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A Safety Measure Taken for Granted

Tuesday, 25 November 2008 22:27

There is a saying that "experience is the worst teacher, test comes first before the lesson".

This is true in every aspect. In electrical engineering design, earthing or grounding is almost always the least concern of designers and installers. It is a safety measure mostly taken for granted as the benefits of earthing or grounding are not realized until the occurrence of a fault in the system. The importance of earthing is only known when an earth fault happens, however the occurrence of a fault may only be a split of a second as the protection system has already cleared out the fault.

Do not let the test comes first, do not let an accident happens before you learn your lesson. Always make sure that in every aspect of electrical design, earthing or grounding is taken into consideration.

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Metal-Clad vs Metal-Enclosed

Tuesday, 04 November 2008 04:47

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The selection of the type of switchgear to be used in a project is a tedious job. Design engineers need to know what are the requirements of the project to be able to specify what type of switchgear is needed. In a project with a highly skilled personnel and requires monitoring, a metal-clad switchgear is recommended.

Metal-Clad vs Metal-Enclosed
	Metal-clad	Metal-enclosed
Main Interrupting Device	Drawout circuit breakers	Fixed Switch and fuse combination
Bus works	Insulated	Bare
Live Parts	No exposed live parts even when cover is removed	Exposed live parts when cover is removed
Cost	High	Low
Maintenance	High	Low
Auxiliary Power	Yes	No
Single Phasing Protection	Standard	Options
Communication Interface	Available	None

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Hign Voltage Switchgear Rated Insulation Level

Monday, 03 November 2008 05:07

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The Common specifications for high-voltage switchgear and controlgear standards ( IEC 60694:2002 ) tables 1 and 2 provide the rated insulation levels of switchgears and controlgears. In these tables, the withstand voltage applies at the standardized reference atmosphere (temperature, pressure and humidity) specified in IEC 60071-1.

The rated withstand voltage values for lightning impulse voltage (Up), switching impulse voltage (Us) (when applicable), and power-frequency voltage (Ud) shall be selected without crossing the horizontal marked lines. The rated insulation level is specified by the rated lightning impulse withstand voltage phase to earth.

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We need your suggestions

Tuesday, 28 October 2008 21:38

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We have completed our first year online and we more than 230 members, and almost 20k hits. We consider this as a good accomplishment on our part but we wanted to listen to whatever our visitors want for us to be able to provide a better service.

By means of this post, we wanted to solicit your ideas to make this The Filipino Engineer better.

Thank you very much - TFE Admin Team

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Anniversary Challenge

Thursday, 09 October 2008 00:13

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We will be celebrating its 1 year anniversary on the 24th of October 2008.

To make the celebration more enjoyable, we are giving away "Free Webhosting and Domain name" (courtesy of our sponsor) for a year to our member who are able to provide the first correct answer to our challenge question.

The Challenge:
The photos are taken from the cable compartment of an 11KV Switchgear. The installation may be acceptable to a trade person or the installer. However, put yourself into the shoes of an Electrical Inspector or the Design Engneer. Spot installation errors which make the installation unacceptable or requiring rework.

11kV Switchgear Photo A