# \#switchgear **URL:** https://forumautomation.com/tag/switchgear/93.md [Latest](https://forumautomation.com/latest.md) · [Categories](https://forumautomation.com/categories.md) · [Tags](https://forumautomation.com/tags.md) --- ## [Calculate the wire size, MCB (Miniature Circuit Breaker) and ELCB (Earth Leakage Circuit Breaker) for a 20kW load](https://forumautomation.com/t/calculate-the-wire-size-mcb-miniature-circuit-breaker-and-elcb-earth-leakage-circuit-breaker-for-a-20kw-load/13863)
**Author:** [@Rabert](https://forumautomation.com/u/Rabert)\ **Replies:** 0\ **Last updated:** [January 30, 2026, 6:50pm UTC](https://forumautomation.com/t/calculate-the-wire-size-mcb-miniature-circuit-breaker-and-elcb-earth-leakage-circuit-breaker-for-a-20kw-load/13863 "2026-01-30T18:50:40Z")
Wire Size Calculation Step-1: Calculate Current Single phase: I = P / (V x PF) = 20000 / (230 x 0.8) ≈ 109A Three phase: I = P / (√3 x V x PF) = 20000 / (1.732 x 400 x 0.8) ≈ 36A Step-2: Apply Derating Factors Ambient … --- ## [Difference between MCB and MCCB](https://forumautomation.com/t/difference-between-mcb-and-mccb/853)
**Author:** [@automate](https://forumautomation.com/u/automate)\ **Replies:** 2\ **Last updated:** [July 11, 2026, 3:02am UTC](https://forumautomation.com/t/difference-between-mcb-and-mccb/853 "2026-07-11T03:02:22Z")
MCB - Miniature Circuit Breaker MCB is miniature circuit breaker which is thermal operated and use for short circuit protection in small current rating circuit. Normally it is used where normal current is less than 100… --- ## [PCC Panel (Power Control Center) Vs. MCC Panel (Motor Control Center)](https://forumautomation.com/t/pcc-panel-power-control-center-vs-mcc-panel-motor-control-center/14435)
**Author:** [@TSRS](https://forumautomation.com/u/TSRS)\ **Replies:** 0\ **Last updated:** [September 22, 2026, 2:21am UTC](https://forumautomation.com/t/pcc-panel-power-control-center-vs-mcc-panel-motor-control-center/14435 "2026-09-22T02:21:05Z")
PCC Panel (Power Control Center) The heart of main power distribution in any plant or facility. Function: Receives incoming main supply directly from the transformer or DG set and distributes high power through feeders … --- ## [SEMICONDUCTORS AND ITS USES](https://forumautomation.com/t/semiconductors-and-its-uses/6232)
**Author:** [@ashlin](https://forumautomation.com/u/ashlin)\ **Replies:** 0\ **Last updated:** [April 10, 2019, 5:45pm UTC](https://forumautomation.com/t/semiconductors-and-its-uses/6232 "2019-04-10T17:45:23Z")
SEMICONDUCTORS AND ITS USES The electrical conductivity of a semiconductor is between that of a conductor and an insulator the foundation of modern electronics are created by the help of a semiconducto… --- ## [Basics of Motor starters](https://forumautomation.com/t/basics-of-motor-starters/2780)
**Author:** [@sivaranjith](https://forumautomation.com/u/sivaranjith)\ **Replies:** 0\ **Last updated:** [December 6, 2017, 8:44pm UTC](https://forumautomation.com/t/basics-of-motor-starters/2780 "2017-12-06T20:44:02Z")
A motor starter is designed to provide power to motors. The motor starter is made up of a contactor with an overload relay attached physically and electrically to it . The function of the overload relay can be summarized… --- ## [Why are VCBs preferred for HT/MV Panels and ACBs preferred for LT Panels?](https://forumautomation.com/t/why-are-vcbs-preferred-for-ht-mv-panels-and-acbs-preferred-for-lt-panels/14380)
**Author:** [@Rabert](https://forumautomation.com/u/Rabert)\ **Replies:** 0\ **Last updated:** [September 11, 2026, 7:33am UTC](https://forumautomation.com/t/why-are-vcbs-preferred-for-ht-mv-panels-and-acbs-preferred-for-lt-panels/14380 "2026-09-11T07:33:15Z")
VCB in HT/MV Panels A Vacuum Circuit Breaker (VCB) is commonly used in HT/MV panels because it is designed for medium-voltage systems and provides reliable arc interruption. When the contacts separate during a fault, the… --- ## [What is MCCB? Explain the advantages of MCCB](https://forumautomation.com/t/what-is-mccb-explain-the-advantages-of-mccb/10169)
**Author:** [@Ajmal\_ismail](https://forumautomation.com/u/Ajmal_ismail)\ **Replies:** 0\ **Last updated:** [January 31, 2022, 7:31am UTC](https://forumautomation.com/t/what-is-mccb-explain-the-advantages-of-mccb/10169 "2022-01-31T07:31:26Z")
What is MCCB? MCCB stands for Moulded Case Circuit Breaker. It is a switching device that is designed to protect electrical devices from overload and short circuits. Fault sensing arrangements are installed inside MCCBs… --- ## [What is the purpose of anti-pumping in a circuit breaker?](https://forumautomation.com/t/what-is-the-purpose-of-anti-pumping-in-a-circuit-breaker/11223)
**Author:** [@Rabert](https://forumautomation.com/u/Rabert)\ **Replies:** 0\ **Last updated:** [June 9, 2023, 1:50pm UTC](https://forumautomation.com/t/what-is-the-purpose-of-anti-pumping-in-a-circuit-breaker/11223 "2023-06-09T13:50:44Z")
The purpose of the anti-pumping mechanism used in electrical circuit breakers is to prevent numerous shutting and opening actions of the circuit breaker contacts from occurring in rapid succession. It is a protection el… --- ## [Difference between High Tension and Low Tension Panels](https://forumautomation.com/t/difference-between-high-tension-and-low-tension-panels/14345)
**Author:** [@Rabert](https://forumautomation.com/u/Rabert)\ **Replies:** 0\ **Last updated:** [September 2, 2026, 12:25pm UTC](https://forumautomation.com/t/difference-between-high-tension-and-low-tension-panels/14345 "2026-09-02T12:25:25Z")
Difference between High Tension and Low Tension Panels What is an HT Panel? An HT Panel (High Tension Panel) is designed to operate at voltages above 1 kV, typically 3.3 kV, 6.6 kV, 11 kV, 22 kV, or 33 kV. It receives p… --- ## [Explain about different type of Earthing system](https://forumautomation.com/t/explain-about-different-type-of-earthing-system/166)
**Author:** [@denizen](https://forumautomation.com/u/denizen)\ **Replies:** 2\ **Last updated:** [August 31, 2026, 4:08pm UTC](https://forumautomation.com/t/explain-about-different-type-of-earthing-system/166 "2026-08-31T16:08:30Z")
different type of earthing system --- ## [Star-Delta Connection: Understanding Three-Phase Motor Starting](https://forumautomation.com/t/star-delta-connection-understanding-three-phase-motor-starting/14336)
**Author:** [@Rabert](https://forumautomation.com/u/Rabert)\ **Replies:** 0\ **Last updated:** [August 21, 2026, 2:38pm UTC](https://forumautomation.com/t/star-delta-connection-understanding-three-phase-motor-starting/14336 "2026-08-21T14:38:08Z")
A Star-Delta starter is used with suitable three-phase induction motors to reduce the starting current by initially connecting the motor windings in Star and then changing to Delta (A) for normal operation. The basic se… --- ## [What is the difference between 4 pole MCB and Triple pole and neutral?](https://forumautomation.com/t/what-is-the-difference-between-4-pole-mcb-and-triple-pole-and-neutral/10119)
**Author:** [@instrumentationtechi](https://forumautomation.com/u/instrumentationtechi)\ **Replies:** 4\ **Last updated:** [August 3, 2026, 7:59am UTC](https://forumautomation.com/t/what-is-the-difference-between-4-pole-mcb-and-triple-pole-and-neutral/10119 "2026-08-03T07:59:04Z")
Explain how the 4 pole MCB is different from Triple pole and neutral? Reference Image Provided by the Respondent --- ## [Why are START and STOP Push Buttons used in Motor Control Circuits?](https://forumautomation.com/t/why-are-start-and-stop-push-buttons-used-in-motor-control-circuits/14280)
**Author:** [@Rabert](https://forumautomation.com/u/Rabert)\ **Replies:** 0\ **Last updated:** [July 29, 2026, 3:11pm UTC](https://forumautomation.com/t/why-are-start-and-stop-push-buttons-used-in-motor-control-circuits/14280 "2026-07-29T15:11:48Z")
START and STOP push buttons are the most common control devices used in industrial motor control circuits. They allow operators to safely start and stop electrical equipment such as motors, pumps, conveyors, and industri… --- ## [What is Contactor? How a Contactor works?](https://forumautomation.com/t/what-is-contactor-how-a-contactor-works/5118)
**Author:** [@sivaranjith](https://forumautomation.com/u/sivaranjith)\ **Replies:** 0\ **Last updated:** [November 5, 2018, 1:49pm UTC](https://forumautomation.com/t/what-is-contactor-how-a-contactor-works/5118 "2018-11-05T13:49:31Z")
Definition of contactor: It is a cutting and control device generally driven by means of an electromagnet, designed to perform a large number of manoeuvres, in circuits with currents and powers that can reach relativel… --- ## [How does AFR series arc flash relay work?](https://forumautomation.com/t/how-does-afr-series-arc-flash-relay-work/11369)
**Author:** [@cqbluejay](https://forumautomation.com/u/cqbluejay)\ **Replies:** 0\ **Last updated:** [August 4, 2023, 8:18am UTC](https://forumautomation.com/t/how-does-afr-series-arc-flash-relay-work/11369 "2023-08-04T08:18:42Z")
Accidents of severely burning switchgear caused by arc short-circuit faults of switchgear are increasing, and accidents of main transformers being damaged by external short-circuit current impacts are also increasing yea… --- ## [Types of Relays and their symbols](https://forumautomation.com/t/types-of-relays-and-their-symbols/10033)
**Author:** [@Ajmal\_ismail](https://forumautomation.com/u/Ajmal_ismail)\ **Replies:** 0\ **Last updated:** [December 3, 2021, 5:45am UTC](https://forumautomation.com/t/types-of-relays-and-their-symbols/10033 "2021-12-03T05:45:18Z")
What is Relay? A relay is a kind of switch that is electrically driven. It receives a signal from the source to open and close the contact. Relays built into electrical appliances transmit electrical signals to other eq… --- ## [How does a Miniature Relay Holding Circuit Work?](https://forumautomation.com/t/how-does-a-miniature-relay-holding-circuit-work/14237)
**Author:** [@NicholasDeo](https://forumautomation.com/u/NicholasDeo)\ **Replies:** 1\ **Last updated:** [July 9, 2026, 4:11am UTC](https://forumautomation.com/t/how-does-a-miniature-relay-holding-circuit-work/14237 "2026-07-09T04:11:31Z")
How does a Miniature Relay Holding Circuit work? Reference Image Provided by the Respondent --- ## [Is it ok to connect a contactor before the MPCB?](https://forumautomation.com/t/is-it-ok-to-connect-a-contactor-before-the-mpcb/9123)
**Author:** [@instrumentationtechi](https://forumautomation.com/u/instrumentationtechi)\ **Replies:** 3\ **Last updated:** [July 3, 2026, 10:13am UTC](https://forumautomation.com/t/is-it-ok-to-connect-a-contactor-before-the-mpcb/9123 "2026-07-03T10:13:38Z")
I have a contactor, controlled by a PLC, and a motor protection circuit breaker. Does it matter which comes first and if so: why? I don’t think it matters because the contactor’s job is to latch and the MPCB secures the … --- ## [Why Emergency Stop push button use two Normally Closed (NC) contacts in a safety relay circuit?](https://forumautomation.com/t/why-emergency-stop-push-button-use-two-normally-closed-nc-contacts-in-a-safety-relay-circuit/13483)
**Author:** [@Rabert](https://forumautomation.com/u/Rabert)\ **Replies:** 0\ **Last updated:** [August 25, 2025, 4:29pm UTC](https://forumautomation.com/t/why-emergency-stop-push-button-use-two-normally-closed-nc-contacts-in-a-safety-relay-circuit/13483 "2025-08-25T16:29:47Z")
In a safety relay circuit, Emergency Stop (E-Stop) push button utilizes two normally closed (NC) contacts. Emergency Stop push buttons utilize two NC contacts to enable dual-channel redundancy & fault monitoring, ensuri… --- ## [How to select Circuit Breaker Sizes for SMDB?](https://forumautomation.com/t/how-to-select-circuit-breaker-sizes-for-smdb/14106)
**Author:** [@Rabert](https://forumautomation.com/u/Rabert)\ **Replies:** 0\ **Last updated:** [May 19, 2026, 8:08am UTC](https://forumautomation.com/t/how-to-select-circuit-breaker-sizes-for-smdb/14106 "2026-05-19T08:08:41Z")
How to select Circuit Breaker Sizes for SMDB? Many engineers still oversize (or) undersize breakers leading to: Nuisance tripping Poor protection Unsafe systems Here is a simple and practical method to select… --- ## [Switchgear and their Types](https://forumautomation.com/t/switchgear-and-their-types/14075)
**Author:** [@Rabert](https://forumautomation.com/u/Rabert)\ **Replies:** 0\ **Last updated:** [May 6, 2026, 6:18pm UTC](https://forumautomation.com/t/switchgear-and-their-types/14075 "2026-05-06T18:18:51Z")
Switchgear Switchgear controls, protects, and isolates electrical equipment. It ensures safe operation by interrupting faults and maintaining system stability. Importance of Protection in Power Systems Protection system… --- ## [Automatic Transfer Switch (ATS) Sequence of Operation](https://forumautomation.com/t/automatic-transfer-switch-ats-sequence-of-operation/12431)
**Author:** [@Rabert](https://forumautomation.com/u/Rabert)\ **Replies:** 0\ **Last updated:** [August 12, 2024, 1:10pm UTC](https://forumautomation.com/t/automatic-transfer-switch-ats-sequence-of-operation/12431 "2024-08-12T13:10:19Z")
The typical sequence of operation for an Automatic Transfer Switch (ATS) is as follows: The ATS permanently measures the electrical parameters such as voltage and frequency, of both the primary and the back-up power… --- ## [What is BusWay? What are the different Types of Bus Ducts?](https://forumautomation.com/t/what-is-busway-what-are-the-different-types-of-bus-ducts/13704)
**Author:** [@Rabert](https://forumautomation.com/u/Rabert)\ **Replies:** 0\ **Last updated:** [November 10, 2025, 8:05am UTC](https://forumautomation.com/t/what-is-busway-what-are-the-different-types-of-bus-ducts/13704 "2025-11-10T08:05:48Z")
What is BusWay? The Bus Way is a prefabricated electrical distribution system made up of distribution rods (copper or aluminum bars) enclosed in a protective metal structure which includes straight lengths, fittings, equ… --- ## [Wireless and Batteryless Push Buttons](https://forumautomation.com/t/wireless-and-batteryless-push-buttons/13556)
**Author:** [@Rabert](https://forumautomation.com/u/Rabert)\ **Replies:** 0\ **Last updated:** [September 19, 2025, 2:23pm UTC](https://forumautomation.com/t/wireless-and-batteryless-push-buttons/13556 "2025-09-19T14:23:11Z")
\[color=#ff0000\] What Are Wireless and Batteryless Push Buttons? \[/color\] \[url= Switch Types & their Working Principle\]\[color=#1E00A3\] Push buttons \[/color\]\[/url\] that are wireless and batteryless use energy harvesting te… --- ## [What is a Microhmmeter Test?](https://forumautomation.com/t/what-is-a-microhmmeter-test/13548)
**Author:** [@Rabert](https://forumautomation.com/u/Rabert)\ **Replies:** 0\ **Last updated:** [September 15, 2025, 11:37am UTC](https://forumautomation.com/t/what-is-a-microhmmeter-test/13548 "2025-09-15T11:37:43Z")
\[color=#ff0000\] What is a Microhmmeter Test? \[/color\] The microhmmeter is a piece of equipment that measures contact resistance in high & medium voltage electrical connections. It applies a large direct current (usually… --- ## [What is a contactor and why is it used?](https://forumautomation.com/t/what-is-a-contactor-and-why-is-it-used/7437)
**Author:** [@ashlin](https://forumautomation.com/u/ashlin)\ **Replies:** 0\ **Last updated:** [November 20, 2019, 7:12am UTC](https://forumautomation.com/t/what-is-a-contactor-and-why-is-it-used/7437 "2019-11-20T07:12:54Z")
What is a contactor and why is it used A contractor can be considered as a power control device, contactors can be seen in electrical equipment which is frequently turned off and on such as lights, and motors. Contactor… --- ## [How to select the right circuit breaker for the specific electrical load?](https://forumautomation.com/t/how-to-select-the-right-circuit-breaker-for-the-specific-electrical-load/13522)
**Author:** [@Rabert](https://forumautomation.com/u/Rabert)\ **Replies:** 0\ **Last updated:** [September 9, 2025, 12:32pm UTC](https://forumautomation.com/t/how-to-select-the-right-circuit-breaker-for-the-specific-electrical-load/13522 "2025-09-09T12:32:34Z")
How do you select the right circuit breaker for a particular electrical load? To choose the appropriate circuit breaker for a specific electrical load, first determine the total load current. The breaker you select m… --- ## [What is the difference between RCCB, RCBO and ELCB?](https://forumautomation.com/t/what-is-the-difference-between-rccb-rcbo-and-elcb/13519)
**Author:** [@Rabert](https://forumautomation.com/u/Rabert)\ **Replies:** 0\ **Last updated:** [September 9, 2025, 9:07am UTC](https://forumautomation.com/t/what-is-the-difference-between-rccb-rcbo-and-elcb/13519 "2025-09-09T09:07:22Z")
What is the difference between RCCB, RCBO and ELCB? \[color=#ff0000\] What is RCCB and its function? \[/color\] An \[url= Difference between MCB, MCCB, RCB & ELCB\]\[color=#1E00A3\] RCCB (Residual Current Circuit Breaker) \[/colo… --- ## [Types of Electrical Connectors](https://forumautomation.com/t/types-of-electrical-connectors/13492)
**Author:** [@Rabert](https://forumautomation.com/u/Rabert)\ **Replies:** 0\ **Last updated:** [August 29, 2025, 11:34am UTC](https://forumautomation.com/t/types-of-electrical-connectors/13492 "2025-08-29T11:34:25Z")
What is Electrical Connector? Electrical Connectors are essential components of electrical and electronic systems, serving as the foundation for safe, dependable and efficient wiring. They act as the link between conduc… --- ## [What is the Earthing Arrangement for an 11kV Double Pole Structure?](https://forumautomation.com/t/what-is-the-earthing-arrangement-for-an-11kv-double-pole-structure/13482)
**Author:** [@Rabert](https://forumautomation.com/u/Rabert)\ **Replies:** 0\ **Last updated:** [August 25, 2025, 4:17pm UTC](https://forumautomation.com/t/what-is-the-earthing-arrangement-for-an-11kv-double-pole-structure/13482 "2025-08-25T16:17:32Z")
Earthing is necessary for assuring the safety of electrical systems and the dependability of the system. Let’s have a look at the most important components and the earthing connections between them: Primary Component… [Next page](https://forumautomation.com/tag/switchgear/93.md?match_all_tags=true&page=1&tags%5B%5D=switchgear)