What is Taco Hydronic System Solutions?

What is Taco Hydronic System Solutions?

Taco Hydronic System Solutions (knowledge of HVAC systems and their design required


What is Taco Hydronic System Solutions?
Taco Hydronic System Solutions is a dynamic, drag-and-drop technology software that assists HVAC designers in the design of hydronic equipment systems, setting of system parameters and the scheduling of HVAC equipment.


Although this program includes default values entered at each data input field, a solid fundamental knowledge of HVAC systems and HVAC systems design is required for proper application of the program.


Taco Hydronic System Solutions Project Files Taco Hydronic System Solutions project files may be saved for reference, shared for review and stored in a library for use on future projects.

Taco TFP & TMP Series Brazed Plate Heat Exchangers

The Taco TFP Series is designed specifically for Domestic Hot Water applications, In-Floor Radiant Heating, Snow-Melt applications, and as a general alternative to Shell & Tube type heat exchangers.The TFP Series is rugged and reliable, yet very compact, representing the latest technology in high-performance heat exchangers. Copper brazed, stainless steel plates offer a highly efficient, low fouling transfer surface. All Taco TFP Series units have male pipe thread fittings, and mounting stud bolts are standard.

Liquid to Liquid Heat Exchangers


Sizing and Selection



Refer to Selection Guide 200-2A for manual selection procedure. Computer selections available through TACO Representatives.



Following data is required:

1. Flow in tubes (GPM).

2. Entering liquid temperature in tubes (°F).

3. Leaving liquid temperature in tubes (°F).

4. Flow in shell (GPM).

5. Entering liquid temperature in shell (°F).
6. Leaving liquid temperature in shell (°F).
7. Fouling factors.
8. Properties of fluids (if other than water).

Requests for sizing and design of custom/industrial heat exchangers may be submitted directly to TACO Engineering Office. Simply select the Process Heat Transfer Icon at Internet home page (taco-hvac.com).

Hydronic Systems Save Energy And Materials.

Both kinds of HVAC systems impact the environment in two ways: 1) Each consumes non-regenerative raw materials in construction. 2) Each consumes energy to operate. Again, hydronic systems win. Advanced LoadMatch single pipe hydronic systems require less raw materials for construction by virtue of a reduction in pipe, fittings, insulation, control valves, and balancing valves. To move BTUs around a building, hydronic systems require about half the energy of a comparable air system, because water has a higher specific heat and higher density than air.

Hydronic Systems Are More Comfortable.

Because of the higher thermal inertia of water, the temperature in a room heated or cooled by hydronics will be more even and thus more comfortable. Additionally, when the room is heated or cooled by a LoadMatch single pipe system, the temperature will be more consistent and, therefore, even more comfortable. A LoadMatch system is self balancing; tweaking balance valves to get the water to the right location in the right quantity isn’t necessary.

Sizing and Selection Steam to Liquid Heat Exchangers

Refer to Selection Guide 200-1A for manual selection procedure. Computer selections available through TACO Representatives.

Following data is required:
1. Steam pressure at heat exchanger.
2. Flow in tubes (GPM).
3. Type of fluid in tubes.
4. Properties of fluids (if other than water).
5. Temperature in.
6. Temperature out.
7. Fouling factor.

Requests for sizing and design of custom/industrial heat exchangers may be submitted directly to TACO Engineering Office. Simply select the Process Heat Transfer Icon at Internet home page (taco-hvac.com).

Get free download Taco Hydronic HVAC system solutions catalog:



Easy Finding Fault Location for HVAC Trouble Shooting: Danfoss Guide


HVAC Fault Location
HVAC fault finding and troubleshooting within a minimal time denotes a HVAC technician efficiency. 

Especially find fault location troubleshooting during system breakdown is very challenging for a HVAC technician.

Hope this trouble shooting fault location guide will be helpful for any beginner as well as experienced technician.

Actually fault finding and trouble shooting has no specific rules that can follow to find the fault location mathematically, performance depends on technician skilled experience to find fault location and trouble shoot in short.

This guide will discuss with some common faults in refrigeration systems, causes of maximum faults and way to easy find out the faulty parts and system of remedy.

However, this guide will buildup a technician to find which types of fault and where occurs the fault in refrigeration system. 

This guide no more deals with electronic control system and their trouble shoot, it will discuss in another article.


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How Find Faulty Parts Easily In Refrigeration System?

There are two main fault in may find in refrigeration system- visible and non-visible.

Visible fault may find with necked eyes, but detect non-visible fault it’s need tools or equipment help.

Visible or recognizable fault can be see like-air cooled condenser, water cooled condenser, receiver with sight glass, receiver stop valve, liquid line, filter drier, sight glass, thermostatic expansion valve, air cooler, liquid cooler, suction line, regulator in suction line, compressor & cooled room etc.;

Fault can be felt, like- solenoid valve & filter drier etc;

Fault can be heard, like- regulator in suction line & compressor etc.;
Fault can be smelled, like- cooled room etc..

Fault finding tools required to find some fault, like refrigeration leakage, temperature deviation etc.

Free Download Easy Guide to Fault Location

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If you feel this article is helpful for you, make helpful for others just sharing and improve this article writing comments below.

Different Types of Electrical Switches and Their Uses

Different Types of Electrical Switches Normally Used in Circuits

There are so many types of electrical switches available from very simple to very complex switches used in electrical circuit controlling system. 

Switch may different types but the basic function of electrical switch is to open or close. The meaning of electrical switch is to open or close the electrical path to equipment. 




What are the different types of electric switches that uses in every home?

When we name the switches, we find some common and lovely switches as below:
SPST Single Pole Single Through SwitchSPST- Single pole, single throw switch. It is simple on-off switch just having  two terminals are either connected together or disconnected from each other by phase P1 and terminal T1.
It is also classified into two types: SPST-NO-single pole, single throw, normally open known as Type-A and SPST-NC- single pole, single throw, normally closed known as Type-B. 

The most common and simple type of electric light switch is the one way switch. A very simple one way press operation and instant effects. Their operational simplicity makes user comfort a reality.


SPDT Single Pole Double Through Switch SPDT-  Single pole, double throw. It is simple break-before-make changeover switch common terminal is connected either to Terminal T1 or Terminal T2.
Similar as SPDT some manufacturer use SPCO/SPTT meaning single pole changeover or single pole, center off or single Pole Triple Throw for switches. 

Two way switches are very much different and are extensively found in modern homes that have limited number of switching accessories. Their usage is very efficient and adds to the convenience of the users significantly.


DPST Double Pole Single Through Switch DPST- Double pole, single throw. DPST actually equivalent to two SPST switches together controlled by a single mechanism.


DPDT Double Pole Double Through Switch
DPDT- Double pole, double throw. DPDT actually equivalent to two SPDT switches controlled by a single mechanism. 

Some manufacturer use DPCO - double pole change over for switches with a stable center position. 

2P6T Two Pole Six Trough Switch

2p6tTwo pole, six throw. 2p6t is actually a changeover switch with a common terminal which can connect to L1 to L6 with a two pole second switch controlled by a single mechanism.




What type of switch is used in an electrical panel?

The switches used in electrical panels may manual switches or automatic switches. The manual operated switches such as light switch, fan switch or manual switch for any kind of electrical circuit of electrical equipment.

Automatically operated different switches can be used to control the motions of machines such as to indicate a door has reached its full open position or full close position.

Switches may be operated by process variables such as pressure, temperature, flow, current, voltage, and force, acting as sensors in a process and used to automatically control a system. There are many different switch designs. The most common electrical panel switches are:




Slide switch: A slide switch has a knob that you can slide back and forth to open or close the contacts. Slide switches we find as SPST (single pole single throw), DPDT (double pole double throw) switch.




Toggle switch: A toggle switch has a lever that we flip up or down to open or close the contacts. The common light switch used in household wiring is an example of a toggle switch.Toggle switches are actuated by a lever angled in one of two or more positions. Most famous type of toggle Electrical Switches contain two positions.






Rotary switch: A rotary switch has a knob that we turn to open and close the contacts. The switch in the base of many tabletop lamps is an example of a rotary switch.







Rocker switch: A rocker switch has a seesaw action. We press one side of the switch down to close the contacts, and press the other side down to open the contacts.


You may read the circuit-switch 

MCB: MINIATURE CIRCUIT BREAKER OPERATION BASIC

Knife switch: A knife switch is the kind of switch Igor throws in a Frankenstein movie to reanimate the creature. In a knife switch, the contacts are exposed for everyone to see.



Mercury switch:The mercury switch consists a drop of mercury inside a glass bulb with 2 contacts. The two contacts pass through the glass, and are connected by the mercury when the bulb is tilted to make the mercury roll on to them.

Push-button switchA push-button is simply button which switch mechanism for controlling some aspect of a machine or a process.  Though even many un-biased buttons require a spring to return to their un-pushed state. These switches are used for bell circuits, refrigerator lighting circuit. Some of push button on industry also contain indication lights such as Red, Green and yellow.



Special types of switches are:

Differential Pressure Switch

Differential Pressure switch: Differential pressure switch is a device which utilizes a differential air pressure to actuate an electric switch at a preset actuation point. This may be the difference between two positive or two negative pressures, one of each, or a positive and atmospheric or a negative and atmospheric pressure. The electric switch may be used to start or stop motors or fans, open or close dampers or louvers, light a warning signal, sound alarms, etc.



Foot Switch



Foot switch: Some machinery like garments factory swing machine use foot switch that operated by foot instead of hand.
Reversing Switch
Reversing switch:Reversing switch is an electric switch that has four terminals capable of being connected in pairs in two different ways so as to reverse the direction of motor.









You may read the different types of switches in details in another articles:


  1. How Select Control Switches, Selector Switches and Auxiliary Switches;
  2. Automatic Transfer Switch Diagram And Operation Procedure;
  3. How Do Electronic Thermostats Work In HVAC System?;


28 Basic Symbol of Electrical Switches that Use Widely

Symbol for electrical switches is important to electricians to select proper switches during wiring.

Following 28 switch-symbol is the most common uses stitches in our work place.


This is not the limit, there are many switches and switch-symbol for them.


You may read the another article to know the detail wiring system on-

ELECTRICAL DISTRIBUTION BOARD DB WIRING.



Symbol of Electrical Switches

Top Brands Electrical Switches that Uses in Bangladesh

Siemens - Huge scale of operation and range, adapted to Bangladesh, electrical switches of Siemens work irrespective of the load, products are reliable. In house Siemens switches and sockets are used as first choose in high grade equipment.


Schneider - French multinational, develops technology and solutions that make energy safe, reliable, efficient, green and productive. Schneider switches and sockets are popular in industry sector.


Legrand -Widely used in Bangladesh as switches and sockets of miniature circuit breakers and distribution boards.

Havells - Indian company, the switches and sockets are widely used in India and Bangladesh.


Wipro - Modular switches are equipped with glossy finish switches flaunt radium markers for visibility at night, protective spark shield for added safety, thermostat housing for safe electrical insulation, and silver coated metal parts for better current conductivity.


Polycab - specializes in high and low voltage switch-gear, different range of solutions that are suitable for all kinds of HV/LV power engineering requirements including protection, metering, and control equipment.


Orpat - Gujarat based company, known for silver series modular switches and copper series modular switches, which are gradually gaining in popularity in the country.


What is the Difference between Isolation and Switching?



The consumer’s main switchgear must be readily accessible to the consumerand be able to:


  1. isolate the complete installation from the supply;
  2. protect against overcurrent;
  3. cut off the current in the event of a serious fault occurring.The regulations identify four separate types of switching: switching for isolation,switching for mechanical maintenance, emergency switching and functionalswitching.

Isolation

 is deļ¬ned as cutting off the electrical supply to a circuit or item ofequipment in order to ensure the safety of those working on the equipment bymaking dead those parts which are live in normal service.

The purpose of isolation switching is to enable electrical work to be carried outsafely on an isolated circuit or piece of equipment. Isolation is intended for useby electrically skilled or supervised persons. 

An isolator is a mechanical device which is operated manually and used toopen or close a circuit off load. An isolator switch must be provided close to thesupply point so that all equipment can be made safe for maintenance. 

Isolatorsfor motor circuits must isolate the motor and the control equipment, and isolatorsfor discharge lighting luminaires must be an integral part of the luminaire sothat it is isolated when the cover is removed or be provided with effective localisolation (IET Regulation 537.2.1.6). 

Devices which are suitable for isolation areisolation switches, fuse links, circuit-breakers, plugs and socket outlets. Theymust isolate all live supply conductors and provision must be made to secure theisolation (IET Regulation 537.2.2.4).

Isolation at the consumer’s service position can be achieved by a double-poleswitch which opens or closes all conductors simultaneously. On three-phasesupplies the switch need only break the live conductors with a solid link in theneutral, provided that the neutral link cannot be removed before opening theswitch.

The switching for mechanical maintenance

requirements is similar to those forisolation except that the control switch must be capable of switching the full loadcurrent of the circuit or piece of equipment.

The purpose of switching for mechanical maintenance is to enable non-electricalwork to be carried out safely on the switched circuit or equipment.

Mechanical maintenance switching is intended for use by skilled but non-electrical persons. Switches for mechanical maintenance must be manuallyoperated, not have exposed live parts when the appliance is opened, must beconnected in the main electrical circuit and have a reliable on/off indication orvisible contact gap (IET Regulation 537.3.2.2). 

Devices which are suitable forswitching off for mechanical maintenance are switches, circuit-breakers, plugand socket outlets.

Emergency switching

 involves the rapid disconnection of the electrical supplyby a single action to remove or prevent danger.The purpose of emergency switching is to cut off the electrical energy rapidly 
 toremove an unexpected hazard.Emergency switching is for use by anyone. 

The device used for emergencyswitching must be immediately accessible and identiļ¬able, and be capable ofcutting off the full load current.

Electrical machines must be provided with a means of emergency switching,and a person operating an electrically driven machine must have access to anemergency switch so that the machine can be stopped in an emergency. 

Theremote stop/start arrangement could meet this requirement for an electricallydriven machine (IET Regulation 537.4.2.2). Devices which are suitable foremergency switching are switches, circuit-breakers and contactors. 

Wherecontactors are operated by remote control they should open when the coil isde-energized, that is, fail safe. Push-buttons used for emergency switching mustbe coloured red and latch in the stop or off position. 

They should be installedwhere danger may arise and be clearly identiļ¬ed as emergency switches.Plugs and socket outlets cannot be considered appropriate for emergencydisconnection of supplies.

Functional switching

 involves the switching on or off, or varying the supply, ofelectrically operated equipment in normal service.The purpose of functional switching is to provide control of electrical circuits andequipment in normal service.Functional switching is for the user of the electrical installation or equipment.

The device must be capable of interrupting the total steady current of the circuitor appliance. When the device controls a discharge lighting circuit it musthave a current rating capable of switching an inductive load. 

The regulationsacknowledge the growth in the number of electronic dimmer switches beingused for the control and functional switching of lighting circuits. The functionalswitch must be capable of performing the most demanding duty it may be calledupon to perform (IET Regulations 537.5.2.1 and 2)

Freeze Protection Pro Cooling System

freeze protection pro cooling system
Fig: Freeze protection pro cooling system diagrum

The freeze protection pro cooling system

Solidifying or Freezing is one of most imperative vocabulary in cooling framework; because of solidifying in cooling framework liquid stream blocked, metallic channel broke, supplies cracked and so on, trouble happened. To keep nonstop sheltered and sound fluid stream solidify assurance then again against solidifying framework is required both in re-flowed water framework and shut circuit liquid cooler framework.

Freeze protection for re-circulating water system:

The least difficult and best method for keeping the re-flowed water from solidifying is to utilize a remote sump. With a remote sump, the re-coursing water pump is mounted remotely at the sump and at whatever point the pump is closed off, all re-flowing water channels back to the sump. 

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In the event that a remote sump can't be utilized, dish radiators are accessible. Either electric radiators, boiling point water loops, steam curls or steam injectors might be utilized to warm the bowl water when the unit is closed down. Nonetheless, the bowl radiator won't keep the outer water lines, pump or pump channeling from solidifying. The make-up water supply, flood and deplete lines, and additionally the pump and pump speaking up to the flood level must be warmth followed and protected to shield them from harm.

A condenser or cooler can't be worked dry (fans on, pump off) unless the water is totally depleted from the container. The container warmers are measured to keep skillet water from solidifying just when the unit is totally closed down.

Freeze Protection of Closed Circuit Fluid Cooler Coils:

The least difficult and best method for shielding the warmth exchanger curl from solidifying is to utilize a repressed ethylene glycol liquid catalyst. In the event that this is impractical, an assistant warmth load must be kept up on the curl at all times so that the water temperature does not drop underneath 50F when the cooler is closed down. A base prescribed stream rate ought to likewise be kept up.

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On the off chance that a radiator fluid arrangement is not utilized, the loop must be depleted promptly at whatever point the pumps are closed down or stream stops. This is expert via programmed channel valves and air vents in the funneling to and from the cooler. Care must be taken to guarantee that the channeling is enough protected and estimated to permit the water to stream rapidly from the loop. This strategy for assurance ought to be utilized just as a part of crisis circumstances and is neither a functional nor prescribed technique for stop insurance. Curls ought not be depleted for a developed timeframe.

At the point when the unit is in operation amid solidifying climate, some sort of limit control is ordinarily required to keep water temperatures from dropping underneath 50F. Working dry with a remote sump is an amazing method for diminishing unit limit at low temperatures. Different strategies for limit control incorporate two velocity engines, VFDs, Fan cycling and fan dampers (on constrained Draft units as it were). These can be utilized separately or as a part of blend with dry/Remote sump operation.

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Trust this article on stop security framework ace cooling framework will help you to run the cooling plant and recoup the framework in the blink of an eye if down the framework due to solidifying.
 

Why Transformer Tap Changing is Required?

What is the Principal of Transformer Tap Changers?
Fig-Transformer Tap Changers Line Diagram

What is the Principal of Transformer Tap Changers?

We will try to understand the principle of transformer tap changer andtry to find the answer of question- Can a transformer be tapped when it is on a load? Why is a tap changer used in an HV side?

A tap changer is a mechanism in transformers which allows for variable turn ratios to be selected in discrete steps. Transformers with this mechanism obtain this variable turn ratio by connecting to a number of access points known as taps along either the primary or secondary winding.

A tap is a connection point along a transformer winding that allows a certain number of turns to be selected. This means, a transformer with a variable turns ratio is produced, enabling voltage regulation of the output. The tap selection is made with a tap changer mechanism.

You may like to read another post about: 





Can a transformer be tapped when it is on a load?

Yes.
Yes, on load tap changers are in use to adjust the output voltage of power transformers since long. OLTC are attached to the power transformers. Control cables run from OLTC to panel in the control room and it can be operated auto /manual.

Variable autotransformers like Variacs and Power-stats have a sliding contact that allows them to effectively change the tap point by turning a knob while they are under load.

Many power utility systems have large, high power tap changers that can change the tap point of a distribution transformer under load to compensate for varying demand conditions.

There are two (perhaps three) types of tap changer available, and the difference lies in the question you ask.

Off-load tap changer, sometimes called offline. Which requires load disconnection before the contacts move. There is usually a downstream breaker to interrupt the load during tap changing.

On load tap changer (make before break) . The contacts are designed to have a shorting piece, and to make contact with the next tap, before relinquishing contact with the first. The shorting piece has to be resistive, to avoid a shorted turn.

On load tap changer (break before make). This is not really onload, but the break during tap changing is very short indeed. The contacts very nearly bridgeacross two taps but not quite. No resistance is needed. Interruptions of 0.1 hallf cycles can easily be achieved.

The first type is rarely automated, the second two normally are.

The construcion of each is very different, so they cannot be used ith swopped duty.


 Why is a tap changer used in an HV side?

In this type the tap changer circuit is placed in primary side or supply side. As we know;


    Turns ratio        = secondary winding turns (Ns)/ primary winding turns (Np)= Ns/Np.

           Secondary voltage = (supply voltage or primary voltage) / Turns ratio.
It is mainly due to the current magnitude. The HV side has higher voltage than the LV side but lower current than the LV side.

You want as low current as possible to be handled by your tapchanger and,hence,the logical choice of installing the tapchanger on the winding side with the lower current (i.e HV side).

Transformer Tap changer on Primary Side or HV side:


1) In normal operation the tap changer will be at 0% position to provide required designed secondary voltage.



2) If the supply voltage increases or load current decreases there will be an increase in supply voltage which is not desirable. At this case the tap position in the primary winding will rise towards positive direction i.e. +2.5%, and hence decreases the Np. This will increases the turns ratio (Ns/Np) further decreases the secondary voltage.



Safety Operation of Medium Voltage Switchgears

Safety Operation of Medium Voltage Switchgears

Hazards of operating on electrical equipment


Medium-voltage switchgear. Eaton's medium-voltage switchgear provides centralized control and protection of medium-voltage power equipment and circuits in industrial, commercial, and utility installations involving generators, motors, feeder circuits, and transmission and distribution lines. There are five kinds of hazards related to the operation of electrical equipment.
  1. Electrical shock
  2. Electrical burns
  3. Fire and explosion
  4. Heat build up
  5. Mechanical hazards
  6. Electrical shock
Because there may be a serious threat of flashover, shock, arcing, etc. when working in a medium voltage environment, decrease voltages tend to be handled with less admire. It need to be remembered that a voltage as low as 50 V, with a contemporary of ± 30 mA, can reason asphyxia and/or heart muscle fibrillation. The biggest hazard of strength is that live and dead apparatus are indistinguishable from each other. Therefore, equipment ought to in no way be assumed lifelessconstantly presume it's far alive. This can simplest be ascertained by checking out with the appropriate accepted tester, or by using the presence of a visible earth connection. Electricity can bounce gaps, which means that that it isn't even important to the touch a medium voltage conductor so as to get hurt. Merely approaching too near may have fatal results, thereforeit's far important to preserve close proximity distances.
  1. Identify the proper substation/MSS etc.
  2. Identify the best circuit breaker/ isolator.
  3. Switch – open the circuit breaker/ isolator.
  4. Isolate the circuit breaker with the aid of racking out/ down.
  5. Test – the use of accepted voltage detector.
  6. Earth – connect correctly to earth the use of correct method.
Mini sub stations (MSS) and ring fundamental panels (RMP) are opened manually the usage of the ideal working handle. The “T” off to the transformer may be furnished with a circuit breaker or fuses and opened through pushing a button on the the front of the unit. They also can be provided with an electrical remote operating device, similar to a circuit breaker. Isolate Isolution mains bodily disconnecting the equipment from all feasible resources of electrical potential by using:
  1. Opening and/or putting off of fuses.
  2. Opening of links.
  3. Withdrawal of truck type switchgear.
  4. Lock off and apply risk tags.

Security at factors of isolation:

All points of isolation ought to be locked off through the application of a non-public lock to prevent inadvertent operation of the mains or equipment. Danger tags: The use of threat tags is an essential part of the isolation process. Danger tags need to be carried out on the transfer or control equipment which has been remotedwith the intention to enable men and women to paintings on electrical equipment or conductors safely, by way of notifying people that paintings is being conducted on that piece of apparatus

Authorised character

individual advocated via the electrical engineer or his nominee and appointed in writing with the aid of the designated individual to perform switching, isolating, testing and earthing on electric mains and apparatus, in liaison with and beneath the practise of a manipulate officer and to trouble work permits in recognize of such mains and equipment

Isolation technique 

The authorised person shall perform the necessary isolations, using personal locks,  onsistent with the policies and regulations. Thereafter, perform safety tests the usage of an appropriate authorised tester to make sure that the mains and/or equipment are useless and apply risk tags at all control points.

Control factor:

function at the system where a major and/or apparatus may be switched, isolated, and earthed. When isolating, the equipment should be isolated, from all viable resources of electricitynot just energy. Therefore, we need to keep in mind the subsequent sources of hazardous strength and hazardous substances.

Hazardous strength:

Electrical, pneumatic, hydraulic, stored (springs, batteries), ability (via distinctive feature of position), heat (hot water, steam), radiation.

Hazardous substances:

Gases, vapours, liquids, dusts with the ability to purpose injury or illness, e.G. Toxic, corrosive, flammable. All plant and system need to have written methods for isolation; these approaches will set out a step by step account of the way the gadget, plant or system is to be remoted and kept secure. In the case of electrical isolation, a check for voltage should be performed with the ideal approved tester, to make sure that the mains and/or equipment are dead.

Summary

The authorised character plays the isolation in line with the regulations and regulations. Control factors need to be locked off the usage of private locks. Danger tags ought to be implemented to all factors of isolation.

The locking of manipulate factors and alertness of risk tags is crucial for a safe isolation, and isolation will not be deemed complete till those necessities are met.

Locking off of stay shutters

All stay shutters ought to be locked off with the personal lock. Cable shutters must be classed as stay shutters, as the cable might be returned fed, e.G. Open factor on a hoopconsequentlyboth bus bar and cable shutters should be locked off.

Test
Before applying earthing device, the conductor have to first be tested to prove it lifeless. Before the use of any approved medium voltage system it have to be physically inspected for defects. When testing medium voltage the 3 factor take a look at have to be adopted, test the tester on a known stay source or a check box furnished with the aid of the manufacturer, test all 3 levels and retest the tester.

There are several sorts of voltage testers on the market and they all have particular uses:

Voltage detector (live tester): 
Used for testing the presence of voltage. A live tester is one that has to the touch the conductor underneath take a look at if you want to decide if it's far stay or useless (it is recommended that one with audible and visible annunciation is used). These live testers are synthetic in two distinct types – S and L. S kind to be used on switchgear. L type for use on overhead lines.

Phase comparator/phasing sticks (live tester):

Used to test that circuits are in segment with every other. A phase comparator have to be used for phase contrast and now not voltage detection.

Phasing in of ring feeds
It is vital to segment in medium voltage system prior to energising cable circuits, to make certain the appropriate segment rotation whilst cable systems are maintained and extended. Electrical phasing have to be carried out while:
  1. New system is installed, which necessitates breaking into a ring feed, e.G. New substations.
  2. After the repair to any cable which forms part of a hoop feed.
  3. Whenever a cable which forms a part of a ring feed is terminated.
  4. An existing cable (to be again to service) is being joined and/or terminated.

Voltage detector (proximity tester):

Used on overhead lines. This tester does now not must come into contact with the conductor below take a look at to determine if it's far live or dead, it detects the magnetic field and consequently best works on naked and unscreened conductors.

There are no test facilities to test the cable is useless before earthing on an MSS/RMP, howevermaximum modern units are supplied with LEDs, indicating if the cable is live or useless and these should be used as a guideline whilst operating. They additionally have the ability for doing electrical phasing on the front of the unit, using a multimeter. MSS/RMPs do have take a look at pointshowever these are for checking out the cable as soon as it's been earthed and consequently get admission to can only be won to them once the cable has been earthed.

Earthed
Connected to the overall mass of earth in such a way as to make sure always an immediate safe discharge of power. There are several special forms of earthing methods: fundamental earthing, earthing carriage, earthing truck, and transportable earths. Integral earthing is designed into the circuit breaker and no outside attachments should be implemented to the circuit in order to earth it.

Earthing bus bars

When earthing a bus bar all viable assets of deliver must be isolated. Therefore:
All far flung ends ought to be switched, isolated, locked off and threat tags carried out.

All nearby circuit breakers must be switched, remoted, locked off and hazard tags applied.

Test with an accepted voltage detector.
Apply no less than one earth. Portable earthing device A p p l i c a t i o n o f p o r t a b l e e a rt h i n g system:
  1. The mains and/or equipment to be earthed ought to be tested with an authorised voltage detector to ensure that it's far dead.
  2. Check the condition of the portable earths
  3. Securely connect the flexible cause an earth bar or earth conductor FIRST.
  4. Using an earth or hyperlink stick touch every segment of the mains and/or apparatus to be earthed.
  5. Clamp onto every section.
  6. When casting off the portable earths theearth connection need to be eliminated last.
  7. Care must be taken to make certain exact tight connections. It is the authorised character’s responsibility to ensure that all portable earths are removed earlier than energising the circuit.

Interlocs

All circuit breakers and MSS/RMPs have mechanical interlocks, for example, you can't rack a circuit breaker out if it's miles closed, you'll no longer have the ability to region an earth on an RMP unless it's been opened first. However, they're no longer interlocked with each other and it is feasible to earth a live cable. To this ceasethe ideal oprating method ought to be accompanied and the authorised individual need to ask himself, earlier than operating, what impact will the operation I perform have at the rest of the device – for every action there's a reaction! The following is a listing of a number of the matters to remember earlier than working:

Switch (open)

Will any deliver be misplaced? If so, can I reroute the supply (shift open point on the ring, or shift load onto any other circuit).
  1. If load has been shared with some other circuit, make sure that that circuit can convey the blended load.
  2. If load has been shared with any other circuit, ensure that that circuit has picked up load before starting the circuit breaker.
  3. Once the circuit breaker has been opened, take a look at the other circuit has picked up the full load.
  4. Can the circuit breaker be opened remotely, if not what PPE is required?
  5. On a MSS/RMP the LEDs may be used to see if supply is lost to different circuits and to test if the circuit is lifeless.

Isolate
Have all 3 phases on the circuit breaker opened?
Before racking out/down a circuit breaker, it is right practice to test all three phases are now not drawing load, this could be done via the usage of the ammeter selector switch, if one is fitted.

Test
Is the tester suitable to be used at the system? E.G. correct kind and voltage rating.

Is the tester in exact circumstance?
There are no check facilities (NTF) on a MSS/RMP prior to earthing.

Earth
Is the opposite facet of the circuit opened and isolated or earthed?
When reinstating the circuit

Remove earths
There is no electrical tripping in the earth function on a circuit breaker, so the circuit breaker needs to be tripped manually.

Close
Has the earth been eliminated on the faraway stop?
  1. Has the far off end been made safe? E.G. Has the area been checked after paintings that there no tools were left inside the operating place. Have employees been warned it's miles now not safe to work within the place. Have portable working earths been eliminated etc.
  2. Has the remote cease been secured? E.G. Has it been isolated and locked off?
Work allows

Written authorisation for work to be accomplished on electrical mains and/or apparatus. Once the circuit has been made safe for paintings as above, the authorised person will difficulty a medium voltage work permit for work to be performed on the remoted mains and/ or equipment. It is crucial when issuing a work permit the following interaction with the character in fee is executed:
  1. Give explicit instructions to the individual in price of the paintings regarding the paintings to be performed and the secure limits of the workplace and make certain that this is understood.
  2. Show the person in price the manage points and permit him/her to location their non-public lock at the manage point.
  3. Earth or show the mains/equipment dead on the worksite.

When receiving the work permit returned on the place of job from the person in fee, the authorised person is answerable for acquiring confirmation that each one persons are clear of the mains and/or equipment and that each one non-public running earths implemented at some point of the work were removed.