Skip navigation

Power distribution

Power distribution technology is creating specialized products for specialized applications, and many of these products are automated for energy management or ease of configuration.If opto-isolators aren't on your hot list of high-voltage equipment to include in your design, it's time for a second look. A new compact, low-cost, high-voltage isolator uses the latest opto-coupler technology to bring

Power distribution technology is creating specialized products for specialized applications, and many of these products are automated for energy management or ease of configuration.

If opto-isolators aren't on your hot list of high-voltage equipment to include in your design, it's time for a second look. A new compact, low-cost, high-voltage isolator uses the latest opto-coupler technology to bring you maximum high-voltage isolation in combination with high frequency response and optimum accuracy. We're talking about 4000VAC rms isolation with up to 35 kHz frequency response at 0.1% full scale accuracy. This is beyond the capabilities of all previous opto-isolator designs. This latest generation has been tested to 5300VAC, and its 2 megohm input resistor can continuously sustain a 1500VDC over-voltage surge for up to a full minute. This opto-isolator protects meters, computers, SCADA systems, and other equipment from being damaged by voltage overloads.

What's new in panelboards? Integral surge suppression, that's what. It makes good sense to have surge suppression right at the service entrance or main distribution panels. However, retrofitting existing panels and switchboards to include surge suppression isn't always an easy thing to do. That's why manufacturers have put a lot of thought into surge protection and have introduced integrated boards and panels. One such panel, for example, has the surge unit mounted directly on the busbar - no leads to consider whatsoever. With active hybrid filtering, it filters to 55dB at 100 kHz, effectively removing such disturbances as high and low energy ringing transients.

Residential power distribution refuses to be left behind in this age of innovation. For example, consider one manufacturer's residential load center. The latest model has an extra 2-in. knockout for wire bundling; adjustable trim for flush leveling; increased wiring gutter space; a large variety of concentric knockouts at the top, bottom, rear, and sides; drywall markings on the sides; and predrilled mounting holes. The manufacturer even ships the cover in a protective cardboard wrapper. The whole focus is on helping the installer do a fast, professional job.

Now available is advanced power distribution monitoring for residential applications. One system, for example, has peak, instantaneous, and accumulated demand metering; a manually or remotely reset non-volatile display; a percent load meter; interface capability for energy management systems; and compatibility with plug-and-play products (appliances, TV's, VCR's stereos, security systems, thermostats, lights, switches, HVAC, etc.) of various manufacture.

Optical metering of transmission currents solves many problems. Optical meters have wide sensing ranges, no requirements for oil or gas insulation systems, no mechanical parts, total isolation from surges, no magnetic core ferroresonance, and no saturation limits. They are significantly smaller than their predecessors. Perhaps that's why one manufacturer introduced optical meters with just these capabilities. A transducer (suitable for outdoors) uses light to accurately measure current on high-voltage systems. One sensor is accurate from less than 5A up to 4000A. The system provides a low energy analog voltage output proportional to the current flowing through the sensor.

Category Two


These items have appeared over the past year in EC&M's Product News section and received the highest reader response in their category.

Nonfused disconnect switches

This new line of compact enclosed nonfused disconnect switches, 30A and 60A versions, catalog symbol BDNF, is used in manual ON and OFF control of single- or 3-phase AC motors. They have standard or optional (field-installed) auxiliary contacts rated 6A at 250V, and they can signal PLCs.

Bussmann/Cooper Industries

Nonmetallic compact disconnect switches

The NRS nonmetallic compact disconnect switches provide manual ON and OFF control of single- and 3-phase AC motors. Offered in a 30A fused and 30A and 60A unfused version, the product meets NEC requirements for a separate disconnect means within sight of all motor loads. The operating handles can be locked in the OFF position to meet OSHA lockout/tagout regulations.

Crouse-Hinds/Cooper Industries

Enhanced loadcenters

The enhanced version of the Type CH premium loadcenter features an all copper bus and a high series-rated single-phase 200A main breaker. Uses high-quality materials, is easy to install, and is manufactured to ensure consistent product quality. Also features more wiring room making the installation faster and easier and allows space for special wiring needs.


Controller panelboard

This panelboard offers a controllable breaker system for use on 120V and 277V, 20A circuits. It incorporates a networkable, microprocessor-based controller and communicates over a twisted pair. The controller and breakers work together to switch branch circuits for lighting and small power without a computer to run the system.


Automatic transfer switches

Representing a major advance in automatic transfer switching technology, a new 1000A to 2000A line of Automatic Transfer Switches for critical power applications is offered. The design allows for field conversion to open, closed, or delayed transition transfer modes of operation, and also offers higher withstand current and extended short time ratings for optimum circuit breaker coordination. Also, the new ASCO SSTS (Solid-State Transfer Switch) is designed to assure the uninterrupted transfer of power between two AC power sources in critical load applications; and the new PULSAR line of high-performance surge protection devices, rated from 40kA to 400kA, provides facility-wide protection.

Automatic Switch

Remote power switching system

The POWERLINK remote power switching system has been enhanced with a firmware download kit. The new capability helps users stay technologically current by providing the ability to install upgraded features into an existing POWERLINK panelboard. The system eliminates the need for separate relay or contactor panels to control loads. Motor-operated circuit breakers are used to switch individual branch circuits.

Square D

Category Two


Manual disconnect switches

This line of 30A and 60A manual disconnect switches is available in nonfused and fused (30A only) models. The non-fused switches combine a 120V- to 600V-hp-rated switch in a durable, watertight enclosure rated NEMA 3R, 4X, 12 for reliable performance in outdoor, washdown, corrosive, and dusty applications. The nonfused and fused manual disconnects are UL 508 and CSA C22.2 No. 14-M91 certified.

Arrow Hart

Current transformers

The Enercept KT directly accepts 208 to 480VAC without a costly potential transformer and can accommodate up to 2400A. Can produce 4-20mA output for instantaneous kW demand or pulses for kWH consumption. The 3-phase mode automatically scales output for balanced loads. Combines a kilowatt transducer with a split-core current transformer in a single compact power sensor. Since the transformer and transducer are mated and tuned, the Enercept KT boasts [+ or -]2.0% accuracy.

Veris Industries

Current transformer

The Model No. HACT-1/10 is a jumbo current clamp capable of encircling busbars measuring approximately 5 x 1 1/4 in. and cables up to 2 3/4 in. dia. This clamp can handle up to 3000A with [+ or -]1% accuracy over its entire range down to 5A. The output is 0.1 mV per amp, and it conforms to IEC 348.

Amprobe Instrument

Medium-voltage switchgear

SafeGear, the new arc-resistant medium-voltage (5 to 15kV) switchgear, is available in the full range of ANSI preferred ratings through 15kV and 1000MVA. Features both 1-high and 2-high (stacked breaker) configurations for maximum economy of floor space. The product is also available with advanced protection and control technologies, including a 3-phase multifunction protection and metering device.

ABB Power T&D

Current transducers

Model HACT-100/1 is a miniature current clamp with resolution down to 50mA, suitable for measuring the current on CT secondaries. Also, its small size enables placement in tight locations. Capable of up to 10A, its output is 100mV per amp. Conforms to IEC 348.

Amprobe Instrument

Transfer switches

This new line of solid state transfer switches (SSTS) utilizes fast, solid-state switching devices to provide virtually uninterrupted transfers of sensitive loads between two AC power sources. Features fast, 1/4-cycle maximum, break-before-make, automatic transfers between two independent AC power sources, even under power system fault conditions.

Automatic Switch

Enhanced switchboard

The AV3 Access, with maximum 5000A main and 1200A feeder breakers, complements existing AV3 switchboard with the added capability of using 100% rated, individually mounted Spectra rms circuit breakers, resulting in cost savings because users can specify these compact breakers instead of using larger frame sizes. There is a 30-cycle withstand, short-circuit tested bus that is designed for up to 85kA, offering improved system coordination.

GE Electrical Distribution & Control

DC watt-hour meter

This versatile watt-hour meter simultaneously views volts, amps, watts, and watt-hours while an optional external counter provides DC watt-hour readings. Model WM accurately measures DC bus power while automatically calculating energy consumption. May be used to drive an optional external electromechanical counter for watt-hour readouts or other remote equipment.

LEM DynAmp

Automatic transfer switches

This new line of automatic transfer switches is designed to provide synchronized power transfer without interruption between a utility and an in-house engine generator. The 956 SLTS (Soft Loading Transfer System) provides a Make-Before-Break transfer of a building's load from a utility to an in-house engine generator. This system brings the engine generator into synchronism with the utility source, then gradually shifts the load over to the engine generator with virtually no voltage or frequency fluctuations, thereby assuring a "seamless" transfer of critical loads.

Automatic Switch

Knife disconnect block

New Knife Disconnect Block for the Din Rail mounted Series No. 280 incorporates the most popular features required for circuit testing. The color knife switch provides a clear indication as to whether it is opened or closed and fully disconnects before allowing access to the blades to ensure a touchproof device.


Electric meter

The 2-phase, 3-wire Transmeter-12 is an electric meter with spread-spectrum power line carrier for automatic meter reading. It communicates over existing distribution wires, eliminating the need for additional wiring. Its PLC automatically bypasses interference by adapting frequency, modulation, and baud rates.

Quadlogic Controls

High-speed source-transfer switching system

The system maintains power to all equipment served by the medium-voltage distribution system. Such continuity of service is crucial for continuous-process industries, where even momentary voltage fluctuations can ca use major disruption and financial loss. The system transfers between preferred and alternate power sources in 4 ms to 8 ms.

S&C Electric

Easy-to-install switch

The Sentron HCP Switch has a compact design and is available in a range from 1200A down to 400A. The high contact pressure unit is available as an F2 panelboard main or as a branch or main in a new switchboard lineup. It can be installed anywhere in a cabinet (top, middle, or bottom), wherever it is needed. Provides circuit breaker-style, butt-type contacts for a secure, solid electrical connection.

Siemens Energy & Automation

Transfer switch control panel

The MX200 microprocessor-based control panel is available for this manufacturer's line of ZTS automatic transfer switches. These control panels monitor line voltages and control the operation and display of the ATS. As an embedded digital controller, device offers high reliability and ease of unattended operation across various applications.

Zenith Controls

Disconnect switches

A new 600A variable depth flange mounted disconnect switch, Bulletin 1494V, has the same footprint and mounting location as its 400A counterpart, allowing for easy upgrading and installation. Incorporates a quick-make, quick-break, snap-action design with a visible blade construction. Available in a fusible or nonfusible version and accepts Class H, J, or R fuses. The switch is UL-listed and CSA-certified.


Transfer switches with UL rating

This series of 5kV 400A and 600A contactor-type automatic transfer switches is labeled and listed under UL Standard 1008. The high-speed, electromagnetically actuated contactor assembly is sealed in an epoxy resin enclosure that provides high strength, resistance to electromagnetic stress, and superior dielectric strength. All operation functions are controlled by a programmable control system that uses industry standard open architecture communication protocol for high-speed serial communications.


Transfer switch with bypass/isolation

A new combination subcycle static transfer bypass/isolation switch, Model RSTS, completes an open transition (break before make) transfer of the load to the alternate (standby) source in 2.4 ms: well below the Computer Business Equipment Manufacturers Association power interruption guideline of 8.3 ms. Also provides a convenient means for manually bypassing and isolating the static switch for maintenance.



The new NF Panelboard is field-convertible from main lug to main circuit breaker and from top to bottom feed. It can be configured to include a split bus with an in-line lighting contactor or two split buses. Field installable options include sub-feed lugs, sub-feed breakers, and feed-through lugs. Optional 200% neutral loading through 600A accommodates nonlinear loads and reduces negative harmonics.

Square D

Digital power meter

The new 7300 ION digital 3-phase power meter features more than 100 revenue-accurate measurements. Measures volts, amps, power, energy, demand, min/max, and more. Compact size, simple installation, and high reliability make it ideal for panel-boards, switchboards, switchgear, gensets, or energy management networks.

Power Measurement

Hide comments


  • Allowed HTML tags: <em> <strong> <blockquote> <br> <p>

Plain text

  • No HTML tags allowed.
  • Web page addresses and e-mail addresses turn into links automatically.
  • Lines and paragraphs break automatically.