precision measurements
0.5	High grade kilowatt hour meters for commercial grade kilowatt hour meters
3	General industrial measurements
3 OR 5	Approximate measurements

 Accuracy Class Letter of CT:

Metering Class CT
Accuracy Class	Applications
B	Metering Purpose
Protection Class CT
C	CT has low leakage flux.
T	CT can have significant leakage flux.
H	CT accuracy is applicable within the entire range of secondary currents from 5 to 20 times the nominal CT rating. (Typically wound CTs.)
L	CT accuracy applies at the maximum rated secondary burden at 20 time rated only. The ratio accuracy can be up to four times greater than the listed value, depending on connected burden and fault current. (Typically window, busing, or bar-type CTs.)

 Accuracy Class of Protection CT:

Class	Applications
10P5	Instantaneous over current relays & trip coils: 2.5VA
10P10	Thermal inverse time relays: 7.5VA
10P10	Low consumption Relay: 2.5VA
10P10/5	Inverse definite min. time relays (IDMT) over current
10P10	IDMT Earth fault relays with approximate time grading:15VA
5P10	IDMT Earth fault relays with phase fault stability or accurate time grading: 15VA

Electrical Thumbs Rules (Part-9)

MARCH 15, 2014 8 COMMENTS

Load in Multi-storied Building (Madhyanchal Vidyut Vitran Nigam)
Type of Load	Calculation	Diversity
Domestic  (Without Common Area)	50 watt / sq. meters	0.5
Commercial  (Without Common Area)	150 watt / sq. meters	0.75
Lift, Water Pump, Streetlight ,Campus Lighting ,Common Facilities,	Actual load shall be calculated	0.75

Load in Multi-storied Building (Noida Power Company Limited)
Type of Load	Calculation	Diversity
Domestic (Constructed area)	15 watt / sq. Foot	0.4
Commercial(Constructed area)	30 watt / sq. Foot	0.8
Industrial (Constructed area)	100 watt/ 1 sq. Foot	0.5
Lift, Water Pump, Streetlight ,Campus Lighting ,Common Facilities,	0.5Kw / Flat
Voltage Drop: 2% Voltage drop from Transformer to Consumer end.
T&D Losses: 2% T&D Losses from Transformer to Consumer end.

Approximate % Cost or Sq.Foot Cost
Project Item	% of Total Project Cost	Rs per Sq.Foot
Articheture (Consultancy)	0.7%	13.1 Rs / Sq.Foot
Structural (Consultancy)	1.2%	21.8 Rs / Sq.Foot
Service Design (Consultancy)	0.4%	7.2 Rs / Sq.Foot
Fire Fighting Work	1.3%	23 Rs / Sq.Foot
Electrical Work (Internal)	4.1%	76 Rs / Sq.Foot
Lift Work	4.4%	82 Rs / Sq.Foot

Street Light Costing (CPWD-2012)
Fluorescent Lamp	95 Rs/Sq.Meter
With HPMV Lamp	130 Rs/Sq.Meter
With HPSV Lamp	165 Rs/Sq.Meter
Electrical Sinage	85 Rs/Sq.Meter

Other Electrical Cost
Area Required for Solar Light	10 Watt/Sq.Foot
Solar Power Installation	1.5 Lacs Rs/1Kw
HVAC Cost	18 Watt/Sq.Foot

Distribution Losses (Gujarat Electricity Board)
Voltage (Point of Injection)	At 11 KV	Point of Energy Delivered
11KV / 22KV / 33KV	10%	1082%
400 Volt	–	16.77%

Rate Analysis (CPWD-2012)
Description	Amount
Sub Station Equipment	7000 Rs/ KVA
D.G Set with installation	1000 Rs / KVA
UPS with 30min Breakup	20000 Rs / KVA add 8000 Rs / KVA additional each 30 min
Solar Power Generation	1.25 Lacs / KW
Solar Water System (200Liter/Day)	46000 Rs
Solar Water System (300Liter/Day)	64000 Rs
Solar Water System (1000Liter/Day)	210000 Rs
Central AC Plant	75000 RS / Ton
VRF / VRV System	55000 Rs / HP
Air condition System	11000 Rs / Ton
CCTV System	300 Rs / Sq Meter
Access Control system	200 Rs / Sq Meter
Hydropenumatic Water system	2000 Rs / LPM
Building Management System	300 Rs /  Sq Meter add 100 Rs / Sq Meter additional area beyond 10000 Sq Meter

Rate Analysis (Rs per Sq. Meter) (CPWD-2012)
Work	Office/College/Hospital	School	Hostel	Residence
Fire Fighting (with Wet Riser)	500	500	500	500
Fire Fighting (with Sprinkler)	750	750	750	750
Fire Alarm (Manually)	–	–	–	300
Fire Alarm (Automatic)	500	500	500	500
Pressurized  Mechanical Ventilation	650	650	650	650

Rate Analysis (% of Total Project Cost) (CPWD-2012)
Work	Office/College/Hospital	School	Hostel	Residence
Internal Water Supply & Sanitary	4%	10%	5%	12%
Internal Electrical Installation	12.5%	12.5%	12.5%	12.5%

Lift Speed (Indian Army Manual)
No of Floor	Lift Speed
4 to 5	0.5 to 0.7 meter/Sec
6 to 12	0.75 to 1.5 meter/Sec
3 to 20	1.5 to 2.5 meter/Sec
Above 20	Above 2.5 meter/Sec

Lift  Details (CPWD-2012)
Type of Lift	Persons	Weight	Speed  M/Sec	Travel	Price	Add Rs /Floor
Passenger Lift	8 Person	544 Kg	1.0	G+4	18 Lacs	1.25 Lacs
Passenger Lift	13 Person	844 Kg	1.5	G+4	22 Lacs	1.25 Lacs
Passenger Lift	16 Person	1088 Kg	1.0	G+4	28 Lacs	1.50 Lacs
Passenger Lift	20 Person	1360 Kg	1.5	G+4	30 Lacs	1.50 Lacs

MCB Class according to Appliances
Appliance	Capacity / watt	MCB Rating	MCB Class
Air Conditioner	1.0 Tone	10A	C Class
	1.5 Tone	16A	C Class
	2.0 Tone	20A	C Class
Freeze	165 Liter	3 A	C Class
	350 Liter	4 A	C Class
Oven /Grill	4500 Watt	32 A	B Class
	1750 Watt	10 A	B Class
Oven / Hotplate	750 Watt	6 A	B Class
	2000 Watt	10 A	B Class
Room Heater	1000 Watt	6 A	B Class
	2000 Watt	10 A	B Class
Washing Machine	300 Watt	2 A	C Class
	1300 Watt	8 A	C Class
Water Heater	1000 Watt	6 A	B Class
	2000 Watt	10 A	B Class
	3000 Watt	16 A	B Class
	6000 Watt	32 A	B Class
Iron	750 Watt	6 A	B Class
	1250 Watt	8 A	B Class
Toaster	1200 Watt	8 A	B Class
	1500 Watt	10 A	B Class