Rules & Regulations to Earthing

Rules & Regulations to Earthing

Rules & Regulations to Earthing- The electrical rules that deal with earthing (i.e., which have to be taken into consideration at the time of earthing, or by keeping because of which earthing is done) are known as electricity rules relating to the earth. The following earthing rules have been devised;

Rule No. 54; Metal Casing or Metal Pipe

A metal casing or pipe through which electrical wires are run or which has been installed for the protection of electrical appliances is necessary to be earthed. Wherever metal pipes are used in different pieces, it is necessary to connect all these pieces properly together, so that an electric cohesion develops in them.

The following metal objects are not necessary to be earthed.

Metal pieces are mounted on walls, lamp holders, brackets, regulator switches, etc., however, it is necessary to earth the metal casings of hand lamps being used in factories.

Rule No. 57; Earthing of Electrical Machines

The casing of every generator, motor, transformer, converter, and corresponding regulating and controlling components must be connected to the earth from two separate places.

Rule No. 58; Earthing of Neutral Wire

Wherever a neutral is used in a distribution system, and there are more voltages than 125 volts between phase and neutral, then neutral should be earthed from separate places of the busbar under the following conditions;

(i). System should be earthed at one place on the generating station or sub-station, and in all other places, neutral insulation should be maintained with earth.

(ii). Water or gas pipes, which are not the property of the person undertaking earthing, should not be earthed, however, earthing can be done following an inspector or owner’s approval.

(iii). The earth connection for neutral will not be done separately besides testing, and immediately after the testing, it will be restored. The period, during which a connection has to be retained open, will have to be properly recorded.

(iv). The supply company can open an earth connection between one AM to 3 AM.

(v).In a situation of DC supply, the supply company will have to keep a proper record of the current passing through the ground (leakage current). If this current exceeds 1 / 1000 of the overall current during any moment, then efforts should be made to rectify it.

Rule No. 59; Earthing of Concentric Conductors

In a situation of application of concentric conductors, it is the responsibility of an owner to maintain the insulation of all conductors from start to end. When anybody generates electricity just for his own personal use, he can use it by uncovering the external conductor (i.e., without insulation), provided it has been earthed, and it can be dissociated from a switch, cut out circuit breaker.

I.E.E Regulation for Earthing

Whatever the method of earthing being adopted, every protective conductor (earth conductor) should be selected and mounted in such a way that it can fulfill the regulations’ requirements for the electrical appliances mounted on the installation, to work properly and securely. The following regulations have been advised by the Institute of Electrical Engineers (I.E.E) regarding earthing;

Regulation D-1; Protection Against Earth Current

All electrical appliances and conductors can be safeguarded against the danger of earth leakage current through any one of the following mentioned methods;

(i). Insulation overlapping on them should be durable and persistent, i.e., fully insulated from the manufacturing point of view.

(ii). Wherever necessary, double insulation should be applied for fitting electrical appliances or lighting.

(iii). All exposed metal parts must have properly been earthed according to the section’s needs.

(iv). Metal parts should have been separated in such a fashion that they do not touch live parts or earthing parts. Regulation D-1 does not apply to such equipment or conductors which are provided 110-volt D.C through rectifiers connected with the battery, generator, or three–phase transformer.

D-2 Regulation

An earthing terminal should be provided nearby the consumer’s terminals for every installation working on voltages exceeding the extra-low voltage. An earth continuity conductor should be provided and connected to the consumer’s earth terminal along with all circuits on such an installation.

D-3 Regulation

All metal works except current-carrying parts e.g., cable sheaths and armor, conduit, ducts, trunking, boxes, and catenary wires, should be connected to appropriate earth continuity conductors. This regulation doe not apply to isolated metal parts.

D-4 Regulation

All exposed parts of appliances should be connected to some proper earth continuity conductor. This regulation does not apply to the double insulated apparatus as mentioned in regulation D-1.

D-5 Regulation

Every earth terminal of the final sub-circuits socket-outlet should be connected to the earth continuity conductor. Wherever, an earth continuity conductor has been manufactured from a conduit, trunking, duct, cable’s metal sheet, or cable armor, then according to British standards, every socket outlet’s earth terminal should be connected to the selected conductor.

D-6 Regulation

An earth terminal should be provided at every lighting point, and it should be connected to the earth conductor of the final sub-circuit.

D-7 Regulation

The earth terminal touched with the final sub–circuit’s earth continuity conductor should be provided on every lighting switch position.

D-10 Regulation

The earthing terminal of a consumer should be connected to the public gates and water metal work (metal pipe) entering into a consumer’s premises.

D-12 Regulation

As far as possible, the earth terminals tied along with gas or water pipes should be connected at the entrance point (i.e., the nearest point) of these pipes.

D-13 Regulation

In the binding method mentioned under regulation D-10, the minimum size of copper-binding wire should not be less than 2.5 sq. mm. However, the appropriate size of the binding wire is 6 sq. mm.

D-14 Regulation

Exposed metalwork (external metal parts) of all electrical apparatus, which is difficult to be isolated from external permanent metalwork, must be earthed. The consistent metal work includes showers fitted in baths, outer metal pipes, radiators, sinks & tanks, metal frames for mobile equipment on which electrical appliances are installed, e.g., crane, lift, etc., and metalwork where easy access can be possible.

D-22 Regulation

The fuses and excess current circuit breakers installed for providing protection against earth leakage current should work in such a way that they turn a faulty circuit dead at a time when earth faulty current operating this safety equipment, exists and its quantity be as below;

(i). When the current rating of semi-enclosed fuses used for providing protection to circuits, becomes three times or in a situation of a cartridge fuse when the fusing factor exceeds 1.5.

(ii). When the rating current of any cartridge fuse, having a fusing factor less than 1.5, becomes 2.4 times.

(iii). When the tripping current of a circuit breaker, providing safety to the circuit, exceeds 1.5 times.

D-23 Regulation 

If safety appliances meeting the requirements mentioned in regulation D-22 are not available, then proper earth leakage circuit breakers should be installed for earth leakage protection.

D-28 Regulation

Every conductor being used as an earth continuity conductor must essentially meet the following requirements;

(i). If the conductor has been prepared from a sheathed solid cable instead of a flexible cable or wire, it should be according to the corresponding British standard (i.e., its size should be according to the British standards)

(ii). If the conductor is in a flexible or elastic cord or cable form, the size of its cross-section must not be less than the largest current-carrying conductor having been used in the circuit.

(iii). Every cable sheath or cable armoring which has been used as an earth continuity conductor, should fulfill corresponding requirements as per British standards.

(iv). The joints of every earth continuity conductor manufactured partially or wholly from any metal conduit, duct, or trunking, should mechanically be strong. They must have electrical coordination and wherever necessary, they must be protected against rust. This has been mentioned in part V of regulation D-29.

(v). The cross–section area of conductors and copper conductors as mentioned above in parts (i) and (ii), should not be less than the size given in the table D-2 M (this table has been described in the coming pages) and in case of unenclosed or open conductor, its minimum size should be 1.5 sq. mm. If some other type of material is used as an earth continuity conductor instead of copper, then its resistance should not be above the resistance of the mentioned copper conductor.

D-29 Regulation

The following appropriate requirements should be met during the installation of every earth continuity conductor;

(i). Besides a copper strip, the cross-section area of every earth continuity conductor which has been described in section (v) of regulation D-28, should be up to 6 sq. mm, and the whole conductor should be secured through a proper type of insulation.

(ii). The sheaths of the earth continuity conductors as mentioned in regulation D-28 (i), should be removed only at the time of making joints and doing terminations. After putting joints, the conductor should be protected through an insulation sleeve. Moreover, the cross-section area of this conductor along with the sleeve should be up to 6 mm.

(iii). As far as possible, exposed or bare earth continuity conductors as mentioned under regulation D-28 part (iii), (iv), and (v) must be protected against mechanical shocks and rust (particularly on termination points).

(iv). All joints of earth continuity conductors should be mechanically strong. They must have electrical continuity, and be protected against rust wherever required.

(v). Firm and strong connections should be done on cable sheaths or armoring and pipes through soldered joints or clamps. Every clamp should be mounted in such a way that it provides an enduring and lasting connection without inflicting any kind of damage on the corresponding cable or pipe.

D-30 Regulation

The different parts of gas and water pipes or metalwork should never be used as earth continuity conductors, however wherever required, they can be joined or connected with the earth continuity conductor.

D- 31 Regulation

The cross–section area of every copper conductor, which has to be used as an earthing lead, must never be less than the size given in table D-2 M. However, conductor size should not exceed 2.5 sq. mm for establishing a connection with the electrodes of earth leakage circuit breaker. The maximum size of a copper conductor tends to be 70 sq. mm. A size greater than this is never used except for the transformer’s neutral earthing, or earthing of the boiler electrode. According to this regulation, the corresponding conductor being installed on a consumer’s switch gear’s input side must be the thickest conductor of the circuit. In a situation of using a conductor made from some other material instead of copper, its resistance must not exceed the resistance of the corresponding copper conductor. For establishing a final connection with the earth electrodes, copper-clad aluminum conductors must never be used at all.

D-33 Regulation

Immediate access to every connection on an earthing electrode of an earth lead, or connection established through other sources of earthing, should be possible, and these connections done through soldered joints or clamps, must be solid. Above every connection, a label may permanently be fixed at a height of 4.75 mm, which should clearly be inscribed with the words;

“Safety Electrical Earth – Do Not remove”

D-35 Regulation

The metal works of public gas services and water services should not be used as earth electrodes of installations.

Table D-2 M

Minimum size of copper earthing, leads, copper bounding leads and copper earth continuity conductors not forming part of the same cable as the associated circuit conductors (see regulations D-13,14, 29, and D-31)

Nominal Cross – Sectional Area of Largest Associated Copper Circuit – Conductor 1Nominal Cross–Sectional Area of Earthing Lead 2Nominal Cross–Sectional Area of Earth Continuity Conductor 3Nominal Cross–Sectional Area of Bounding Lead 4

Next Topic: Earthing System for Industrial Installations

Previous Topic: : Steps of Calculating Cable and Fuse Size for Motor Circuit

For electronics and programming-related projects visit my YouTube channel.

My YouTube channel Link

Engr Fahad

My name is Shahzada Fahad and I am an Electrical Engineer. I have been doing Job in UAE as a site engineer in an Electrical Construction Company. Currently, I am running my own YouTube channel "Electronic Clinic", and managing this Website. My Hobbies are * Watching Movies * Music * Martial Arts * Photography * Travelling * Make Sketches and so on...

Leave a Reply

Your email address will not be published. Required fields are marked *

Back to top button