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Earth Bonding Upgrades in Essex

electrical contractor in Essex and London.

delta T Electrical are able to carry out earth bonding upgrades in Essex and the surrounding areas.

Our team of fully qualified NICEIC registered Electricians, who are Part “P” certified work quickly and efficiently thereby minimizing the disruption to you and your premises.

All of our local electricians hold both City and Guilds 2381/2382 and 2391 electrical qualifications and are fully experienced in the inspection and testing of commercial, industrial and residential premises and can advise you of any earth bonding upgrades necessary to keep you within the current regulations.

There are two types of bonding, Main Bonding and Supplementary Bonding.

Most properties built before 1991 generally have the bonding wired in 6mm or 4mm cable this is no longer compliant with the BS 7671 – Requirements for Electrical Installations IET 17th Edition Wiring Regulations if you would like your earthing system checked or earthing system upgraded please call our help desk or use the contact form to book an appointment.

The nature of this work means that the electrician Essex based delta T Electrical sends to carry out these works will have to conduct a series of electrical tests in order to be able to issue an NICEIC certificate for all of the earth bonding upgrades to demonstrate compliance with the 17th Edition Regulations.
Main Bonding
What is Main Protective Bonding?
Main protective equipotential bonding connects the main earthing terminal with the following extraneous conductive-parts (Regulation 413.3.1.2):

(i) Water installation pipes

(ii) Gas installation pipes

(iii) Other installation pipes e.g. oil, compressed air-lines and ducting

(iv) Central heating and air conditioning systems

(v) Exposed metallic structural parts of the building

(vi) The lightning protection system where required in accordance with BS EN 62305


1) Incoming plastic gas and water services pipes do not require bonding

2) Where an installation serves more than one building the requirements shall be applied to each building

3) The above list is not exhaustive

Main Bonding is used to connect the Water, Gas and Oil services to the Earth Terminal in or adjacent to your Distribution board. Connections are made on the metal pipes near the point at which they enter your premises, i.e. The Main Bonding is normally connected within 600mm from your gas meter and water stop cock.

Main Bonding is there to protect you. A fault current will always try to find a path down to earth, literally to the ground. The current will always take the easiest path to ground; the idea of Main Bonding and Supplementary Bonding is to create an alternative path for the current to flow that is an easier path than along one of your heating pipes, along your arm, through your body, down your legs to the wet kitchen floor and to ground. By using a thick copper cable, you are creating a path that is more inviting to any fault currents and will divert any fault currents from your body or places where it should not go, as the current flows down to ground.

As long as the Water pipe, Gas pipe or Oil pipe, coming into your property are metallic, Main Bonding is compulsory in all circumstances even when the rest of the pipes in your house are plastic.

BS 7671 does not specify where main protective bonding conductors should be connected to central heating pipes or air conditioning systems etc. but it would seem sensible to make these connections so that in the event of any subsequent alterations the connections would remain in place. BS EN 62305 Protection against Lightning requires the connection to be made to the lightning conductor above the test clamp, so that when testing the lightning system earth it is disconnected from the electrical installation earth.

Main Bonding General Arrangement

Bonding picture

Supplementary Bonding

Regulation 411.3.2.6 requires the installation of supplementary bonding where the required disconnection time cannot be achieved. The supplementary bonding shall connect together all exposed and extraneous conductive parts in the area of the circuit(s) concerned.

Where this method is used, consideration needs to be given to the need to disconnect for thermal protection purposes using the adiabatic equation in Regulation 434.5.2.

Supplementary Bonding is used to connect together all metal pipes and possible circuits.

As a general guide all exposed conductive materials that can be touched or come into contact with people should be earthed in a commercial and industrial environment.

When should Earth Bonding be upgraded?

The current wiring regulations BS 7671 – Requirements for Electrical Installations IET 17th Edition Wiring Regulations require upgrading of the earth cabling to your gas and water pipes when changing a consumer unit, or when carrying out any works that are notifiable, these cannot legally be carried out without the correct bonding being in place.
This is sometimes a simple job but can mean a lot of work depending on the location of your consumer unit, water stop cock and gas meter. The BS7671/IET Wiring Regulations are set out to ensure safe & reliable electrical installations. delta T Electrical are able to carry out all earth bonding upgrades in Essex and the surrounding areas. And issue you with all the certified paperwork, to ensure you remain compliant.

Supplementary Bonding

Note: Regulation 415.2.2 states that where doubt exists regarding the effectiveness of supplementary equipotential bonding, it shall be confirmed that the resistance R between simultaneously accessible conductive parts and extraneous conductive parts fulfils the following condition:
R ≤ 50V  a for a.c. systems
By example, using a 30mA RCD (Required by 415.1.1)
R ≤ 50V  30mA = 1667 ohms

Where supplementary bonding is required, Regulation 701.415.2 requires that the protective conductor (cpc) of each circuit entering the room containing a bath or shower, be connected to the extraneous-conductive parts by local supplementary equipotential bonding conductors complying with Regulation group 544.2.

This is carried out to prevent the occurrence of voltages between any such parts being of such magnitude as could cause danger of electric shock. Ie current bonding is absent or inadequate.

Automatic Disconnection Of Supply

Before any additions or modifications can be carried out on an electrical installation, the Regulations require that certain safety features are present in the existing installation. The most fundamental of these are Automatic Disconnection of Supply (A.D.S.) and Equipotential Bonding.

You can rest assured that the electrician Essex based delta T Electrical sends to carry out the works will hold City & Guilds electrical qualifications and be fully competent to advise you of any works necessary to meet the 17th Edition Regulation and allow him to issue an NICEIC certificate for any works carried out on your premises.

ADS is a method of connecting most exposed metal work in a building and metal appliances to electrical Earth, assumed to have a potential of zero volts. This means that in the event of a fault - e.g. a Live wire touching a metal case, the earth will facilitate automatic disconnection of the mains supply. This should cause the circuit protective device to break, disconnecting the supply.

delta T Electrical are able to carry out testing and advise you what works will be necessary to make your earth bonding installation compliant and safe.

delta T Electrical are NICEIC registered domestic and commercial installers, Part “P” certified earth bonding upgrades in Essex and the surrounding areas are our speciality.

delta T Electrical are your local Electrical Contractor Essex is the base for our operations from which we can carry out a full range of electrical services in Essex and the outlying areas.

Please give the helpdesk a call or fill in our contact form to arrange an appointment.

Our Services

delta T can offer a wide range of mechanical and electrical services throughout Essex, London & Suffolk no matter what discipline you are looking for you can rest assured we are here to help, We are a fully accredited NICEIC domestic and commercial contractor experienced in all fields of electrical installation, service and maintenance. We offer the full range of air conditioning and ventilation including MVHR throughout Essex, London and Suffolk areas, If you have a project you would like us to help you with please send us an email via the contact page with a brief description of your needs and we will contact you to discuss how we can be of assistance to you !

We can offer business finance options and accept credit card payments from all major providers