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IEC 61219 Ed. 1.0 b:1993, Live working - Earthing or earthing and short-circuiting equipment using lances as a short-circuiting device - Lance earthing

Applies to equipment for temporary earthing or earthing and short-circuiting of electrically isolated parts of a.c. installations, the disconnection of which has been verified, for the protection of workers while work is in progress using lance(s) as the earthing or earthing and short-circuiting device. Specifies the perfomance and safety requirements and tests for lance devices with matching fixed contacts, guiding arrangements, enclosure, insulating elements and earthing cables, if any. For devices containing short-circuiting cables see IEC 61230.

100118-N-1522S-003
JACKSONVILLE, Fla. (Jan. 18, 2010) Marine Staff Sgt. Jonathon Thompson inspects cargo from the U.S. Agency for International Development (USAID) and the Marine Corps at Blount Island Command, Jacksonville, Fla. before loading it aboard the Military Sealift Command maritime prepositioning ship USNS 1st Lt. Jack Lummus (T-AK-3011). USAID provided more than 74 pallets of relief supplies. The Marine Corps cargo included vehicles and heavy equipment to support the distribution of supplies, water production, water distribution and fuel distribution. The Marines also provided limited earth-moving equipment, electrical-producing equipment, limited lumber, building materials, and medical supplies. The ship and supplies are bound for Haiti as part of Operation Unified Response providing humanitarian assistance and disaster relief in the aftermath of a 7.0 magnitude earthquake on Jan. 12, 2010. (U.S. Navy photo by Mass Communication Specialist 1st Class Leah Stiles/Released)

Gas-discharge protectors were small enough to fit inside your master telephone socket, your line would have been protected by a lightning-arrestor like this.

The incoming lines are taken to the internal telephone wiring via a 2.5A fuse in each leg, with a moulded spark-gap protector (type 'Protector No:1A') between each leg and earth. 'Protector No:1A' consists of two brass electrodes separated by a perforated insulated film, designed to break down at 750V (± 150V).

The unit is pleasingly encased in a bakelite box 4" x 1 ?" x 1? "

A step-by-step guide to solving noise and interference problems in the digital age

The rapid growth of digital technology over the past decade has brought the analog world into direct contact with high-speed operations and electromagnetic processes--and created a host of new problems for designers. This new twist requires different approaches to issues of noise and interference in digital processing, high-speed communication, mass data storage, and high-frequency applications.

Grounding and Shielding Techniques, Fourth Edition is entirely rewritten to reflect these new challenges. This highly effective tool for the management of interference problems in electronic equipment treats the fundamentals of electrostatics as they relate to electromagnetic phenomena. Specifically, this volume deals with the new interference problems created when analog designs are buried in the middle of hardware that must meet radiation and susceptibility standards. It features:
* Effective techniques for handling noise problems in a variety of circumstances
* Step-by-step instructions for building noise-free instrument systems
* Strategies for reducing or eliminating noise in interconnecting systems
* Expanded discussion of multishielded transformers
* An overview of current trends to limit the use of transformers
* Real-world examples of factors influencing electronic noise
* Simplified, practical explanations of the physics of fields
* Dozens of illustrations and a clear, readable text.

Grounding and Shielding Techniques, Fourth Edition is a state-of-the-art problem-solving guide for electronic design engineers and technicians. It is also an extremely useful text for short courses on electronic noise.