Letters: Reader Feedback

Power for security In the article “Quality Power for Security Systems” (Pure Power, Fall 2007, p. 17) the author gives “underground local metal structures (gas piping, for example)” as one of the legal ways of connecting a grounding system to the earth. The author refers to the National Electrical Code for the listing.

11/01/2007


Power for security

In the article “Quality Power for Security Systems” (Pure Power, Fall 2007, p. 17) the author gives “underground local metal structures (gas piping, for example)” as one of the legal ways of connecting a grounding system to the earth. The author refers to the National Electrical Code for the listing. But according to NEC Article 250-52(a), “a metal underground gas piping shall not be used as a grounding electrode.” Can the author expand on this?

Igor A. Altshuler Engineer Baltimore via the internet

Author responds:

Indeed, you are most correct. The statement should have read “Other local metal underground piping (except gas lines).” Likewise, tanks that have been used to store explosive or hazardous contents should not be used as supplemental grounding electrodes. An acceptable example would be an abandoned underground metallic water storage tank that has been filled with moist sand.

Jay Adams Applications Engineer Transtector Systems Shayden, Idaho

Energy efficiency

The story “The climate has changed for energy efficiency” ( www.csemag.com , 10/22/07) said that “the energy used by commercial and industrial buildings in the United States is responsible for 45% of the nation's greenhouse gas emissions.” This is encouraging for the potential to make a big dent in those emissions. Although most domestic and non-domestic buildings are very wasteful of energy, in many ways that waste is easier to tackle in non-domestic buildings: First, the energy bill is usually much higher in non-domestic buildings, so there are greater financial rewards to be achieved by investing time into improving energy efficiency. There's a big economy-of-scale effect in the savings that can be achieved by investing time into energy management.

Second, the larger the building, the greater the chance that it already has interval metering equipment and access to interval energy data from that equipment. For buildings that don't have such equipment, the larger they are, the greater the payback from investing in such equipment. Analysis of such interval energy data for energy management purposes can easily lead to identification of huge sources of energy waste that would be very difficult to find without that data. Admittedly, these benefits will spread into the domestic sector as interval metering catches on there. Ultimately, the greatest energy saving are from motivating people to do their bit. This can be difficult in a work or home environment, but initiatives such as the Kilowatt Crackdown can make a huge difference.

Martin Bromley Energy Management Consultant via the internet





No comments
The Engineers' Choice Awards highlight some of the best new control, instrumentation and automation products as chosen by...
The System Integrator Giants program lists the top 100 system integrators among companies listed in CFE Media's Global System Integrator Database.
The Engineering Leaders Under 40 program identifies and gives recognition to young engineers who...
This eGuide illustrates solutions, applications and benefits of machine vision systems.
Learn how to increase device reliability in harsh environments and decrease unplanned system downtime.
This eGuide contains a series of articles and videos that considers theoretical and practical; immediate needs and a look into the future.
System integration: Best practices and technologies to help; Virtualization virtues; Cyber security advice; Motor system efficiency, savings; Product exclusives; Road to Hannover
Collaborative robotics: How to improve safety, return on investment; Industrial Internet of Things, Industrie 4.0: World views; High-performance HMI, Information Integration: OPC and OMG
9 tips: How to integrate a servo system; Process control mathematical models; Serial network grounding; Engineers' Choice Awards; Learn from cyber security mistakes
This article collection contains several articles on the Industrial Internet of Things (IIoT) and how it is transforming manufacturing.
PLCs, robots, and the quest for a single controller; how OEE is key to automation solutions.
Learn how Industry 4.0 adds supply chain efficiency, optimizes pricing, improves quality, and more.

Find and connect with the most suitable service provider for your unique application. Start searching the Global System Integrator Database Now!

Getting to the bottom of subsea repairs: Older pipelines need more attention, and operators need a repair strategy; OTC preview; Offshore production difficult - and crucial
Digital oilfields: Integrated HMI/SCADA systems enable smarter data acquisition; Real-world impact of simulation; Electric actuator technology prospers in production fields
Special report: U.S. natural gas; LNG transport technologies evolve to meet market demand; Understanding new methane regulations; Predictive maintenance for gas pipeline compressors
click me