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What is House Wiring?
What is wiring?
When wire, switch, holder etc. are installed according to the Indian Electricity rules in a circuit it is called wiring.
Type of wiring system:-
1. Tree system
2. looping system
3. connector system
4. distribution system
What is tree system wiring?
This is a one kind of process of the technique when we take a load from branch circuit are tapped from main line this technique is known as tree system wiring.
- The length of the wire required is less.
- It can be installed easily.
- It is suitable for high rise buildings.
- Fault location is difficult.
- This system has a high voltage drop.
- The whole line has to be switch off for finding the fault.
- Looking of the system is very poor
Use :-Tree system wiring are used for temporary process.
it is also used in workshops for giving the supply through bus bar.
Distribution System wiring:-
In this system the main supply is brought to first main switches from where it is distributed to different distribution boxes from where it is further distributed to different branch circuits .This system requires no joints, each circuit can be readily disconnected from the main without interfering with the other circuit. Nowadays this system is widely used.
- Appearance is good
- Fault location is very easy.
- The voltage available at the different load points will be the same.
- Renewal or extension of the circuit is easy
- As the need arises the defective circuit can be switched off.
- Replacement of fuse is easy.
In this system the length of the wire required for the wiring is more, so its initial cost is also more.
Looping Method System wiring:-
This method of wiring is jointless. Separate phase wires are taken for each circuit from the distribution box directly.
The neutral line remains common for all the circuits . If an extension is required, then it would be taken from the distribution box or from a ceiling rose, socket, switch etc., but it would not be taken by making a joint in the line.
- It looks beautiful
- It is joint less.
- It has a high insulation resistance.
- It requires more wire.
- It is expensive.
- It requires more space.
Connector Method System wiring:-
In this method connectors are used midway between the wiring. Connector serves as distribution junction for the phases well as for the neutral line. A connector is fitted over each joint.
- It requires less wire.
- It is inexpensive.
- It has a low voltage drop in the conducting wire.
- It can be installed promptly.
- The joints may remain loose.
- It does not look beautiful.
Electrical appliances connection systems:-
The electrical appliances can be connected with supply by the following two methods
- Lopping connection
In this system of connections all the joints are connected through cut-out three plate ceiling rose, connector etc.
- Less wire is required.
- Less voltage drop
- Low power consumption
- Less cost
In this system of connection are taken from ceiling rose etc. the distribution box is used to get looping for connection of supply .
- Good looking
- All the joints are inside the box.
- Less maintenance.
- More wire is used.
- It is difficult to locate fault except in Batten wiring.
B.I.S. Rules for wiring:
The following are the general rules which should be kept in mind before un installation of wiring.
- According to B.I.S. rule, the total lighting load in a sub-circuit should not exceed 1 Kilo watt (1000 w) or number of points between 8 to 10 points whichever is less. For estimating the lighting load, the values should be considered 60 w each for ceiling fan and socket 80 w each.
- The cable used in the wiring should be kept free from moisture, chemicals fumes and fire.
- All the metal covering should be earthed such as the cover of the main switches, earth point of the wall socket etc.
- Phase wire should be protected by a fuse.
- No fuse or switch is used in earth wire.
- The height of the board in an installation should be 5 feet from the ground level and should be fixed on ieft hand side of the entrance.
- The height of the fan and light points should be 9 feet and 8 feet respectively from the ground.
- Every sub-circuit must have a separate distribution board.
- Three phase supply should be indicated with Red, Yellow and Blue. And the neutral should be indicated with Black.
- The light and power circuits should be kept separately.
- The current rating of the main switch and distribution board should be calculated according to the load on the circuit.
- All 440 volts machines should be double earthed.
- Round blocks should be fixed with two screws.
- When the wiring has been completed, it should be tested with the megger before giving the supply.
- All the motors, switches and starters should be easily accessible to the operator.
What is Electric Wearing?
Electric Wearing is the process of install electrical equipment like wire , switch, holder etc. according to the electricity rules is known as wiring.
What is DC motor?
A Motor is a mechanism by which electrical energy is converted into mechanical energy. Both in principle and in design, a DC motor is the Reserve of a DC generator.
LOW VOLTAGE SWITCHGEAR TERMINOLOGY: –
Before understanding LV switchgear, one must know the terminologies related to the Electrical
Switchgear:- General term covering switching devices and their combination with associated control, measuring, protective and regulating equipment, also assemblies of such devices and equipment’s with associated interconnections, accessories, enclosures and supporting structures, intended in principle for use in connection with generation, transmission, distribution and conversion of electric energy
What is switchgear?
A device or a combination of devices, primarily intended for the purpose of making, carrying and
breaking electric currents in circuits under normal conditions as well as under abnormal (faulty) conditions.
General term covering switching devices and their combination with associated control, measuring, protective and regulating equipment, also assemblies of such devices and equipments with associated interconnections, accessories, enclosures and supporting structures, intended in principle for the control of electric energy consuming equipment
The LV Electrical Switchgear Terminologies are generally with respect to the following parameters:
- Behaviour under Normal & Overload Conditions
- Behaviour under Short Circuit Conditions
- Utilization categories
TERMINOLOGIES RELATED TO VOLTAGE
Rated Operational Voltage (Ue): The rated operational voltage of equipment is a value of voltage, combined with rated operational current, determines the application of the equipment and to which the relevant tests and the utilization categories are referred.
This is the voltage that would normally be available continuously across the terminals of different phases of the switchgear. Unless otherwise specified, this rating will be 415V for LV Switchgear. This implies that even while 415V @50Hz is present between the terminals, there will not be any flash-over (i.e.) the insulation between phases is sufficient to tolerate a potential difference of 415V continuously.
Rated Insulation Withstand Voltage (Ui):-
Then, one might ask, at what voltage the inter-phase insulation would fail, if it would not fail for 415V. There are two possibilities (viz.) transformer tap changers & the system fluctuation on the upper side. One can go by the permissible fluctuations in the supply voltage (+10%) vide IER 54 – and the worst probable tap ratios in transformers (+/-12.5%). Considering that the worst condition of the transformer taps in the maximum position and at the same time, the system voltage too fluctuates on the plus side, there could be a very high system voltage on the switchgear.
If the Switchgear is exactly rated for 415V, then under the above conditions, it would fail. So, another rating Called ‘Ui’ specified. Normally this would be 690V for LV Switchgear. Even under the worst condition as described above, the 415V system voltage would not go beyond 595V. So, swithgear rated for a Ui of 69OV would very well withstand the above condition.
Rated impulse Withstand Voltage (Uimp): –