Sunday 21 June 2015

Electrical Wiring and Test Certificate

House wiring is required for new construction and also for repairing / modification / up gradation in future. The completion of job should not be treated as horse play. In case of defects in electrical wires it can cause fire in house and may even take human life in some cases.
Wiring test certificate

How to ensure good electric works? 
  1. A professional or experienced electrician should be hired for electrification job. All electric works and installations should comply with latest Indian Electricity Acts and Rules in all respects.
  2. Make sure that electrician has calculated total load from various items that would be used in the house. Whether he lays wires that are capable of taking total load. 
  3. All materials used in electrical fittings should be of approved and from a reputed manufacturer as per ISI specifications.
  4. It is the observation that electricians are careless while putting right load bearing wires for a purpose and these wires get burnt at the movement when entire load is put on wires.
House Wiring tips as per ISI Specification
  • The wiring should be carried out for power distribution systems with main and branch distribution boards to convenient centres distinguishing power circuit and lighting circuit separately. 
  • All conductors should run, as far as possible along walls and ceilings, so as to be easily accessible and capable of being thoroughly inspected.
  • We should avoid wiring on above ceiling.
  • Medium pressure wiring and all associated apparatus should comply with specification.
  • The numbers of points in light circuits should not exceed 10 or the total load on circuit should not exceed 800 watts.
  • One circuit can be explained as one connection from electrical meter or main fuse circuit.
  • For power wiring circuit the numbers of points in a circuit should not be more than 2 and the size of wire is 1.5 mm square copper only.
  • Switch boards should be fitted at a height of approximately 1.2 meter.
  • Horizontal run of wiring should be at a height of 3 meter.
  • Earth wire should be 14 SWG in case of copper and 4 mm square in case of aluminium.
  • Fuse wire should be connected to phase wire only.
  • Connect a neutral link in neutral wire.
  • Connect all switches in phase wire.
  • Use 4 sqmm copper wire for power point as for AC and heater.
  • Power wiring is not les than 2.5 sqmm copper wire.
  • Follow colour code even in single phase, Power-R/Y/B colour, neutral-black, earthing-green.
  • Inverter or emergency wire colour may be white /gray for clear identification.
  • An ELCB is essential of 30mA rating for safety reason.
  • Don’t forget to test ELCB to test monthly for working.
  • Minimum size of earth wire for light circuit is 1 mm square for copper and 1.5 mm square for aluminium.
  • One should avoid using aluminium wire for house wiring or where it is less than 6 sqmm due to breaking easily.
  • Contractor or electrician should be asked to make test certificate.


What is the Electrical Installation Certificate?
BS 7671 (IEE Wiring Regulations): It is the safety Certificate which confirms that the electrical installation work to which it relates has been designed, constructed and tested. It is a legal requirement.
IS 732 (1989): Code of Practice for Electrical Wiring
The Electrical Installation Certificate is required for:
- New installations
- When a new circuit or circuits are installed to an existing installation
- The changing of a consumer unit (distribution board)
- When a circuit is altered and the alteration requires changing of the protective device.
After the initial verification, once the full inspection and testing procedure has been carried out, an Electrical Installation Certificate is completed.
To be valid the Electrical Installation Certificate must be accompanied by a: 
- the Schedule of Inspections
- the Schedule of Test Results.
The original document must be given to the "person ordering the work" and a copy should be kept by the electrician who completed the inspection and testing.



TYPICAL TEST CERTIFICATE 
 Dated: xx.xx.xxxx
Form of Completion Certificate
I/We certify that the installation detailed below has been completed  by me/us and tested and that to the best of my/our knowledge belief it complies with Indian Electricity Rules, 1956, Electrical installation at  (location)---------   -----------------------                                 _________________________, ----- Voltage and system of supply.
1. Particulars of work:
a) Internal Electrical Installation
No.                         Total Load                           Type or system of wiring
 i) Light point ii) Socket point
a) 5pin 5 Amp.
 b) 6 pin 15 Amp.
b) Others
2. Earthing: -
 i) Description of earthing electrode
 ii) Number of earth electrode
 iii) Size of main earth lead
3. Test results :
 a) Insulation resistance
i) Insulation resistance of the whole ystem of conductors to earth
ii) Insulation between the phase conductor and neutral                                Megaohms
Between Phase R and neutral                                                                    Megaohms
Between Phase Y and neutral                                                                    Megaohms
Between Phase B and neutral                                                                    Megaohms
iii) Insulation resistance between the phase conductors in case of polyphase supply.
Between Phase R and Phase Y                                                                   Megaohms
Between Phase Y and Phase B                                                                   Megaohms
Between Phase B and Phase R                                                                   Megaohms
b) Earth continuity test- Maximum resistance between any point of the earth continuity conductor including metal conduits and main earthing leads Ohm c) Earth Electrode Resistance Resistance of each earth electrode i)……………..Ohm ii)…………….Ohm iii)……………Ohm iv)……………Ohm


 Signature                                                                                                      Signature 
 Name of client rep.                                                                                   Name of the Supervisor
M/s-----                                                                                                    M/s-----(seal of company.)

Wednesday 17 June 2015

Earth Electrode life

Earth Electrodes are selected on the basis of their resistance to corrosion. The other major faction in selection is cost parameter. The cost of a product is seen as the initial up front price, but the real cost is determined by the serviceable life of the ground rod.
Galvanized Iron pipe rods are one of the cheapest electrodes available. However, they are not the most cost effective since they have a relatively short service life.
Earth electrode life
Solid copper and stainless steel rods have a long service life. However, they are considerably more expensive than GI pipe  rods. In addition to this, solid copper rods are not suited to deep driving into hard ground due to the likelihood of bending.
copper bonded ground rods is recommend over copper clad electrodes because the copper coating will not slip or tear when driven nor will it crack if the rod is bent.
Copper bonded earth rods feature high resistance to corrosion, provide a low resistance path to ground and have good characteristics for deep driving.
The Stainless Steel Option:
It is important to note that certain soils and land fill areas may not be compatible with copper. In these situations, stainless steel represents a better option.
Stainless steel earth rods may also be an alternative, where structures or components, such as steel towers, poles or lead sheathed cables are in close proximity to an array of ground electrodes.
In these circumstances, consideration must be given to the consequence of galvanic corrosion. The high cost of stainless steel rods prohibits their widespread use.  
earth electrode life 

Sunday 14 June 2015

energy calculation of electrical appliance

Know your electricity consumption and help saving electricity
The table below tells you how much energy you consume through various devices. You can save a lot of energy for the nation and cut your electricity bills by switching off the devices which are not required.
Some Ready Calculations
Device (Capacity & Size)
Wattage
Monthly Electricity Consumption (kWh)
One Unit od power will be consumed when you run the device for…
One hour/day
Six hours/day
Bulb
25
0.75
4.5
40 hrs.
40
1.2
7.2
25 hrs.
60
1.8
10.8
16 hrs. 40 min
100
3
18
10 hrs
CFL
5 watt
7
0.21
1.26
143 hrs.
9 watt
11
0.33
1.98
90 hrs
11 watt
13
0.39
2.34
77 hrs.
25 watt
27
0.81
4.86
37 hrs.
Fluorocent 

Tube Lights 48″
with Copper choke
55
1.65
9.9
18 hrs. 11 min.
with Electronic choke
35
1.05
6.3
28 hrs. 11 min.
Night Lamp
15
0.45
2.7
66 hrs. 40 min.
Ceiling fan
36/48″
50
1.5
9
20 hrs.
56″
60
1.8
10.8
16 hrs. 40 min.
60″
71
2.1
12.6
14 hrs. 17 min.
Table Fan 12″ / 16″
40
1.2
7.2
25 hrs.
Electric Iron
Domestic
450./700
13.5 to 21
81 to 126
2 hrs. 13 min to 1 hr. 25 min.
Dhobi
1000
30
180
1 hr.
Immersion Iron
1000
30
180
1 hr.
Geyser
Storage 15-50 lit
2000
60
360
30 min.
Instant
3000
90
540
20 min.
AC
1 ton
1400
42
252
43 min.
1.5 ton
1800
54
324
33 min.
Air Cooler
170
5.1
30.6
5 hrs. 53 min.
Refrigerator
Small
225
2 unit/day
Big
300
4 unit/day
Toaster
800
24
114
1 hrs. 15 min.
Hot Plate
1000/1500
30 to 45
180 to 360
1 hr. to 40 min.
Elecric Kettle
1000/2000
30 to 60
180 to 360
1 hr. to 30 min.
Mixer-Juicer (Big)
450
13.5
81
2 hrs. 13 min.
Washing Machine
Automatic
325/1000
3 hrs. 5 min. to 5 hrs.
Semi-Autometic
200
6
36
5 hrs.
Vacuum Cleaner
700-750
21 to 22.5
126 to 135
10 hrs. 26 min. to 1 hr. 20 min.
Radio
15
0.45
2.7
66 hrs . 40 min.
Tape Recorder
20
0.6
3.6
50 hrs.
TV
60 to 120
1.8 to 3.6
10.8 to 21.6
16 hrs. 40 min. to 8hr. 20 min.
Video
40
1.2
7.2
25 hrs.
Mosquito Repellant
5
0.15
0.9
200 hrs.
Water Purifier
25
0.75
4.5
40 hrs.
Computer
100 to 150
3 to 4.5
18 to 27
10 hrs to 6 hrs. 40
min.

Courtesy : http://www.powericaltd.com

One Nation, One electrical License

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