What is the function of a protective conductor?
Protective Conductors actually connect conductive parts of metal casings in electrical appliances, conductive parts of buildings and constructions etc. to good earthing electrodes. The function of Protective Conductors to reduce the magnitude of voltages during fault conditions. How to calculate CPC size or Circuit Protective Conductor Size?
What is a Circuit Protective Conductor (CPC)?
The circuit protective conductor of every ring final circuit (other thanthat formed by the metal covering or enclosure of a cable) should berun in the form of a ring having both ends connected to the earthingterminal at the origin of the circuit. CPC actually parts of earthing exposed conductive parts. Types of exposed conductive parts:
What is a PE Protective Conductor?
Protective conductor (identification: PE): conductor provided for purposes of electrical safety (source IEC 60050-195:2021 [1]). In the United States of America, instead of the more correct term “protective conductor” they mostly use the terms “equipment grounding conductor” and “grounding electrode conductor”.
Where do protective conductors start?
In TT systems (Figures 31F1 and 31L) and AC and DC IT systems (Figure 31M), protective conductors “start” from the grounding devices of low-voltage electrical installations. 1) The system may be connected to earth via a sufficiently high impedance.
What is a protective conductor?
Why are protective conductors required?
What is equipotential bonding?
What color are bare conductors?
What color is used to identify protective conductors?
Where do protective conductors start in TN-S?
What color is PE?
See 2 more
What color is the protective conductor?
green/yellowgreen/yellow is always and exclusively used to identify the protective conductor.
Is neutral a protective conductor?
In TN-C systems, the neutral conductor serves also as protective conductor and therefore it cannot be disconnected. Besides, in case of disconnection of the neutral conductor, during an earth fault the exposed-conductive-parts would take the rated voltage to earth of the system.
What is the use of the circuit protective conductor in electrical installation?
The circuit protective conductor (CPC) is used to provide protection from electric shock and to allow sufficient current to flow so the protective devices can trip.
What is the purpose of protective bonding conductors?
A supplementary protective bonding conductor is used to connect simultaneously accessible exposed conductive parts and accessible extraneous-conductive-parts to prevent a hazardous potential difference from occurring between them.
Can I tie the neutral and ground together?
No, the neutral and ground should never be wired together. This is wrong, and potentially dangerous. When you plug in something in the outlet, the neutral will be live, as it closes the circuit. If the ground is wired to the neutral, the ground of the applicance will also be live.
Can I use ground as neutral?
If wired properly, we can use neutral as ground wire. We cannot use ground as neutral as it doesn't provide the normal return path for the current.
What are the 3 types of protective devices?
Electrical Protective Device – Types of Protective DeviceFuse Wire or Fuse.MCB – Miniature circuit breaker.ELCB – Earth Leakage Circuit Breaker.ELCB & MCB.Earthing or Grounding.
What is continuity of protective conductors?
Continuity of circuit protective conductors (CPC) The purpose of this test is to verify that the CPC forms a continuous path around the circuit under test. The test is carried out (using either or both methods shown) as follows: Test Method 1: a) Temporarily link the line conductor to the CPC in the Consumer Unit.
What is a PME in electrical terms?
The 'PME' in PME supply stands for protective multiple earthing. It means that the neutral conductor is deliberately connected to earth at a number of points on the supply network. If you think of a simple network this would consist of a supply transformer, a radial distribution main and service lines to each customer.
How do you protect a neutral wire?
If the neutral conductor is correctly sized (including harmonics), no specific protection of the neutral conductor is required because it is protected by the phase protection. However, in practice, if the c.s.a. of the neutral conductor is lower than the phase c.s.a, a neutral overload protection must be installed.
Why neutral isolation is required?
This is necessary because if you do not have neutral isolation and the neutrals of both the sources are linked, then when only one source is feeding and the other source is OFF, during an earthfault, the potential of the OFF Source's Neutral with respect to earth will increase, which might harm any maintenance ...
What is a neutral circuit breaker?
The plug-on-neutral breaker is a type of breaker you can connect directly to your neutral bar, thus negating the need for a pigtail connection. It's almost the same as typical AFCI and GFCI breakers but isn't compatible with most standard breaker panels.
What is neutral failure?
Neutral failure is a serious condition. A break in the neutral conductor will simply result in a loss of the energy supply which leads to an Irrespective of load balance. Reasons for Neutral Failue.
What is the purpose of a separate circuit protectiveconductor?
For every length of flexible conduit, a separate circuit protectiveconductor of adequate size should be provided to ensure the earthcontinuity of the installation between the two ends of the flexibleconduit.
What conductor should be used for busbar trunking?
Adjacent sections of a busbar trunking used as a CPC should beconnected by a protective conductor of adequate size e.g. coppertape or link to ensure the earth continuity between the two sections.This requirement may be waived if it is certified by the manufacturerof the busbar trunking that the earth continuity between theadjacent sections of the busbar trunking is ensured by using theconnection accessories provided by the manufacturer.
What is a CPC?
The circuit protective conductor (increasingly called the CPC) is a system of conductors joining together all exposed conductive parts and connecting them to the main earthing terminal. Strictly speaking, the term includes the earthing conductor as well as the equipotential bonding conductors.
What conductor should be run in the form of a ring having both ends connected to the earthingterminal?
The circuit protective conductor of every ring final circuit (other thanthat formed by the metal covering or enclosure of a cable) should berun in the form of a ring having both ends connected to the earthingterminal at the origin of the circuit.
What is a bus bar?
What is Bus-bar? Bus-bar is the common header where one or multiple sources poor the power also one or more sources can take power simul...
Do you need a separate conductor for every socket outlet?
For every socket outlet, a separate circuit protective conductor ofadequate size should be provided connecting the earthing terminalof the socket outlet and the earthing terminal inside the enclosureaccommodating the socket outlet if the CPC is formed by theenclosure.
Where are protective conductors used for a single circuit?
Where two protective conductors are used for a single circuit, Regulation 543.7.1.205 requires the conductors to be terminated separately at each accessory and at the distribution board. This will often mean that the cpcs are required to share the same terminals as with other separate circuits, as shown in Fig 2. To avoid confusion a durable and secure warning notice and/or sign shall be provided indicating those circuits having a high protective conductor currents; this shall be positioned at the distribution board and clearly visible to any person modifying or extending the circuit.
How many mA is a protective conductor?
Consequently, where it is known or reasonably expected that the total protective conductor current in normal service will exceed 10 mA, the circuit shall be provided with a high integrity protective conductor. One way to achieve this for a radial circuit is to install an additional protective conductor from the final socket outlet directly back to the distribution board as shown in Fig 2.
What is the maximum conductor current required for a high integrity protective connection?
In an installation where a final or distribution circuit is expected to supply one or more items of equipment and where the protective conductor current is likely to exceed 10 mA a high integrity protective connection shall be provided by one of the following methods stated in Regulation 543.7.1.203:
How many earthing terminals are required for a CPC?
For the purpose of maintaining the integrity of the cpc, all accessories such as socket-outlets and connection units that are designed for high protective conductor currents must have available two separate earthing terminals to accommodate the individual connections (Regulation 543.7.1.204).
How many conductors are required for Section 543?
two individual protective conductors, each complying with the requirements of Section 543. Additionally the protective conductors may be of different types for example, the armouring of a SWA cable combined with an integral cpc.
What is the CSA of a single protective conductor?
a single protective conductor having a csa of not less than 10 mm2, comply ing with the requirements of Regulation 543.2 and 543.3,
Do all accessories need to be suitably selected for circuits with high protective conductor currents?
All accessories shall be suitably selected for circuits with high protective conductor currents and are required to have dual connections for providing a reliable connection to earth.
What is a protective conductor?
What is Circuit Protective Conductor? The conductor used in an electrical circuit to join together all exposed conductive parts and the main earthing terminal is known as Circuit Protective Conductor in short CPC. It actually includes the earthing conductor as well as the equipotential bonding conductors.
Why do use CPC - Circuit Protective Conductor?
CPC or Circuit Protective Conductors are meant for protection against high contact voltages by leaking fault currents! Protective Conductors actually connect conductive parts of metal casings in electrical appliances, conductive parts of buildings and constructions etc. to good earthing electrodes.
How to calculate CPC size or Circuit Protective Conductor Size?
In order to prevent overheating of the protective conductor during a fault, the cross-sectional area of a protective conductor (s) shall be not less than that determined by the adiabatic formula as follows:
What is an electrical circuit?
Electrical circuits are used protective devices like fuses, circuit breakers, or RCD to protect the circuit during a fault. While circuit fault event occurs sufficient current will flow around the earth fault loop to operate the of the fault protective devices and disconnect the fault. earthing conductors.
What is protective conductor?
As you already know, protective conductors are the main part of every earthing protection system, but the complexity of the system will increase with the requirements of information technology, voltage surge protection, local area networks, etc. with the risk of muddling the terminology somewhat.
Where to connect conductive parts?
Connect the conductive parts near the main LV distribution board to the protective conductor terminals.
What is the cross section of an earthing conductor?
2. Earthing conductor. Conductor providing the link with the earth electrode. It is generally not insulated, and has a minimum crosssection of 25 mm2 (copper) or 50 mm2 (galvanised steel).
What is an earth electrode?
Definitions. 1. Earth electrode. Set of conductive elements in contact with the earth . The earth connection is established according to local conditions (type of ground) and the required resistance value (Figure 1). Figure 2 – Earth electrode and earthing conductor. 2. Earthing conductor.
What is surge protector earthing?
Earthing of voltage surge protectors. This is designed to discharge the fault currents resulting from the elimination of overvoltages. These conductors must be as short as possible and only used for this purpose. The minimum cross-section is chosen according the manufacturers’ instructions: generally 4 to 16 mm2.
What happens when a fuse is not fuse protected?
When the device is not fuse-protected the fuses, or miniature circuit breakers, mounted on the distribution panel after the Watt-hour meter will operate.
Can conductive equipment be connected to a protective conductor?
The exposed conductive parts of this equipment must not be connected to a protective conductor.
What is a protective conductor?
Protective conductor (identification: PE): conductor provided for purposes of electrical safety (source IEC 60050-195:2021 [1]). In the United States of America, instead of the more correct term “protective conductor” they mostly use the terms “equipment grounding conductor” and “grounding electrode conductor”. It is not a current-carrying conductor and should never be energized under normal conditions.
Why are protective conductors required?
Since protective conductors are used as part of measures to protect against electric shock, special requirements are imposed on their characteristics, performance and technical condition by regulatory and legal documents.
What is equipotential bonding?
The protective equipotential bonding conductors in buildings are used to electrically connect external conductive parts to each other and to connect them to the earthing devices of the electrical installations of buildings. When carrying out additional equipotential bonding, protective equipotential bonding conductors connect exposed conductive parts of class I electrical equipment with external conductive parts in rooms of the building which are characterized by increased danger, e.g. have conductive floors.
What color are bare conductors?
If bare conductors used as protective conductors are provided with colouring they shall be coloured GREEN-AND YELLOW, either throughout the whole length of each conductor or in each compartment or unit or at each accessible position. If adhesive tape is used, only bi-coloured GREEN-AND-YELLOW tape shall be applied.
What color is used to identify protective conductors?
GREEN-AND-YELLOW is the only colour combination recognized for identifying the protective conductor.
Where do protective conductors start in TN-S?
In TN-S AC and DC systems, such as shown in Figures 31A1 and 31H, respectively, the protective conductors “start” from the earthed live parts of the power supplies.
What color is PE?
or the bi-colour combination GREEN-AND-YELLOW or the alphanumeric notation PE.
Application
- On the application of protective conductors, most capaciously, in my opinion, wrote Kharechko Y.V. in his book : « Protective conductors are used in low-voltage electrical systems both AC and DC, as well as in electrical installations of buildings that are part of these systems. » The followi…
Requirements
- Since protective conductors are used as part of measures to protect against electric shock, special requirements are imposed on their characteristics, performance and technical condition by regulatory and legal documents. About the basic requirements for protective conductors writes Kharechko Y.V. in his book : « One of the main requirements for protective conductors is to ensu…
Color and Alphanumeric Identification
- The following requirements are in accordance with . The protective conductor shall be identified by the bi-colour combination GREEN-AND-YELLOW. GREEN-AND-YELLOW is the only colour combination recognized for identifying the protective conductor. The colour combination GREEN-AND-YELLOW shall be such that, on any 1 5 mm length of the conductor where colour coding is …
Cross-Section of The Protective Conductor
- Cross-section of the protective conductor is selected according to Table 54.2 : Or calculate in accordance with clause 543.1.2 of . The cross-sectional areas of protective conductors shall be not less than the value determined either: 1. in accordance with IEC 60949; or 2. by the following formula applicable only for disconnection times not exceeding 5 s: where 1. S – is the cross-sec…
References
- IEC 60050-195:2021
- IEC 60364-1
- Kharechko Y.V. Concise Terminological Dictionary of Low Voltage Electrical Installations. Part 1 // Appendix to the journal “Library of the safety engineer. – 2011. – № 3. – 160 c. Personal English...
- IEC 60050-195:2021
- IEC 60364-1
- Kharechko Y.V. Concise Terminological Dictionary of Low Voltage Electrical Installations. Part 1 // Appendix to the journal “Library of the safety engineer. – 2011. – № 3. – 160 c. Personal English...
- IEC 60364-5-54-2011
