ELECTRICITY MYTH AND FACT

Myths & Facts of Electricity

Electricity Myths Can be a Killer


There are lots of juicy myths on various subjects like earthquake, eclipse, etc. in almost every nations; but fact is that electricity myths are not jukes or fun, just a little mistake can cause of severe electrical shock, burn or even death!!

If you don’t sure or without advice from electrician, do not believe any myth on electricity. To know the fact contact your nearest electricity utility company or any electrical professional or electrician.

Our post on electricity myth and fact may not be juicy or folky but  will give you some important information that will help to use safe electricity as well as save your electricity.

Myths and Facts on Electrical Safety

Myth: Power lines are insulated, no chance to shock.                               
Fact: Most of the powerlines are not insulated and insulated powerlines also can lost their insulation any time very easily.

Myth:This line is safe because it is not high voltage line.
Fact: Actually high voltage is not required to kill anyone, ampere flowing through the body is enough to kill. Our house using about 100 ampere where 1 ampere shock is enough to fatal hart irregularities.

Myth: Birds landing on electric wires, so wires are safe to touch.
Fact: No, Birds touching only live wire and not touching any ground path to complete the circuit, that’s way birds are not electrifying.

Myth: Fallen conductor is shut off, no electricity presence.
Fact: Not true always, if it is fallen on poor conductive materials like dry earth  or grasses, bitumen etc.

Myth: Live conductor make sparks; so no spark fallen wire is safe.
Fact: Actually sparks happen where there is loos contact, with firm contact sparks not happen.

Myth: As the ladder is not metalic, so it can rest on live electric line.
Fact: No, If you don’t know the material property and hazard risk level, don’t use ladder rest on powerline.

Myth: Bamboo and wood are not conductor.
Fact: Actually dry bamboo and wood are poor conductor, but witty or green bamboo and wood are conductive that may cause sever shock.

Myth: Rubber is insulator, so rubber gloves and shoes are safe to touch electricity.
Fact: Only 100% pure rubber or especially electrical insulation type rubber is good insulator, otherwise typically mixed materials used rubber gloves or shoes are not good insulator.

Myth: Trimming tree and touching on electric line for a short moment of time is not dangerous.
Fact: No, never do this. Call the nearest power utility department.

Myth: Digging a sallow/ few deep in ground, no chance to reach to underground cable.
Fact: Underground cable may be in upper layer than you are thinking, take advice from professional.

Myth: Electric shock be come only for touching the live wire, closed to it is not danger.
Fact: Closed to high voltage live line is as danger as touching. Current can jump or arc. Keep safe distance from electric line always, at least 3 meters. 


This is not a myth

Myths and Facts on Electric Bill

Myth: It takes more energy to turn on the switch for light bulb or fan, so better to keep it on to save the electricity bill.
Fact: No! there are no extra electricity used for switch ON/OFF. Turning the light/fan off saves the electricity consumes. Appliances consume small amount of energy while on standby mode, better to unplug/switch off.

Myth: Keep the AC running whole day in high setting is better than to run at end of the day while room is heated, this way saves energy.
Fact: Not a wise decision, cooling hot room down takes less energy than running the AC whole day in any setting.

Myth: Same device takes more energy at 240V system than 110V system.
Fact: No, energy measured by unit in watts which comes from multiplication of voltage and current. In electrical system power/watt salways same, if voltage increase the current decreases proportionally and vise-versa. So, wattages remain same and so the cost.

Myth: Faulty wiring is cause of pay more electric bill than that used.
Fact: Yes, if wiring system is with small leakage that will not lead your line shut off, but some leakage current always passes out from the circuit even all the switch off , that you not used but counted on energy meter for billing at end of the month.

Myth: Mis-wiring or used undersized wire causes more electric bill.
Fact: Yes, using undersized cable in house wiring is cause to pay more electric bill than that used. If the cable/wire size is not enough to carry the current safely, wire be come heated and extra electrical energy uses as dissipated heat energy is cause of extra electric bill. 

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Electricity Kite


Franklin wrote an article for the Pennsylvania Gazette in 1752, article tried to proof theoretically the existence of electricity. Franklin choose a cloudy and stormy day to do his experiment, flying a kite to reach near to lightning. Franklin kite was silken, complete with lightning road, a key sagging on the end of string. When lighting struck the Franklin kite volt travel through the string and charged the metal key. Franklin touching the key got shock and proved the existence of electricity.


Last Line: Enjoy the myths but remember the fact before come near to electricity.

What is the Advantages and Disadvantages of D.C. and A.C. Transmission System?

What is the Advantages and Disadvantages of D.C. (Direct Current) and A.C. (Alternating Current) Transmission System?




What is the Advantages and Disadvantages of D.C. (Direct Current) and A.C. (Alternating Current) Transmission System?


The electrical energy transmission can be transmitted either by means of DC- Direct Current or AC- AlternatingCurrent each system has its own advantages and disadvantages. From that point of view, we want to discuss today the technical advantages and disadvantages of the two electrical energy transmission systems for of electric power network.


D.C. Energy Transmission System


From the couple of years past, engineers in transmission sector are rethinking the DC electric transmission system. DC electric power transmission has been receiving the active consideration due to its numerous advantages as bellow:

Advantages of DC Electrical Energy Transmission System.


The high voltage DC energy transmission has the following advantages over the high voltage AC energy transmission system.


(i) DC system requires only two conductors comparing to three for AC transmission;


(ii) In DC transmission system there is no presence of inductance, capacitance, phase displacement and surge problems comparing AC transmission system;


(iii) In DC electric transmission line has better voltage regulation comparing AC system due to the absence of inductance. For a particular same load the voltage drop in a DC transmission line is less than the AC;

(iv) The total conductor cross section of the transmission line is utilized due to their no skin effect in a DC system;

(v) For the same working voltage, the potential stress on the insulation is less in case of DC system than that in AC system. So, a DC line requires less insulation;

(vi) There in a DC line has less corona loss and reducedinterference with communication circuits;

(vii) The high voltage DC transmission is free from the dielectric losses, particularly in the case of cables;

(viii) In DC transmission system, there are no stability problems and synchronizing difficulties comparing AC system.

You may read the another article to know details about D.C. transmission and distribution:


HVDC Transmission and Distribution System Network



Disadvantages of DC Electrical Energy Transmission System

The high voltage DC energy transmission has the following dis advantages over the high voltage AC energy transmission system.

(i) Due to commutation problems the electric power cannot be generated at high DC voltage that is one of the disadvantage of DC system;


(ii) Stepped up or stepped down in electric energy transmission system is an important factor, but in the DC voltage cannot be stepped up for transmission of power at high voltages;


(iii) The DC switches and circuit breakers have their own limitations.

A.C. Energy Transmission System

Now-a-days, most of electrical energy transmission system is in Alternating Current or AC system. Exclusively generation, transmission and distribution system is popular in all over the world.

Advantages of AC Electrical Energy Transmission System

(i) It is easy and can be generated at high voltages AC electric power system;

(ii) The maintenance of AC sub-stations is easy and cheaper than DC transmission system;

(iii) The AC voltage can be stepped up or stepped down by transformers with ease and efficiency that is not possible in DC energy transmission system. This permits to transmit power at high voltages and distribute it at safe potentials in AC electric transmission system.

Disadvantages of AC Electrical Energy Transmission System

(i) An AC transmission conductor copper is required more copper than a DC transmission line;

(ii) The construction of AC transmission electric line network is more complicated than a DC transmission electric line network;

(iii) Due to skin effect in the AC system, the effective resistance of the line is increased;

(iv) The AC line system has capacitance. Therefore, there is a continuous loss of power due to charging current even when the line is open.

Cable Pulling & Jointing Tools and Equipment

Cable pulling, Jointing and Termination  equipment play very important rules to ensure a quality work to operate safe and long-life operation. Cable pulling tools make to easy and safe cable laying, less cable sheath or screen damage/scarce, applying pulling tension correctly and spacing cable in trench or duct properly. Cable Joint and Termination tools are very much special for cable jointing and  cable sealing end termination.

How Use Cable Pulling Tools & Prepare Cable Trench?


Before laying cable, cable trench or cable duct must prepare as per site requirement. Cable ducts or trench measurement will not same for all, depending the voltage rating, cable size, laying location and others vicinity factors cable ducts or trenches depth and width varies.
 
According to low, medium and high voltage cable, the open trench depth and width are varies. Usually the higher the voltage range the higher the depth and width of cable trench.


At the bending point, the cable trench must be followed adequate size as per cable manufacturer recommendation, means trench width must be sufficient to bend the cable without overexcite mechanical stress to cable. The cable bending diameter depends on cable flexibility, and cable flexibility depends on cable constructed materials.  Corrugated aluminum metallic sheath  is used to get more flexibility for high and extra –high voltage cable.
Cable trench  should be sufficient to movement the installer to install the cables and allow the cables to be installed within specified cable pulling dimensions and without damaging the cable sheaths considering bending radii.

 Equipment Required For  Cable Laying In Trench 

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Key equipment for cable laying in trench with brief description are as below:
  1. Cable Winch
  2. Winch Wire Rope
  3. Cable Pulling Swivel
  4. Cable Socks
  5. Cable Rollers
  6. Corner Rollers
  7. Draw Off Rollers
  8. Cable Drum Trailer


Cable Pulling WinchCable Winch– A cable winch is a mechanical device that is used to pull in (up) the cable   or let out the cable or to adjust the cable pulling tension. It consists of a spool and attached hand crank.

During cable the cable  winch is placed the end of the cable trench that provides smooth and controlled actual pulling of the cables through the trench. There are various cable winches depending the types of cable to pull, like- telecommunications, heavy power cables and lightweight small power cabling etc.




Winch Wire Rope– Winch wire rope is nothing but a metal wire rope twisted into helix formatting a composite rope. Larger diameter winch rope consists of multiple number of wire strands to provide larger pulling strength.
Winch Wire Rope














During cable pulling in a cable trench the winch wire rope is attached to the cable  end eye bolt to be pulled through the winch rope.  This winch wire rope allows for heavier cables to pull through the trench and gives extra strength.


Cable Pulling SwivelCable Pulling Swivel–The cable pulling swivel is a connecting device that connect between the grip (cable) and the pulling rope or winch wire. The cable pulling swivel is designed such a way that used to allow the winch wire to rotate when being pulled and avoid kinking or twisting the cable core and protect from damages.

The impertinency to select the cable pulling swivel is to mind the maximum pulling capacity at or above the pulling-force of the cable puller.

Depending the cable types and pulling purposes swivel or connector may different types, like- Clevis pin, Line swivels, Rope connectors, Breakaway swivel and connectors,  shackle and connectors, Wire rope bridle slings, etc.



Cable Pulling Shocks
Cable Socks–Cable pulling sock is a such kind of cable installation tools that high tensile galvanized steel wire shock than ensure an efficient method of supporting for cable pulling.

Cable socks are also called as cable grips or cable shocking. This is the most handy efficient tools to pull the cable in trenches, ducts or buildings. This is high tensile galvanized steel wire, also available in stainless steel or Kevlar constructed.

Cable Roller– Cable roller is simple cable pulling tools that used to roll  or pull the cable on it. It is placed 3 to 4 m apart and at corners to allow for the bending radius of the cable. Cable easily moves on it without any scratch on it and cable puller feel less weight on it. Cable roller mainly two types according its using location.
    1. Straight Line Cable Rollers
    2. Corner Cable Rollers 
    3. Draw Off Rollers
Straigth Cable RollerCorner Cable Roller
The straight line cable rollers are used at straight part of the cable trench. Normally 3m to 4m apart it be used, also consider the cable weight and  diameter. Straight cable rollers protect the cable to touch the bottom and soil surface that may cause scratch on cable outer jacket. 

Corner Rollers are to be used within the cable trench where there is a bend in the  cable trench. Actually corner cable rollers are incorporated a vertical and horizontal cable roller to allow cable pulling safely without any damages. Actually corner roller protect cable from extra stress on cable outer jacket due trench bending.

Draw Off Roller is one kind of cable pulling roller which is used near the cable drum during cable pulled off from drum to trench. It is used to direct or guide the cable to the trench in straight line.

 Cable Drum Trailer- The cable drum trailers sense to transport the cable drum from one place to another in site, on the other hand cable trailer is also mean to stabilize the cable drum while the cable is being pulled through the cable trench or cable ducts. Cable drum trailer using to stabilize the drum during cable pulling is commonly used as Cable Jacks.

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  Cable Jointing Tools & Equipment

To prepare the cable to joint each other or for cable sealing end many especial tools and equipment are necessary to a cable jointer. It also varies from types of cable and types of jointing accessories. A very common tools list is to be used cable jointing and termination works.

List of Common Tools Used for Cable Jointing and Sealing End Termination
Sl. No. Name of Item Qty(pcs) Item Code Remarks
1 Al Sheath Cutter 1 T3201-005
2 Band Saw 1 J3041-017
3 Temperature Control Box 1 J1090-066
4 SRC & Slip-on Insert Tool 1 T1020-031 50 Ф -140Ф
5 Hydraulic Compression Pump 1 J3061-064 Small
6 Hydraulic Compression Tool 1 J3074-054 Small
7 Hydraulic Punching Tool 1 T3001-038
8 Electric De-humidifier 1 J1120-033
9 Vernier Calipers 1 M2064-062 Damage
10 Belt Sander 1 T1042-073
11 Humidity Meter 1 M2120-054
12 High Voltage Insulator Tester 1 M2032-028
13 Torque Wrench 1 M2014-014
14 Pressure Gauge 1 C1220-062
15 Rubber Sleeve Installation Machine (132KV) 1 J1132-009
16 Hydraulic Compression Pump 1 J3060-050 Big
17 Hydraulic Compression Head 1 J3072-055 Big
18 Hydraulic Compression Tool Set 1 T3092-046 Small
19 Impact (Big) 1
20 Impact (Small) 1
21 Red Box 1 25 & 26 missing
22 Jack saw 1 Damage
23 Hammer Drill 1
24 Heat Gun 1
25 Drier 1
26 Vacuum Cleaner 1
27 Lever Block
0.8 Ton 6
0.5 Ton 8
0.25 Ton 6
28 Hand Lamp 4
29 Soldering Iron 2
30 Heating Belt 15
31 Extension Cord 3
32 Heat Belt Power Cable  14
33 Thermometer 4
34 Oil Gate Valve 2
35 Ratchet Belt 16
36 Saw Cutter 1
37 Gas Torch 1
38 Cylinder (Big) 1
39 Cylinder(Small) 1
40 Burner 4
41 Aluminum Angle 9 1.5m
42 Nose Cone (132KV 500sq.mm) 1
43 Eye Bolt
M-16 4
M-12 6
M-10 4
44 300 Scale 3
45 600 Scale 1
46 Transformer 1
47 Blower 1
48 OFC Material Box 1
Consumable Item for Use During Cable Joint and Termination
Sl. No. Item Name Qty  Item Code Remarks
1 Wrap 30 Pcs
2 Aluminum Foil 30 Pcs
3 P.E Tube (1800 mm) 1 Role
4 P.E Tube (600 mm) 3 Role
5 Hand Gloves 20 Bundle
6 130 C tape 30 Pcs