Solution. Supplementary Bonding is the use of a slighter thinner (4mm) green and yellow copper cable to connect together all metal pipes (and possible circuits) in a particular area. Main bonding is 10mm, supplementary bonding is Supplementary bonding cable size: Effectively connected? The supplementary equipotential bonding (Table 1) must have a minimum cross section of 2.5 mm 2 Cu for a protected installation, and 4 mm 2 Cu for an unprotected Do you fully understand what supplementary bonding is ? Chapter 54 of the 18 th Edition covers earthing arrangements and protective conductors. Each multi-conductor cable with its individual EGC conductor. If you want your earth up to date then yes get it done, that answer from ark installations is not correct if you have a earth rod then that should be 10mm, and all earthing does not have to be An additional water heater at another location in the premises also has no bonding. The main equipotential bonding conductor need not be more than 25 mm2, so you can take the main equipotential bonding conductor from the MET to the first stanchion in 25 mm2. Top : Bottom. Bonding is a connection of metallic parts with a by Steve the gas Sat Mar 21, 2009 6:58 am. The minimum size supplementary bonding conductor size allowed is 2.5mm with mechanical protection with a circuit cpc size of upto 4mm2 OP D Deleted member 26818 Apr 15, Grounding and bonding of cable trays There are three wiring options for providing an EGC in a cable tray wiring system: 1. They should have a cross section less than An EGC conductor in or on the cable tray. There would be a safe path, if fault occurs at 10Hp motor side. Obtain the resistance per metre of 10mm 2 cable. Where connected to a rod, pipe, or plate electrode, 250.66 (A) permits the grounding electrode conductor or bonding conductor to be not larger than 6 AWG copper or 4 Protective bonding conductors Minimum cross-sectional areas for supplementary bonding SPE1 SPE2 SB 47. Does a metallic cable tray require earthing or bonding? One is via a table and on most supplies (especially in domestic & light commercial) will require that the bonding conductors are at least half the size of the main earthing conductor. The alternative method applies to TN-C-S supply earthing arrangements. This, in a nut shell, requires that the bonding conductor sizes are a minimum of 10mm 2. Table I1 of the On-Site Guide (OSG) and Table B1 of GN3 gives the resistance as 1.83 m/metre (0.00183 /m). What is an extraneous conductive part and do you bond it. Sometimes the term Zearth bonding is used and this complicates things further as the earthing and bonding are two separate connections. How to size earthing and CPC conductors the easy way. How do you ensure earthing? with tin or zinc plated connectors. In short the answer is 'depends' but the answer could be earthing, bonding or neither depending on the circumstances. Principles of Cable Sizing. If you want your earth up to date then yes get it done, that answer from ark installations is not correct if you have a earth rod then that should be 10mm, Supplementary Bonding is the use of a smaller, thinner (4mm) green and yellow copper cable to connect together all metal surfaces in a particular area. This area is typically the bathroom, or any other room containing a bath or shower. Not even an unconnected clamp. bonding Notes: 1. Should there also be main bonding run as well? I presume you are talking about the difference in the size difference of the cpc in the shower cable compared to that in the 1.00mm2 lighting circuit. Supplementary bonding is an entirely different thing that connects all pipework and electrical earths together in the bathroom. Supplementary bonding of pipes at combiler or in tank Regarding this, what size cable is used for earth bonding? Their positions are all within a 3m span. Also to know is, what size cable is used for earth bonding? What size should earth bonding be? Earth Bonding Cable Size Selection. 1. Protective conductors (including earth and bonding conductors) of 10mm cross-sectional area or less shall be of copper. 2. The distributor may require a minimum size of earth conductor at the origin of the supply of 16mm copper or greater for TN-S and TN-C-S supplies. 3. Looking at each of these in turn: If the tray is an exposed conductive part it requires earthing. A supplementary bond is not run back to the main earth 3. If you want your earth up to date then yes get it done, that answer from ark installations is not correct if you have a earth rod then that should be 10mm, and all earthing does not have to be I will probably use the lighting circuit as the shower cpc would need a heavier earth cable. Supplementary bonding is to reduce the Supplementary Bonding Conductor Sizes See Regulation 544.2.1 to 544.2.3: If mechanical protection is provided then its 2.5mm, all other instances 4mm minimum which is There is no cable. Similarly, is 6mm bonding adequate? Use multimeter 2. Bonding to services - gas and water services is 10mm2. Supplementary Bonding is the use of a slighter thinner (4mm) green and yellow copper cable to connect together all metal pipes (and possible circuits) in a particular area. Main earth at cut out ( PME or TNCS) is now 16mm2. Earthing and bonding - Power cables 1. To summarise this table, sizing is completed by reference to the size of the PEN (Protective Earth Neutral) conductor of the supply. For 25mm tails this results in a 16mm main earth. I see this a lot on sites where theyve got an armoured cable with an earthing ring/banjo connecting the armour to an extraneous conductive part. Where connected to a rod, pipe, or plate electrode, 250.66 (A) permits the grounding electrode conductor or bonding conductor to be not larger than 6 AWG copper or 4 AWG aluminum. MrJack96 over 2 years ago. The main reason for this is the ability of rod (s), This area is typically 10mm . Supplementary bonding is not to do with ADS; that would be earthing and it is not likely that a pipe will be an exposed-conductive-part. The main earth conductor needs to be sized according to the size of the phase conductor and in this case would be 35 mm2. PEN conductors of anything less than 35mm Minimum size of earth wire for light circuit is 1 mm square for copper and 1.5 mm square for aluminum. Supplementary bonding. Does the earth cable for water and gas need to be a separate cable to the supplementary bonding one? And also assume all should go back to the consumer unit? The ideal scenario might be to connect the supplementary bonding to the water mains bonding then run to pick up gas mains bonding and on to the consumer unit. Cables in walls of bath or shower rooms have to be protected by a 30mA RCD. steve CF, Oct 12, 2007 #4. Now main bonding to gas and water services must be connected within 600mm of stop tap and supply from gas meter. NEC Table 250.122 Minimum size equipment grounding conductors for grounding raceway and equipment For such installations, it is best to use an insulated conductor and to remove the insulation where bonding connections are made to the cable tray, raceways, equipment enclosures, etc. Bonding all 10mm but supply cable is 16mm T&E, so 6mm main earth. Supplementary equipotential bonding (between waste pipes, metallic service pipes and earth connections of bathroom equipment) is no longer required if, and only if, the main bonding between metal service pipes can be proved to be continuous. Bonding water and Gas pipes. This area is typically the bathroom, or any other room containing a bath or shower. My understanding is :-. Section C: 3. The copper pipe is fed from a blue plastic cold water supply pipe from the water board stop tap. The distribution system in this section is designed such a way that the size of each earth continuity conductor (from 10Hp motor to the connecting point E) is 6 SWG but, for 2Hp motors, the size of earth conductor is 14SWG. All conductors should be made of copper. A. Supplementary Bonding is carried out to the earth terminal of equipment within the bathroom with exposed-conductive part. Using regulation 543.1.3 and the calculation method, the size of the protective conductor chosen is typically smaller than through selection. The maximum length L of a 10mm 2 main protective bonding conductor can be found from: 0.05 . L = 0.00183 /m = 27.3 metres. Share this article. The most typical method chosen is selection, in accordance with table 54.7 and the size selected is based on the cross-sectional area of the line conductor. All earth bonding clamps are on the same 15mm copper cold water supply pipe. The Earthing conductor and main protective bonding conductor sizes (copper equivalent) for TN-S and TN-C-S supplies are determined as follows: Notes: 1. Protective conductors (including earth and bonding conductors) of 10mm cross-sectional area or less shall be of copper. The cable tray itself is used as the EGC in qualifying facilities. 09/01/2018.