Electical Contractor

| May 2004

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Your Business

A different kind of harmony The Stevie Wonder/Paul McCartney classic “Ebony and Ivory” asked why we can’t live together in harmony.

Blinking Light

Surge Protection: Fact or Fiction?

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Your Business

A different kind of poison Every time I see the lights on a Christmas tree blinking on and off, I am reminded of the old adage, “One person’s medicine is another person’s poison.” Flickering lights in an office, factory or residential home can be more than an annoyance.

Frank Kinder

The Power Quality of Life

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Your Business

What do these statements have in common? • Lightning doesn’t strike the same place twice. • Electrical utilities correct a fault by sending a power surge to clear a short in a service line, transformer or other load grid short circuit.

Article 220-Branch Circuit, Feeder and Service Calculations

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Your Business

Hospitals have a priceless ‘product’—human life When people think of high-reliability facilities, most often it is the financial data centers and the semiconductor plants that come to mind.

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Systems

Cooking Equipment Calculations, Part IV 220.19 Electric Ranges and Other Cooking Appliances

A Hidden Shock

W. Creighton Schwan

Length of Secondary Conductors Without Overcurrent Protection and More

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Safety

The problems with multiwire circuits On March 20, 1883, a U.S. Patent was issued to Thomas A.

PQ’s (Second) Most Wanted

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Systems

CODE CITATIONS Article 200 Use and Identification of Grounded Conductors Article 210 Branch Circuits Article 240 Overcurrent Protection Article 300 Wiring Methods Article 334 Nonmetallic-Sheathed Cable: Types NM, NMC and NMS Article 362 Electrical Nonmetallic Tubing: Type ENT Article 450 Transformer

Abandoned Fire Alarm Cables, Conductor Derating and More

| March 2004

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Your Business

Continuing to look at power quality’s biggest enemies As a continuation of last month’s article, here are a couple of additional “pictures” of the most popular PQ criminals for the office wall to help quickly identify what the squiggly lines mean and to find the source of problems.

Article 220-Branch Circuit, Feeder and Service Calculations

| March 2004

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Systems

CODE CITATIONS Article 90 Introduction; Article 110 Requirements for Electrical Installations; Article 210 Branch Circuits; Article 220 Branch-Circuit, Feeder and Service Calculations; Article 250 Grounding; Article 300 Wiring Methods; Article 310 Conductors for General Wiring; Article 400 Flexible

Wiring Air Conditioning and More

| March 2004

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Your Business

Cooking Equipment Calculations, Part III 220.19 Electric Ranges and Other Cooking Appliances Article 220 of the National Electrical Code contains specifications for calculating branch-circuit, feeder and service loads.

Installing a Service Disconnect

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Systems

CODE CITATIONS Article 210 Branch Circuits Article 250 Grounding Article 300 Wiring Methods Article 310 Conductors for General Wiring Article 334 Nonmetallic Sheathed Cable: Types NM, NMC and NMS Article 422 Appliances Article 518 Places of Assembly Article 700 Emergency Systems Wiring air condition

Mark C. Ode

Power Quality’s Most Wanted

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Systems

Many changes have occurred to the National Electrical Code (NEC) since the first NEC was published on Aug. 31, 1897. Even though the electrical industry was in its infancy, this “first” NEC was remarkably insightful and has withstood the test of time.

Back to Basics Makes Sense

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Your Business

Even without the pictures on the post office wall or the television show of almost the same name, being able to recognize the most popular power quality “criminals” can help quickly find the source of problems.

Cooking Equipment Calculations, Part II

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Your Business

At a recent Technology Committee meeting for a local school district, there was considerable discussion about the lack of responsiveness in getting electrical infrastructure issues fixed.

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Your Business

Specifications for calculating branch-circuit, feeder and service loads are in Article 220 of the National Electrical Code. This article is divided into four parts: I. General, II. Feeders and Services, III. Optional Calculations for Computing Feeder and Service Loads and IV.

Speaking to Strengths

Branch Circuit Feeder and Service Calculations

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Your Business

At the recent Power Quality World Conference, I chaired a session on “Specifying and Purchasing PQ Equipment.” Afterward, I met one of the presenters from an electric utility who said he planned to bring his lawyer with him to the session the next day.

Wall Space in Dwelling Units, Bonding Metal Water and More

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Your Business

Article 220 contains provisions for calculating branch-circuit, feeder and service loads. Following the requirements set forth in this article will provide the minimum size branch circuit, feeder or service.

Resizing Service or Feeder Loads

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Codes & Standards

CODE CITATIONS Article 110 Requirements for Electrical Installations Article 210 Branch Circuits Article 250 Grounding Article 310 Conductors for General Wiring Article 314 Outlet, Device, Pull and Junction Boxes; Conduit Bodies; Fittings; and Manholes Article 410 Luminaires (Lighting Fixtures), Lam

Mark C. Ode