Determining Temperature Rise

The temperature rise inside a sealed cabinet without forced ventilation can be approximated as follows. First calculate the surface area of the enclosure and, from the expected heat load and the surface area, determine the heat input power in watts/ft.2   Then the expected temperature rise can be read from the Sealed Enclosure Temperature Rise graph. Find where the input...

Heat Dissipation in sealed electrical enclosures

heaT DissipaTion in sealeD elecTrical enclosures The accumulation of heat in an enclosure is potentially damaging to electrical and electronic devices. Overheating can shorten the life expectancy of costly electrical components or lead to catastrophic failure. enclosure maTerials The following discussion applies to gasketed and unventilated enclosures. Higher temperature rises...

LV Switchgear Functions & Selection

DOWNLOAD : http://www.schneider-electric.com.au/documents/electrical-distribution/en/local/electrical-installation-guide/EIG-H-LV-switchgear.pdf   ...

Low Voltage Motor Control Center Installation Manual

DOWNLOAD :   http://www05.abb.com/global/scot/scot209.nsf/veritydisplay/008793e38b573ad8c12579cf00081a22/$file/2TDA090000P0001_REVB.pdf   ...

Handbook of Electrical Installation Practice

DOWNLOAD : http://www.beknowledge.com/wp-content/uploads/2011/01/c4ca4Electrical_Installation_Practice__Stokes.pdf   ...

Terms AC1 and AC3

AC-1 - This category applies to all AC loads where the power factor is more than 0.95. These are primarily non-inductive or slightly inductive loads, such as heating. Breaking the arc remains easy with minimal arcing and contact wear.   AC-3 - This category applies to squirrel cage motors with breaking during normal running of the motor. On closing, the contactor makes the inrush...

Three-phase Distribution Boards And Socket Circuits (Trade of Electrician Standards Based Apprenticeship)

DOWNLOAD : http://www.ecollege.ie/site/liu/electrical_notes/LL232.pdf   ...

Cross Reference (Approximate) NEMA, UL, CSA, vs. IEC Enclosure Type

  (Cannot be used to convert IEC Classifications to NEMA Type numbers) ...

International Standard Agencies

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Understanding Type 2 Coordinated Protection in Motor Branch Circuits

The new IEC (International Electrotechnical Commission) standard, publication 947 “Low Voltage Switchgear and Control, Part 4-1: Contactors and Motor Starters,” has been recognized by UL (Underwriters Laboratories) and is becoming widely accepted by designers and users of motor control in the U.S. This standard addresses coordination between the branch circuit protective device...

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....

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...