Arc Flash & Electrical Safety: December 2006

Wednesday, December 27, 2006

Electrical Inspection Risks

While I was looking through back issues of IAEI Magazine I found an interesting article that discusses the risks that electrical inspectors face, and how those risks can be reduced. It talks about the following topics:

Risk From Job Site Hazards

Risk of Not Being a Qualified Person

Risk of Improper Personal Protective Equipment

Risk From Explosions, Arc Flash and Arc Blast

Risk of Bodily Harm From Property Owners

The article concludes by discussing "Winning Through Planning".

For example, since my experience primarily involved providing services to utilities and major manufacturing facilities, I had not considered the risk inspectors face from property owners who do not want their property inspected. The article makes this recommendation:

"Most of the problems dealing with the public can be mitigated with some planning prior to the inspection. If the inspection deals with a low income area, it’s helpful for the inspector to know the financial resources that may be available to the property owner for repairs or corrections."

Labels: Electrical Hazards

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Friday, December 22, 2006

Changes to the NEC Require More Arc Flash Labeling

The following is from IAEI Magazine (International Association of Electrical Inspectors). It provides an overall analysis of changes to Part 1 of NEC-2008. Included in those changes is a change to the labeling requirements for arc flash hazards.

The specific revision is to Article 110 Requirements for Electrical Installations. It is identified as Revision: 110.16 Flash Protection. The modified language states: "Electrical equipment such as… shall be field marked to warn qualified persons of potential electric arc flash hazards."

This revision broadens the requirement for labeling. The IAEI article states: "Previous requirements of this section were limited only to the types of equipment actually identified in the rule. By including the words, 'equipment such as' the concept of applicability is expanded to all equipment types that are likely to require examination, adjustment, servicing, or maintenance while energized. This requirement applies to items such as enclosed circuit breakers, some transformers, and other equipment not specifically included in the previous text."

A second revision related to arc flash labeling puts a specific limitation on the types of dwellings covered by arc flash labeling requirements. It differentiates between apartment complexes, which are required to label arc flash hazards, and one and two family homes, which are not required to have arc flash labeling--although the hazard may still exist. Please read the IAEI article for the details of all the modifications to the NEC.

Labels: NEC - Arc Flash Hazards

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Tuesday, December 19, 2006

Field Marking of Arc Flash Hazards

The following is from a technical paper titled "Field Marking of Arc Flash Hazards - Avoid Workers' Injuries & Equipment Damage."

Published by the Resource Center, National Electrical Code, this paper was written by Mark Ode, a staff engineering associate at Underwriters Laboratories, Inc. It provides a lot of information about arc flash safety, and in particular points out that arc flash labeling is important.

As it is coming to a conclusion, the paper states the following concerning arc flash labeling:

"Section 110.16, covering flash protection marking, has been added to the 2002 NEC. It provides a link to NFPA 70E and OSHA for requirements dealing with arc flash hazards. It requires field marking for switchboards, panel boards, industrial control panels and motor control centers. The marking is intended to warn qualified persons of flash hazards where the equipment is likely to be examined, adjusted, serviced or maintained while energized. The marking must be located on the equipment in such a manner as to be clearly visible to qualified personnel before they commence work on the equipment."

"Make sure this field marking is applied in a very visible location so when you work on electrical equipment while energized, you are very aware of the hazards involved. Take the necessary safety steps to ensure that no one suffers serious burns or injuries."

Labels: Arc Flash Labeling

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Monday, December 18, 2006

Loose Tool Falls, Causes Arc Flash Injury

A report put out by SHARP* describes an arc flash injury that was caused by a falling tool. A small tool fell into an energized breaker panel coming into contact with energized wires.

The report also includes six recommendations for preventing accidents such as this.

Another report put out by SHARP describes how two electricians were injured by an arc flash when a ground wire touched an energized circuit. One electrician sustained second and third degree burns covering nearly 50% of his body. He required surgery for removal of destroyed skin and restorative skin grafts. He needed physical therapy for nearly a year.

*SHARP is the Safety and Health Assessment ans Research for Prevention (SHARP) program at the Washington State Department of Labor and Industries.

Labels: Arc Flash Accidents

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Friday, December 15, 2006

Easy To Understand Explanation of Arc Flash

Normally I'm looking for detailed information related to arc flash. But at times it may be useful to have a simplified explanation that anyone can understand. When I saw the explanation of arc flash on the Alliant Energy web site, I was impressed. It gives an easy to understand explanation of arc flash and the steps that should be taken to prevent arc flash injury. Clear, easy-to-understand graphics provide visual descriptions of what happens during an arc flash incident.

You'll find the Alliant Energy arc flash web page at: http://www.alliantenergy.com/docs/groups/public/documents/pub/p015092.hcsp

Labels: Understanding Arc Flash

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Thursday, December 14, 2006

Preventing Arc Flash Injuries

I just found an excellent article about "Preventing Arc Flash Injuries" in Occupational Hazards Magazine. This article provides more detail than most in describing what needs to be done to establish a safety practices that prevent arc flash injuries.

The article points out that "Many managers and supervisors are asking 'why the interest' and more to the point, many are saying, 'I don't see how this affects me or my people. We have never had an arc flash incident.'"

Statistics from from a National Institute for Occupational Safety and Health study show why taking measures to prevent arc flash injuries is important. In the ten year period of1992 through 2001 there were 17,101 injuries caused by electric arc flash burns.

This article lists six steps for preventing arc flash injuries:

Step 1. The Arc Flash Hazard Analysis
Step 2. Gather the Information
Step 3. Perform an Arc Flash Study
Step 4. Choose the Proper PPE
Step 5. Label Your Equipment
Step 6. Train Your Workers

Labels: Preventing Arc Flash Accidents

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Wednesday, December 13, 2006

Three Injured By Arc Flash - Video

Magna Electric has a video on their web site that shows an arc flash incident that injured three workers. The video was taken by a security camera.

What I hope you notice in these videos is that arc flash is a hazard that needs to be taken very seriously. There are five to ten arc flash incidents daily. It can happen in your facility. Please read this blog and our web site for more information about arc flash and NFPA 70E.

Labels: Arc Flash Accidents, Work Place Safety

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Tuesday, December 12, 2006

Video of World's Largest Jacob's Ladder

Today and tomorrow we'll be taking a look at some videos. Today's arc flash video is in the post below.

This first one is a huge arc, the world's largest Jacob's ladder.

The above incident is described on the http://www.arcfault.org web site as:

"This is a 3 phase 500KV motor operated disconnect that is NOT intended to be opened under load. There is a switcher that is designed to open under load in the circuit and then this disconnect opens. In this case, one phase of the switcher failed to open, resulting in one phase of the disconnect opening under load. "

The result was a huge arc that was eventually stopped when an operator manually opened a shutoff switch.

The utility knew there was a problem and were video taping the operation of the disconnect to help locate and identify the problem.

Although this is not an arc flash (see today's other post), it is spectacular and interesting to see.

Labels: Arc Flash

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Video of Arc Flash Demonstration

What does an arc flash explosion look like? A 480v 3-phrase demonstration of an arc flash was set up in a laboratory and video taped. An arc flash is usually caused by something, most commonly dirt or debris, causing a short circuit. For example, here is a report of an arc flash incident caused by a tool that fell into a breaker panel.

In this demonstration the arc flash was intentionally started by placing wires across the three copper bus bars. This created the short circuit normally caused by dirt or debris. Power (480v) was then applied to the bus bars for about 1 second.