Why Are Copper Bus Bars Plated?

Even though copper is the most popular choice for use in bus bars, and used very often in other electrical applications because it is more resistant to rust and corrosion than other metals, this doesn’t mean that it won’t oxidize over time.

 

When metals oxidize, the resistance in the conductive metal will increase, requiring more power to be used to carry current along the surface. When the copper oxidizes beyond a certain point, the metal can begin to flake and fall apart.

 

Many metals are plated in order to help them retain their positive qualities and attributes. When it comes to copper bus bars, plating is an important factor in longevity as well as maintaining the integrity of the conductive surface. When copper bus bars are not plated, over time the surface will oxidize. When that occurs, then more power is required to push electricity along the surface because the oxidized surface simply doesn’t conduct as well as a smooth, plated surface.

 

Plating, using tin or silver acts as a coating over the surface of the copper, helps to protect the copper from oxidizing. While this will not completely prevent oxidizing over a long period of time, it will dramatically reduce the effects of such oxidization. The reason why tin and silver is commonly used in the plating technique for copper is that both metals are considered soft metals, easier to work with when plating, and more importantly they don’t offer a great deal of resistance to electrical conductivity.

 

Which is better? Tin or Silver?

 

Throughout the industry there are different thoughts about which metal is better for plating copper, tin or silver. 10 microns of tin will outperform 1 micron of silver. With the price of silver climbing, tin becomes more economical, even though ten times the amount of tin will be required to do the same job.

 

When using silver to plate copper bus bars, a minimum of 3 microns should be used, and preferable 6 microns. On top of that, an anti-tarnish would need to be applied as well to protect the finish. In most fixed bus bar applications, tin is recommended. Silver should be used for moving bus bar parts in which arcing may be a concern.

 

For both tin and silver plating, anti-tarnish is important to keep the surface clean and conductive. When working with copper bus bars, plating is essential not only for longevity, but also integrity and safety.

 

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CE marking

 

The CE marking indicates a product’s compliance with EU legislation and so enables the free movement of products within the European market. By affixing the CE marking to a product, a manufacturer declares, on his sole responsibility, that the product meets all the legal requirements for the CE marking, which means that the product can be sold throughout the European Economic Area (EEA, the 28 Member States of the EU and European Free Trade Association (EFTA) countries Iceland, Norway, Liechtenstein). This also applies to products made in other countries which are sold in the EEA.

 

However, not all products must bear the CE marking, only product categories mentioned in specific EU directives on the CE marking.

 

CE marking does not indicate that a product was made in the EEA, but merely states that the product has been assessed before being placed on the market and thus satisfies the applicable legislative requirements (e.g. a harmonized level of safety) enabling it to be sold there. It means that the manufacturer has:

 

verified that the product complies with all relevant essential requirements (e.g. health and safety or environmental requirements) laid down in the applicable directive(s) and

if stipulated in the directive(s), had it examined by an independent conformity assessment body.

It is the manufacturer’s responsibility to carry out the conformity assessment, to set up the technical file, to issue the declaration of conformity and to affix the CE marking to a product. Distributors must check that the product bears the CE marking and that the requisite supporting documentation is in order. If the product is being imported from outside the EEA, the importer has to verify that the manufacturer has undertaken the necessary steps and that the documentation is available upon request.

 

Copyright CE-Marking

IEC 60364 Electrical Installations for Buildings

IEC 60364 Electrical Installations for Buildings is the International Electro technical Commission's international standard on electrical installations of buildings. This standard is an attempt to harmonize national wiring standards in an IEC standard. The latest versions of many European wiring regulations (e.g., BS 7671 in the UK) follow the section structure of IEC 60364 very closely, but contain additional language to cater for historic national practice and to simplify field use and determination of compliance by electrical tradesmen and inspectors. National codes and site guides are meant to attain the common objectives of IEC 60364, and provide rules in a form that allows for guidance of persons installing and inspecting electrical systems.

The standard has several parts:

 

Part 1: Fundamental principles, assessment of general characteristics, definitions

Part 4: Protection for safety

Section 41: Protection against electric shock

Section 42: Protection against thermal effects

Section 43: Protection against overcurrent

Section 44: Protection against voltage disturbances and electromagnetic disturbances

Part 5: Selection and erection of electrical equipment

Section 51: Common rules

Section 52: Wiring systems

Section 53: Isolation, switching and control

Section 54: Earthing arrangements, protective conductors and protective bonding conductors

Section 55: Other equipment

Section 56: Safety services

Part 6: Verification

Part 7: Requirements for special installations or locations

Section 701: Electrical installations in bathrooms

Section 702: Swimming pools and other basins

Section 703: Rooms and cabins containing sauna heaters

Section 704: Construction and demolition site installations

Section 705: Electrical installations of agricultural and horticultural premises

Section 706: Restrictive conductive locations

Section 708: Electrical installations in caravan parks and caravans

Section 709: Marinas and pleasure craft

Section 710: Medical locations

Section 712: Solar photovoltaic (PV) power supply systems

Section 713: Furniture

Section 714: External lighting

Section 715: Extra-low-voltage lighting installations

Section 717: Mobile or transportable units

Section 740: Temporary electrical installations for structures, amusement devices and booths at fairgrounds, amusement parks and circuses

 

Wikipedia

Welding standards (ISO)

International Organization for Standardization (ISO) has developed over 18500 standards and over 1100 new standards are published every year. The following is a partial list of the standards specific to welding:

Standard Number            Description

ISO 2553               Welded, brazed and soldered joints - symbolic representation on drawings (1992)

ISO 2560               Welding consumables. Covered electrodes for manual metal arc welding of non-alloy and fine grain steels. Classification

ISO 3580               Covered electrodes for manual arc welding of creep-resisting steels - Code of symbols for identification

ISO 3581               Covered electrodes for manual arc welding of stainless and other similar high alloy steels - Code of symbols for identification

ISO 3834               Quality requirements for fusion welding of metallic materials, five parts.

ISO 4063               Welding and allied processes - Nomenclature of processes and reference numbers

ISO 5817               Welding. Fusion-welded joints in steel, nickel, titanium and their alloys (beam welding excluded). Quality levels for imperfections

ISO 6520-1           Welding and allied processes — Classification of geometric imperfections in metallic materials — Part 1: Fusion welding

ISO 6520-2           Welding and allied processes — Classification of geometric imperfections in metallic materials — Part 2: Welding with pressure

ISO 6947               Welds. Working positions. Definitions of angles of slope and rotation

ISO 9606               Qualification test of welders — Fusion welding, parts 1 to 5

ISO 9692-1           Welding and allied processes. Recommendations for joint preparation. Manual metal-arc welding, gas-shielded metal-arc welding, gas welding, TIG welding and beam welding of steels

ISO 9692-2           Welding and allied processes. Joint preparation. Submerged arc welding of steels

ISO 9692-3           Welding and allied processes. Joint preparation. Part 3: TIG and MIG welding of aluminium and its alloys

ISO 13847            Petroleum and natural gas industries - Pipeline transportation systems - Welding of pipelines

ISO 13916            Welding - Guidance on the measurement of preheating temperature, interpass temperature and preheat mainteanance temperature

ISO 13918            Welding - Studs and ceramic ferrules for arc stud welding

ISO 13919-1        Welding - Electron and laser-beam welded joints - Guidance on quality level for imperfections - Part 1: Steel

ISO 13919-2        Welding - Electron and laser-beam welded joints - Guidance on quality level for imperfections - Part 2: Aluminium and its weldable alloys

ISO 13920            Welding - General tolerances for welded constructions - Dimensions for lengths and angles - Shape and position

ISO 14112            Gas welding equipment - Small kits for gas brazing and welding

ISO 14175            Welding consumables — Gases and gas mixtures for fusion welding and allied processes. Replaced EN 439:1994 in Europe.

ISO 14341            Welding consumables. Wire electrodes and deposits for gas shielded metal arc welding of non alloy and fine grain steels. Classification

ISO 14554            Resistance welding

ISO 14744            Electron beam welding, six parts

ISO 15607            Specification and qualification of welding procedures for metallic materials - General rules

ISO/TR 15608     Welding - Guidelines for a metallic material grouping system

ISO 15609            Specification and qualification of welding procedures for metallic materials - Welding procedure specification, five parts.

ISO 15610            Specification and qualification of welding procedures for metallic materials — Qualification based on tested welding consumables

ISO 15611            Specification and qualification of welding procedures for metallic materials — Qualification based on previous welding experience

ISO 15612            Specification and qualification of welding procedures for metallic materials — Qualification by adoption of a standard welding procedure

ISO 15613            Specification and qualification of welding procedures for metallic materials — Qualification based on pre-production welding test

ISO 15614            Specification and qualification of welding procedures for metallic materials - Welding procedure test, 13 parts.

ISO 15615            Gas welding equipment. Acetylene manifold systems for welding, cutting and allied processes. Safety requirements in high-pressure devices

ISO 15618-1        Qualification testing of welders for under-water welding. Diver-welders for hyperbaric wet welding

ISO 15618-2        Qualification testing of welders for under-water welding. Diver-welders and welding operators for hyperbaric dry welding

ISO 17635            Non-destructive testing of welds. General rules for metallic materials

ISO/TR 20172     Welding — Grouping systems for materials — European materials

ISO/TR 20173     Welding — Grouping systems for materials — American materials

ISO/TR 20174     Welding — Grouping systems for materials — Japanese materials

ISO 24394            Welding for aerospace applications. Qualification test for welders and welding operators. Fusion welding of metallic components

Regulations for the Installation of Electrical Wiring, Electrical Equipment and Air Conditioning Equipment (Qatar General Electricity & Water Corporation "KAHRAMAA")

 

 

DOWNLOAD :

http://www.km.com.qa/sitecollectiondocuments/service%20regulations/en/regulationsfortheinstallationofelectricalwiringele.pdf

Type of standards (IEC/NEC) for low voltage electrical installations.

 

Electronic starters and variable speed drives Schneider-electric Cahier technique no. 208

DOWNLOAD :

http://www2.schneider-electric.com/documents/technical-publications/en/shared/automation/automation-information-networks/ect208.pdf

ABB Guide to variable speed drives

DOWNLOAD :

http://www05.abb.com/global/scot/scot201.nsf/veritydisplay/d3c711ec2acddb18c125788f002cf5da/$file/ABB_Technical_guide_No_4_REVC.pdf

 

Electrical Switchboard Routine Tests

Physical Check

·         Visual check for any physical damages on the enclosures, paint removal and breakage on components

·         Paint shade as per the approved drawings.

·         Cable feeding provisions

·         General layout of the panel.

·         Check whether all the components are fitted.

·         Check for the Labels and nomenclature

·         Size of Bus bars

Dimensional Check

·         Over all dimensions with approved drawings.

·         List of components its layouts

·         Labels descriptions

Wiring and Control Circuit Check

·         Instrument panel wiring.

·         Control circuit wiring.

·         Power wiring.

·         Protective circuits

·         Rating of breakers

·         Rated voltage of all components

·         Rating of Fuses

Mechanical Operations

·         ON/OFF operations of the circuit breakers by manually.

·         Draw out operations of the withdrawable breakers

·         Breaker interlocking mechanism

·         Electronic protection device of the breakers

·         Operations of the control components like control switches, limit switches etc.

·         Operations of the door interlocking mechanism.

Electrical Operations

·         Electrical ON/OFF operations of the circuit breakers.

·         Electrical functioning of Starters.

·         Operations of components, contactors, control relays, push buttons, indications lamps etc.

·         Checking of electrical interlocking and sequences.

·         Checking of instruments

·         Checking additional protection relays as Ground Fault & Earth Leakage

Torque Test

·         Check all joints of electrical current carrying parts to ensure the tightness by torque range

·         Bus bar joints

·         Breaker terminals

Insulation Resistance Test

·         To check the protective measure of the insulation value

·         To check the continuity of the circuits.

Dielectric Test

Dielectric Test is conducted as per IEC on the power circuits (excluding controls, instruments and electronic components etc.) The test voltage 2.5KV is applied for a period of 1 min. in between

·         1. Phase and phase

·         2. Phase and neutral

·         3. Phase, neutral and earth

 

Electrical Testing of Low Voltage Switchgear, Panelboards & Switchboards (PEARL)

This "How To" electrical testing document is based on PEARL Reconditioning Standard Section 1300, Revision 5 Low Voltage Panelboards, Switchboards & Switchgear, and discusses relevant test equipment as well as suggested procedures and practices to ensure the quality, safety, and speed of your test-for-reconditioning practices.

Introduction:
The section of the PEARL Reconditioning standards covers the following several low-voltage devices including circuit breaker panelboards, switchboards and switchgear, and motor control centers. Although these devices are different in function, the inspection, reconditioning, and testing of all of these devices have enough in common that PEARL believes in appropriate to group them together under section 1300.

Test Equipment:
The following test equipment is required to perform the testing portion PEARL standards related to low voltage circuit breakers:

1. Insulation Resistance Test Set (Megohmeter) 1000 Vdc minimum
2. High Current Test Set

One of the following pieces of test equipment may be required to perform the testing requirements of this reconditioning standard:

1. AC Voltage Supply
2. AC Current Supply
3. AC 3-Phase Voltage Supply
4. DC Voltage Supply
5. Digital Low Resistance Ohmmeter (DLRO - 10 amp unit is sufficient.)
6. DC Current Source and a Millivoltmeter

Test Reference Tables:
To adequately test the electrical properties of the switchgear, panelboards or switchboards, you will also need the following technical reference documents, which can be found in the PEARL Reconditioning Standards:

1. US Standard bus connection bolt torque values (PEARL Reconditioning Standard 6001, Table 1)
2. Insulation resistance and test values for electrical apparatus (PEARL Reconditioning Standard 6002, Table 2)
3. Insulation resistance and test temperature conversion to 20°C value (PEARL Reconditioning Standard 6011, Table 11)

Testing TIPS:

• Panelboards are tested very much like a disconnect switches are tested, including the test of resistance along current carrying path.
• It is very that the insulation between the current carriers and enclosure is solid and that nothing is escaping to a ground outside the carrying path.
• Don't trust visual inspection as the sole inspection of insulation; a shaving, or crack in a fiberglass or epoxy insulator that is hidden from view can result in a short circuit and leave users exposed to danger.
• Occasionally, new replacement insulators can have hidden cracks, resulting in hours of troubleshooting of a completed panelboard or switchgear. It is prudent to test replacement insulators before installation.
• For motor controls, test each component and subassembly, including transformers, circuit breakers, magnetic contactors, and starters, which can also include integral overload devices that require testing.

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Electrical Safety Testing Reference Guide

DOWNLOAD :

 

http://www.psma.com/ul_files/forums/safety/estguide2.pdf

 

Electrical installation handbook (v2) Electrical devices

 

DOWNLOAD :

 

http://dl.irpdf.com/ebooks/Part10/www.irpdf.com(4491).pdf