Category 5 cable

Category 5 cable
From Wikipedia, the free encyclopedia

Cat5 patch cable

Category 5 cable, commonly known as Cat 5 or "Cable and Telephone", is a twisted pair cable type designed for high signal integrity. Many such cables are unshielded but some are shielded. Category 5 has been superseded by the Category 5e specification. This type of cable is often used in structured cabling for computer networks such as Ethernet, and is also used to carry many other signals such as basic voice services, token ring, and ATM (at up to 155 Mbit/s, over short distances).

Usage and wiring methods

Category 5

The specification for category 5 cable was defined in ANSI/TIA/EIA-568-A, with clarification in TSB-95. These documents specified performance characteristics and test requirements for frequencies of up to 100 MHz.
Category 5 cable includes four twisted pairs in a single cable jacket. This use of balanced lines helps preserve a high signal-to-noise ratio despite interference from both external sources and other pairs (this latter form of interference is called crosstalk). It is most commonly used for 100 Mbit/s networks, such as 100BASE-TX Ethernet, although IEEE 802.3ab defines standards for 1000BASE-T - Gigabit Ethernet over category 5 cable. Cat 5 cable typically has three twists per inch of each twisted pair of 24 gauge copper wires within the cable.

Category 5e

Cat 5 e cable is an enhanced version of Cat 5 that adds specifications for far end crosstalk. It was formally defined in 2001 as the TIA/EIA-568-B standard, which no longer recognizes the original Cat 5 specification. Although 1000BASE-T was designed for use with Cat 5 cable, the tighter specifications associated with Cat 5e cable and connectors make it an excellent choice for use with 1000BASE-T. Despite the stricter performance specifications, Cat 5e cable does not enable longer cable distances for Ethernet networks: cables are still limited to a maximum of 100 m (328 ft) in length (normal practice is to limit fixed ("horizontal") cables to 90 m to allow for up to 5 m of patch cable at each end). Cat 5e cable performance characteristics and test methods are defined in TIA/EIA-568-B.2-2001.

Connectors and other information

The cable exists in both stranded and solid conductor forms. The stranded form is more flexible and withstands more bending without breaking and is suited for reliable connections with modular connectors, but makes unreliable connections in insulation-displacement connectors. The solid form is less expensive and makes reliable connections into insulation displacement connectors, but makes unreliable connections in modular connectors. Taking these things into account, building wiring (for example, the wiring inside the wall that connects a wall socket to a central patch panel) is solid core, while patch cables (for example, the movable cable that plugs into the wall socket on one end and a computer on the other) are stranded. Outer insulation is typically PVC or LSOH.
Cable types, connector types and cabling topologies are defined by TIA/EIA-568-B. Nearly always, 8P8C modular connectors, often incorrectly referred to as "RJ-45", are used for connecting category 5 cable. The specific category of cable in use can be identified by the printing on the side of the cable.
The cable is terminated in either the T568A scheme or the T568B scheme. It doesn't make any difference which is used as they are both straight through (pin 1 to 1, pin 2 to 2, etc); however mixed cable types should not be connected in series as the impedance per pair differs slightly and could cause signal degradation. The article Ethernet over twisted pair describes how the cable is used for Ethernet, including special "cross over" cables.

Electrical characteristics for Cat.5e UTP

MAKE TEAM EFFORT

MAKE TEAM EFFORT
THERE is no fixed style of leadership to get things done. Leadership styles must suit the demands of the situation and bosses should be able to change their approach when required.
Remember, the way you achieve your results as a leader is not just by what you do, but rather by what your people do.
In this hyper-speed global economy, the relationship between bosses and employees has changed. Employees now must take personal responsibility for the company’s competitiveness.
They have to accept the reality that their future and the attractiveness of their jobs are directly tied to the company’s performance.
As a leader, you should gain the respect of your subordinates. You may not always be liked, because many decisions that effective leaders need to make may be unpopular with at least some of the people. Cultivate an ethical culture.
A few bad apples can very quickly bring your company to its knees, especially if your organisation depends on intellectual capital.
Every action you take must demonstrate your ethical values. Your team members will take the cue from you, even if you don’t think they are watching you.
It is important that you identify the strengths and weaknesses of every member of your team. You can slot them in one the following groups:

Water-walkers: This group consists of capable, intelligent and quick-thinking people. Take care of them. They can go right across the street and get paid more than what you are currently paying them.

Speed-breakers: Your speed- breakers are those who will readily give you the reasons why a new idea won’t work out without even exploring alternatives. They slow down the progress of the entire organisation. Move them away from departments such as corporate planning and product development.

Actors: These people put up a show in your presence and project themselves as performers, when actually they are not. The sooner you identify them, the better it is for group morale and productivity.

Routine specialists: They carry out all the routine, mundane activities and keep themselves occupied. They meticulously follow procedures. Use them for back-end jobs. But make sure they are efficient in what they do.

Apart from understanding what your employees are capable of, you should also keep the following guidelines in mind. They will, help you to perform better as a leader.

Don’t let crisis manage you: You will be a more effective leader when you show that you can handle a crisis without losing control-of the situation.

There is no room for gossip: Gossip is a destructive force and undermines other people in the workplace. Even listening to gossip creates a hostile environment.

Concentrate on the big picture: If a company wishes to create value and win additional business, then it is not a matter of whether to change. What is important is how fast and how often to do so. Leaders worry less about specific parts and more about the whole.

Watch your moods: Be aware of how your moods and emotions affect other people. Every word, every nuance, every gesture by the leader is interpreted by almost everyone. Every action you take as a leader almost always has an unintended side effect. How you feel is your choice. Don’t give that choke away.

Communicate core values: Make sure that your values are evident to all stakeholders. Align the organisation’s values and practices to those of the employees.

Don’t focus on negative things: Don’t use your mental energy to always look for the negative aspect of things. Always try to find the. good in the bad.

Have a vision: Without a goal, there is no focus. Vision gives meaning to why you belong to an organisation. It answers the question, ‘Where are we going?’ A mutual vision that states where you are headed gives your people responsibility for getting the organiastion to where you want it to be.
People in an organisation come together without any real sense of connection. They are in their own separate worlds with their own priorities. You have to bring them together by making them share a common vision. Leadership is a partnership and not a solo performance.

- Source: ST/ANN The Star, Saturday 22 March 2008
• Article by N.S Kumar, an execufive consultant with the Management Development Institute of Singapore

Mechanical Relay

Mechanical Switching - Relays
A relay consists of an electromagnet (a coil around a iron bar) that can automatically cause one or more switches to move between to contacts. When current is applied to the electomagnet the switch moves towards the magnet, otherwise the switch is in its "normal" position. By wiring one of the switches into the electromagnetic circuit the relay can be made to remember and thus act as a storage device. In general a relay can be used to make other switches in second and third circuits to move.



From http://www.howstuffworks.com

A relay is so-called since it "relays" or copies an action at one point to another. With simple modifications a relay can duplicate a single action into multiple copies, and even remember an action, thus creating a simple memory device.

Cable Outer Sheath PVC vs PE

Polyvinyl Chloride (PVC)

Polyvinyl chloride is basically a hard thermoplastic, but by blending with certain plasticisers a range of general purpose flexible cable compounds of varying degrees of softness can be produced. By the use of selected plasticisers and other additives, grades of PVC can be made which are suitable for either hot or cold ambient temperatures.

Properties

Polyvinyl chloride is a good general purpose thermoplastic. It has good mechanical and ageing properties, and excellent resistance to ozone and weather. It is preferable to pigment it with carbon black to obtain optimum resistance to the effects of sunlight.

Cables insulated and sheathed with PVC will operate satisfactorily when exposed to or immersed in salt or fresh water. Standard PVC compounds are reasonably flame retardant and this property can be improved by special compounding techniques. In general PVC has good resistance to chemicals but affected by solvents and some oils which tend to leach out of the plasticiser and thus cause embrittlement. The so-called 'Heat resisting' grades of PVC have good ageing characteristics at elevated temperatures, but suffer in common with general purpose grades of the tendency to deform under pressure as the temperatures approaches the melting point of the PVC (approx. 130°C). The insulation resistance of PVC is lower than that of some plastics but more than adequate for most wiring applications.

Compared with elastomers, PVC and other thermoplastic materials are susceptible to temperature variations, and they become progressively less flexible as the ambient temperature is lowered.

In general PVC cables should not be installed when the temperature is below 0°C unless the cables have been stored above this temperature for the previous 24 hours. Failure to observe this precaution may result in cracking or shattering of the PVC.

Uses

PVC is used extensively for general wiring cables, low voltage mains cable, domestic flexibles, telephone cable and instrument wiring. It is widely used as a corrosion resistant coating over lead and aluminium sheathed cables.

The maximum continuous operating temperature of general purpose compounds is specified as 70°C and for heat resisting grades as 85°C.

Polyethylene (Polythene)

Polyethylene is a thermoplastic obtained by the polymerisation of ethylene. Depending on the particular polymerisation technique used, polyethylene of varying densities and molecular weight can be produced, and these can therefore be broadly classified as either low or high density polyethylene.

Properties

Polyethylene has extremely good electrical characteristics and excellent resistance to water, chemicals and some solvents. However, it has only moderate resistance to oils and has the disadvantage of being flammable. The low temperature properties of polyethylene are good. It is customary to pigment with carbon black both high and low density polyethylene, to improve their resistance to weather. Polyethylene is an excellent insulation for high voltage cables, but when extruding thick layers of dielectric, care has to be taken to prevent the inclusion of voids during this process. Polyethylene has a melting point of about 110°C-115°C which is a serious disadvantage for cables liable to be subjected to short circuit and overload conditions; this is one of the reasons why the use of this material has discontinued for the insulation of general wiring cables.

Uses

Polyethylene is extensively used either in the solid or expanded form for the insulation of communication cables. One major application is for the insulation of coaxial cable for television downleads, and another is for the insulation of multicore telephone cables where its excellent electrical properties enable a thin small radial wall of insulation to be employed. Polyethylene is used for submarine cables and in some types of high voltage cables. High density polyethylene can be used as an external sheath on cables to provide corrosion protection.

The recommended continuous operating temperature of polyethylene is normally stated as 70°C, to allow a factor of safety for overloads up to a maximum temperature of 90°C.

COMPARISON OF GRP/FRP CABLE TRAYS V/S METAL CABLE TRAYS

1.Corrosion Resistance
GRP/FRP - Excellent corrosion resistance against sea water and most chemical fumes

METAL - Poor corrosion resistance, pitting takes place even in SS or aluminum in sea water. Galvanic Corrosion takes place between Stainless Steel trays and MS supports

2.Hot Working
GRP/FRP -No Hot working, all assembly by Nut & Bolts

METAL -Hot working , welding cutting and joining requires special permission in hazardous areas

3.Light weight
GRP/FRP -Sp.gr. 1.9, 1/4th that of steel, even lighter than Aluminum(sp.gr.2.8), just one person required to lift a big size cable ladder, so very easy and fast Installation, saving time and money

METAL -Very heavy, 4 times to GRP/FRP, hence crane or 3 people required to lift a cable ladder

4.Fire Retardant
GRP/FRP -Meets most stringent offshore fire resistance norms as per British, ASTM and UL specifications

METAL -In heavy fire even steel de-shapes and needs replacement

5.Installation Cost
GRP/FRP -Very low, as lighter in wt hence only one man can lift, and very easy to cut and fabricate at site, thus faster installation and easy site adjustment and modifications

METAL -HIGH, needs 2-3 persons or special equipment to lift, also difficult to cut and refabricate as per site requirement as cutting takes time.

6.Risk of cable damage
GRP/FRP -Very low, as being plastics have much less hardness and even its sharp edges cannot damage a cable

METAL -When any site modification is done, sharp edges are created in metal which can cause damage to cables and pose risk of current.

7.High insulation ands Safe
GRP/FRP -No earthing of cable tray is required as it has high Insulation value. In case of any cable stripping, the tray being Insulated is safe for the Humans.

METAL -Earthing is must, hence cost of earthing increases overall cost, which is not generally considered when evaluating.

8.Part consolidation
GRP/FRP -As GRP/FRP is extruded section, inbuilt ribs for reinforcement, collars for fixing covers are possible in single section

METAL -This is not possible in metal, and if welding is done it looks very bad.

9.U.V. resistance
GRP/FRP -All GRP/FRP cable Trays are made from very high U.V. additives, in addition to special surfacing Veils for glass blooming prevention, and carbon black for additional U.V protection

METAL -N/A

10.Antistatic
GRP/FRP - Cable trays are available in antistatic option as well for oil hazardous areas on demand, thus safe even in hydrocarbon atmosphere.

METAL -N/A

11.First Time COST
GRP/FRP - FRP/GRP cable trays are competitive to SS trays with all above advantages

METAL -SS trays are very costly compared to GRP/FRP Trays

FRP or GRP Cable Ladder/Tray

General
Known as glass-reinforced plastic (GRP) in Britain, fibre-reinforced plastic (FRP) in the USA, or by the trade name fibreglass (after the manufacturing company Fibreglass Ltd.), GRP has been used for a wide range of applications from car body panels and boat hulls to furniture and tennis rackets. It has the virtue of a good weight to strength ratio, rust resistance, and ability to be moulded in a wide variety of ways. It became increasingly widely used in the post-Second World War period, a pioneering design being the celebrated DAR Armchair by Charles and Ray Eames for the 1948 Low-Cost Furniture Design Competition at the Museum of Modern Art in New York. Very much paralleled by the organic forms found in much contemporary product, train, and automobile design in Italy, the flowing, sculptural form of the seat (supported on a metal frame) expressed the creative possibilities of the new medium. These were realized in subsequent designs such as Eero Saarinen's elegant Tulip armchair of 1956. Verner Panton was another designer to explore the expressive qualities of the medium in his moulded, cantilevered chair of 1960 first manufactured in West Germany. Many furniture designs first manufactured in GRP have subsequently been manufactured in ABS plastic. Early use of GRP in automobile manufacture included the roof of the Citroen DS (1955) and the body panels of the Chevrolet Corvette (1953). From the 1970s improved production processes engendered more widespread uses in architecture and interior design, whether in terms of weather resistant details and services or bathrooms.





Definition of FRP Composites


Not all plastics are composites. In fact, the majority of plastics today are pure plastic, like toys and soda bottles. When additional strength is needed, many types of plastics can be reinforced (usually with reinforcing fibers). This combination of plastic and reinforcement can produce some of the strongest materials for their weight that technology has ever developed...and the most versatile.

Therefore, the definition of a fiber-reinforced polymer (FRP) composite is:
A combination of

- a polymer (plastic) matrix (either a thermoplastic or thermoset resin, such as polyester, isopolyester, vinyl ester, epoxy, phenolic)

- a reinforcing agent such as glass, carbon, aramid or other reinforcing material


such that there is a sufficient aspect ratio (length to thickness) to provide a discernable reinforcing function in one or more directions. FRP composite may also contain:

- fillers

- additives

- core materials


that modify and enhance the final product. The constituent elements in a composite retain their identities (they do not dissolve or merge completely into each other) while acting in concert to provide a host of benefits ideal for structural applications including:

High Strength and Stiffness Retention - composites can be designed to provide a wide range of mechanical properties including tensile, flexural, impact and compressive strengths. And, unlike traditional materials, composites can have their strengths oriented to meet specific design requirements of an application.

-Light Weight/Parts Consolidation - FRP composites deliver more strength per unit of weight than most metals. In fact, FRP composites are generally 1/5th the weight of steel. The composite can also be shaped into one complex part, often times replacing assemblies of several parts and fasteners. The combination of these two benefits makes FRP composites a powerful material system- structures can be partially or completely pre-fabricated at the manufacturer's facility, delivered on-site and installed in hours.

-Creep (Permanent Deflection Under Long Term Loading) - The addition of the reinforcement to the polymer matrix increases the creep resistance of the properly designed FRP part. Creep will not be a significant issue if the loads on the structure are kept below appropriate working stress levels.

-Resistance to Environmental Factors - Composites display excellent resistance to the corrosive effects of:
-Freeze-thaw: because composites are not attacked by galvanic corrosion and have low water absorption, they resist the destructive expansion of freezing water.

-Weathering and Ultra-Violet Light: FRP composite structures designed for weather exposure are normally fabricated with a surface layer containing a pigmented gel coat or have an ultraviolet (UV) inhibitor included as an additive to the composite matrix. Both methods provide protection to the underlying material by screening out UV rays and minimizing water absorption along the fiber/resin interface.

-Chemicals and Temperature: Composites do not rust or corrode and can be formulated to provide long-term resistance to nearly every chemical and temperature environment. Of particular benefit, is composites ability to successfully withstand the normally destructive effects of de-icing salts and/or saltwater spray of the ocean.



-Fire Performance of Composites - FRP composites can burn under certain conditions. Composites can be designed to meet the most stringent fire regulations by the use of special resins and additives. Properly designed and formulated composites can offer fire performance approaching that of most metals.

Proses membuat Instrument Location Plan

Langkah-langkah untuk menghasilkan Instrument Location Plan secara manual

1. perlu dapatkan Equipment Layout sebagai background
2. dapatkan Piping General Arrangement (GA) untuk mendapatkan kedudukan Instrument tapping point
3. Information dari Piping GA dipindahkan ke Equipment Layout
4. P&ID digunakan untuk menyemak / memastikan segala process instrument dilakarkan diatas Instrument Location Plan

Langkah-langkah untuk menghasilkan Instrument Location Plan dengan menggunakan Model 3D

1. perlu dapatkan Equipment Layout sebagai background
2. Instrument Tapping point dan Instrument Location perlu di “extract” dari Model 3D dan di”superimpose”kan keatas Equipment Layout.
3. P&ID digunakan untuk menyemak / memastikan segala process instrument dilakarkan diatas Instrument Location Plan

Wiring Diargram

Tujuan utama wiring diagram adalah untuk memberi panduan kepada site technician untuk menjalankan kerja pendawaian dan termination. Semestinya site technician mengharapkan satu drawing yang mempunyai semua maklumat yang deperlukan olehnya dalam bentuk yang jelas dan mudah difahami.

Point-to-point wiring diagram adalah perlu untuk membantu technician yang tidak mahir atau kurang pengalaman melakukan kerja termination dengan betul dan tanpa was-was. Drawing untuk cable termination di Control panel atau terminal box, thermocouple connections dekat JB atau interconnection instrument di belakang panel.

Didalam wiring diagram maklumat berikut mestilah dimasukan:
· Terminal number
· Wire number
· Cable number
· JB/ Cabinet/Panel tag
· Warna wire

Maklumat lain jika dirasakan boleh membantu kerja technician maka perlulah dimasukan.

Wiring diagram adalah berbeza dengan schematic diagram. Wiring diagram menunjukan susun atur secara fizikal tanpa memberi penekanan kepada fungsi satu-satu signal. Manakala schematic diagram lebih menekankan kepada fungsi sesuatu system.

Cable Block Diagram

Cable Block merupakan satu cara untuk menerangkan hubungkait keseluruhan cable yang terdapat dalam Process Plant.
Ia perlu dihasilkan dengan penuh tanggungjawab bagi memastikan ia dapat difahami dan diterjemahkan dengan mudah oleh setiap orang yang melihatnya.

Ia merupakan pemudah cara untuk menyemak setiap cable yang terdapat dalam sistem kawalan (DCS/IPS/FGS, dsbnya) , antara fakta yg perlu ada ialah:
· Cable Type
· Cable Size
· Originate
· Destination
· Maklumat goegrafi yang jelas

Bagaimana hendak menghasilkan Cable block Diagram:
· Perlu memahami system secara keseluruhan
· Perlu memahami jenis signal yang digunakan
· Perlu tahu jenis cable yang hendak digunakan
· Perlu tahu destinasi signal dan punca signal
· Perlu tahu kedudukkan setiap komponen dengan jelas

THE 4-20mA CURRENT LOOP

THE 4-20mA CURRENT LOOP
The 4-2OmA current loop has been with us for so longthat it's become rather taken for granted in the industrialand process sectors alike. Its popularity comes from itsease of use and its performance. However, just becausesomething is that ubiquitous doesn't mean we're allnecessarily getting the best out of our current loops.
A big benefit of the current loop is its simple wiring justthe two wires. The supply voltage and measuring currentare supplied over the same two wires. Zero offset of thebase current (ie. 4mA) makes cable break detection simple:if the current suddenly drops to zero, you have a cable break.In addition, the current signal is immune to any stray electricalinterference, and a current signal can be transmitted overlong distances.

Typical wiring for current output transducer.
You can think of the current loop itself as being analogousto a water system. You have a hose pipe (the wires) anda source tap (the power supply). You have a spray gunthat regulates the flow (the transducer). You can haveother equipment on the line, but it all has to be connectedtogether in a ring Ioop. The more holes (devices) you haveon the hose pipe, the higher the pressure will be requiredfrom the tap. Relating all that back to the current loop,you see a power supply, a transducer and one or morepieces of instrumentation all connected together in a ring.
You'll often hear things referred to as being either activeor passive. Some instruments have an active output whichincludes both the control of the current in the loop as wellas provide the supply voltage. This is typically specifiedas being a 4-20mA output into 10-750 Ohms, or somethingsimilar. A passive input would be a simple resistor input thathas a voltage drop to be factored into the equation oncethe supply voltage is chosen. This is typically specified asa 4-20mA input into 10 Ohm.
Working out the power supply requirement is a simple matterof adding up all the units in the loop at maximum currentof 20mA. As an example, suppose you have a sensor'regulator' which requires minimum 12V DC and instrumentationof 10 Ohm input:
10 Ohm x 20mA = 0.2V
So, for this circuit, a 12.2V minimum supply is required, thesensor's maximum voltage might be specified at 30V, so a24V supply would be all the circuit requirements with sparecapacity to boot.
In order to measure the current loop it is necessary to breakthe loop and insert a current meter into it. You can alsomeasure the voltage across the various components by inthe loop, such as the voltage out of the power supply, thevoltage over a sensor, and the voltages over the variouspieces of instrumentation. This information will give you agood picture of what is happening within the loop.

Multi-instrument 4-20mA current loop with panel meter,chart recorder, computers, etc.
A question which is sometimes asked is whether it is possibleto use single power supply over several loops. This is possible,but you have to ensure that the power supply can give enoughcurrent to meet the needs of multiple loops. It is also thecase that the current loops will have the same zero negativereference, which can cause a ground loop. In addition,interference from one loop can affect all the other loopsdriven from the one supply.
This article is printed with the kind permission ofMorten Moller, who runs an internet support andconsultancy business and can be contacted atmorten@askmorten.co.ukHis website is at http://www.askmorten.co.uk/

Installation Detail/Hook-up

Installation Detail/Hook-up

Installation Detail atau sketch perlu memaparkan apa yang diperlukan untuk memasang sesuatu instrument.

Ini termasuk kesemua bahan (material) yang yang diperlukan untuk melengkapkan satu proses pemasangan (installation).
Maklumat dari pihak vendor adalah amat perlu bagi memastikan segala bahan yang diperlukan adalah sesuai dan sepadan dengan saiz connection yang diperlukan oleh instrument.

Designer jga perlu mengandaikan situasi dimana Tukang Pasang tidak biasa atau pertama kali memasang Instrument tersebut.

Location Plan/Plot Plan

Location Plan/Plot Plan
Instrument Location plan memasukan semua Instrument yang berhubungkait dengan instrument lain.
Selalunya terbahagi kepada dua fungsi iaitu:
1. Untuk kegunaan pemasangan (Installation) Instrument dan pemasangan tiub untuk Process connection dan tiub untuk signal pneumatik. Ini selalunya melibatkan kerja-kerja paip dan tiub (pipe fitter). Jadi rajah Location Plan dan Tube routing layout perlu dihasilkan.
2. Untuk kegunaan pendawaian. Ini melibatkan kerja-kerja perancangan utk laluan kabel dan lokasi kotak pencawang (JB). Jadi rajah Cable Tray/Ladder perlu dihasilkan untuk panduan pemasangan Cable Ladder/Tray. Manakala rajah Cable Routing pula diperlukan sebagai panduan kerja pendawaian dilakukan dengan cekap.

Rajah dasar (back ground) biasanya diambil dari rajah Piping atau Equipment Layout.

Saiz Helaian-ISO

Saiz helaian mengikut ISO

Saiz Helaian -ANSI

Saiz helaian mengikut ANSI

Wire & Cable Cross reference

BS5308 Cables

---

BS5308 Part 1 / Type 1 Unarmoured Construction

1. Plain annealed copper wire conductors to BS 6360

2. Polyethene insulation to BS 6234

3 Individual pair screen (optional):-
a) Aluminium/polyester tape, metallic side down, in contact with minimum 0.5mm2 tinned copper drain wire
b) Polyester isolating tape(s) numbered for identification

4 Polyester binder tape

5 Collective screen (optional) - Aluminium/polyester tape, metallic side down, in contact with minimum 0.5mm2 tinned copper drain wire

6 PVC sheath to BS 7655

---

BS5308 Part 1 / Type 2 Armoured Construction

1 Plain annealed copper wire conductors to BS 6360

2 Polyethene insulation to BS 6234

3 Individual pair screen (optional):-
a) Aluminium/polyester tape, metallic side down, in contact with minimum 0.5mm2 tinned copper drain wire
b) Polyester isolating tape(s) numbered for identification

4 Polyester binder tape

5 Collective screen (optional) - Aluminium/polyester tape, metallic side down, in contact with minimum 0.5mm2 tinned copper drain wire

6 Black polyethylene bedding to BS 6234

7 Single layer galvanised steel wire armour to BS EN 10257-1

8 PVC sheath to BS 7655

---

BS5308 Part 2 / Type 1 (unarmoured)

1 Plain annealed copper wire conductors to BS 6360

2 PVC to BS 7655

3 Individual pair screen (optional):-
a) Aluminium/polyester tape, metallic side down, in contact with minimum 0.5mm2 tinned copper drain wire
b) Polyester isolating tape(s) numbered for identification

4 Polyester binder tape

5 Collective screen (optional) - Aluminium/polyester tape, metallic side down, in contact with minimum 0.5mm2 tinned copper drain wire

6 PVC sheath to BS 7655

---

BS5308 Part 2 / Type 2 (armoured)

1 Plain annealed copper wire conductors to BS 6360

2 PVC to BS 7655

3 Individual pair screen (optional):-
a) Aluminium/polyester tape, metallic side down, in contact with minimum 0.5mm2 tinned copper drain wire
b) Polyester isolating tape(s) numbered for identification

4 Polyester binder tape

5 Collective screen (optional) - Aluminium/polyester tape, metallic side down, in contact with minimum 0.5mm2 tinned copper drain wire

6 PVC bedding to BS 7655

7 Single layer galvanised steel wire armour to BS EN 10257-1

8 PVC sheath to BS 7655

NEMA Enclosure Types

NEMA PC Enclosure Types

http://www.industrial-computer-enclosure.co.uk/NEMA4.htm

This document provides general information on the definitions of NEMA Enclosure Types
Definitions[From NEMA 250-1997]

In Non-Hazardous Locations, the specific enclosure Types, their applications, and the environmental conditions they are designed to protect against, when completely and properly installed, are as follows:

Type 1 - The unit is constructed for indoor use to provide a degree of protection to personnel against incidental contact with the enclosed equipment and to provide a degree of protection against falling dirt.

Type 2 - Enclosure constructed for indoor use to provide a degree of protection to personnel against incidental contact with the enclosed equipment, to provide a degree of protection against falling dirt, and to provide a degree of protection against dripping and light splashing of liquids.

Type 3 - Pc cabinet constructed for either indoor or outdoor use to provide a degree of protection to personnel against incidental contact with the enclosed equipment; to provide a degree of protection against falling dirt, rain, sleet, snow, and windblown dust; and that will be undamaged by the external formation of ice on the enclosure.

Type 3R - Cabinet constructed for either indoor or outdoor use to provide a degree of protection to personnel against incidental contact with the enclosed equipment; to provide a degree of protection against falling dirt, rain, sleet, and snow; and that will be undamaged by the external formation of ice on the enclosure.

Type 3S - Computer cabinet constructed for either indoor or outdoor use to provide a degree of protection to personnel against incidental contact with the enclosed equipment; to provide a degree of protection against falling dirt, rain, sleet, snow, and windblown dust; and in which the external mechanism(s) remain operable when ice laden.

Type 4 - Computer enclosures constructed for either indoor or outdoor use to provide a degree of protection to personnel against incidental contact with the enclosed equipment; to provide a degree of protection against falling dirt, rain, sleet, snow, windblown dust, splashing water, and hose-directed water; and that will be undamaged by the external formation of ice on the enclosure.

Type 4X - protection unit constructed for either indoor or outdoor use to provide a degree of protection to personnel against incidental contact with the enclosed equipment; to provide a degree of protection against falling dirt, rain, sleet, snow, windblown dust, splashing water, hose-directed water, and corrosion; and that will be undamaged by the external formation of ice on the enclosure.

Type 5 - computer enclosure constructed for indoor use to provide a degree of protection to personnel against incidental contact with the enclosed equipment; to provide a degree of protection against falling dirt; against settling airborne dust, lint, fibres, and flyings; and to provide a degree of protection against dripping and light splashing of liquids.

Type 6 - PC Enclosures constructed for either indoor or outdoor use to provide a degree of protection to personnel against incidental contact with the enclosed equipment; to provide a degree of protection against falling dirt; against hose-directed water and the entry of water during occasional temporary submersion at a limited depth; and that will be undamaged by the external formation of ice on the enclosure.

Type 6P - cabinet constructed for either indoor or outdoor use to provide a degree of protection to personnel against incidental contact with the enclosed equipment; to provide a degree of protection against falling dirt; against hose-directed water and the entry of water during prolonged submersion at a limited depth; and that will be undamaged by the external formation of ice on the enclosure.

Type 12 - computer cabinet constructed (without knockouts) for indoor use to provide a degree of protection to personnel against incidental contact with the enclosed equipment; to provide a degree of protection against falling dirt; against circulating dust, lint, fibres, and flyings; and against dripping and light splashing of liquids.

Type 12K - Enclosures constructed (with knockouts) for indoor use to provide a degree of protection to personnel against incidental contact with the enclosed equipment; to provide a degree of protection against falling dirt; against circulating dust, lint, fibres, and flyings; and against dripping and light splashing of liquids.

Type 13 - Enclosures constructed for indoor use to provide a degree of protection to personnel against incidental contact with the enclosed equipment; to provide a degree of protection against falling dirt; against circulating dust, lint, fibres, and flyings; and against the spraying, splashing, and seepage of water, oil, and non-corrosive coolants.

PC Enclosure Classification Designations

IEC Publication 60529 Classification of Degrees of Protection Provided by Enclosures provides a system for specifying the enclosures of electrical equipment on the basis of the degree of protection provided by the enclosure. IEC 60529 does not specify degrees of protection against mechanical damage of equipment, risk of explosions, or conditions such as moisture (produced for example by condensation), corrosive vapours, fungus, or vermin. The NEMA Standard for Enclosures for Electrical Equipment does test for environmental conditions such as corrosion, rust, icing, oil, and coolants. For this reason, and because the test and evaluations for other characteristics are not identical, the IEC Enclosure Classification Designations cannot be exactly equated with the enclosure Type numbers in this Standard.

The IEC designation consists of the letters IP followed by two numerals. The first characteristic numeral indicates the degree of protection provided by the enclosure with respect to persons and solid foreign objects entering the enclosure. The second characteristic numeral indicates the degree of protection provided by the enclosure with respect to the harmful ingress of water.
Table A-1 provides an equivalent conversion from the enclosure Type numbers in this Standard to the IEC Enclosure Classification Designations. The enclosure type numbers meet or exceed the test requirements for the associated IEC Classification; for this reason Table A-1 cannot be used to convert from IEC Classifications to enclosure Type numbers.
Table A-1 [From NEMA 250-1997]
Conversion of Enclosure Type numbers to IEC Classification Designations
Cannot be used to convert IEC Classification Designations to NEMA Type numbers

Enclosure

NEMA -IEC IP


1 -IP10

2 -IP11

3 -IP54

3R- IP14

3S -IP54

4 and 4X- IP56

5 -IP52

6 AND 6P- IP67

12 AND 12K -IP52

13- IP54

Cable Tray

Cable Tray

A cable tray system, according to the US National Electrical Code, is "a unit or assembly of units or sections and associated fittings forming a rigid structural system used to securely fasten or support cables and raceways." Cable trays are used to hold up and distribute cables.

Types

• Ladder
• Solid Bottom
• Trough
• Channel
• Wire Mesh
• Single Rail

Materials used

• Steel
• Aluminium
• Plastic
• Fibreglass reinforced plastic

The choice of materials is a matter of the physical and mechanical properties produced by each, compared against the intended function, as well as the environment, in which the trays are to be installed.

Introduction to AutoCAD

AutoCAD is a suite of CAD software products for 2- and 3-dimensional design and drafting, developed and sold by Autodesk, Inc.. The original concept of AutoCAD in the 1980s was to promote customization and feature extensibility, and was what made it especially appealing to customers. Most contemporary CAD products at that time offered little if any customization capability and most were far more expensive.

Modern AutoCAD includes a full set of basic solid modeling and 3D tools, but lacks some of the more advanced capabilities of solid modeling applications. AutoCAD can be used as a platform for other products such as Bentley AutoPLANT and COADE CADWORX. AutoCAD is a vector graphics drawing program. It uses primitive entities — such as lines, polylines, circles, arcs, and text — as the foundation for more complex objects.

AutoCAD supports a number of application programming interfaces (APIs) for customization and automation. These include AutoLISP, Visual LISP, VBA, .NET and ObjectARX. ObjectARX is a C++ class library, which was also the base for products extending AutoCAD functionality to specific fields, to create products such as Autodesk Architectural Desktop, AutoCAD Electrical, or third-party AutoCAD-based applications.

AutoCAD's native file format, DWG, and to a lesser extent, its interchange file format, DXF, have become de facto standards for interchange of CAD data. AutoCAD in later years has adopted another file format known as DWF. These files allow selected DWG drawings to be compiled to one file. This allows distribution of the drawings to those without AutoCAD or similar packages. It also protects the drawings from manipulation by others as the drawings are rasterized inside the DWF file. DWF files can be viewed with a free program from Autodesk called "DWF Viewer" - this program allows users to both view and print DWF files. Another advantage of DWF files is that a large number of drawings can be compiled to a single DWF and be of a very small to reasonble file size for electronic distribution. In 2006, Autodesk estimated the number of active DWG files to be in excess of one billion. In the past, Autodesk has estimated the total number of DWG files in existence to be more than three billion.

AutoCAD currently runs exclusively on Microsoft desktop operating systems. Versions for Unix and Macintosh were released in the 1980s and 1990s, but these were later dropped. AutoCAD can run on an emulator or compatibility layer like Virtual PC or Wine, keeping in mind the performance issues that can arise when working with 3-dimensional objects or large drawings. AutoCAD exists in 14 language localizations, including many European and Asian languages.

Introduction to CAD

From Wikipedia, the free encyclopedia

CAD is used to design, develop and optimize products, which can be goods used by end consumers or intermediate goods used in other products.

CAD is also extensively used in the design of tools and machinery used in the manufacture of components, and in the drafting and design of all types of buildings, from small residential types (houses) to the largest commercial and industrial structures (hospitals and factories).

CAD is mainly used for detailed engineering of 3D models and/or 2D drawings of physical components, but it is also used throughout the engineering process from conceptual design and layout of products, through strength and dynamic analysis of assemblies to definition of manufacturing methods of components.

CAD has become an especially important technology, within CAx, with benefits, such as lower product development costs and a greatly shortened design cycle, because CAD enables designers to lay out and develop their work on screen, print it out and save it for future editing, saving a lot of time on their drawings.

CAD is mainly used for detailed engineering of 3D models and/or 2D drawings of physical components, but it is also used throughout the engineering process from conceptual design and layout of products, through strength and dynamic analysis of assemblies to definition of manufacturing methods of components.