Liability and Legal Action

It’s no secret that the United States is a very litigious country.

Sometimes the more “interesting” interpretations that people use regarding codes, standards, design etc. tend to be more influenced by fear of lawsuits. I have had this conversation with many people over the years.

There are many reasons that legal action may be taken but this week’s question is very specific. It refers to: Liability from accident, injury, death, equipment failure. It applies to both the Plaintiff and Defendant.

Since this can be a sensitive topic, one of the answers is “can not answer”
Here it is:

Have you or your company/client ever been involved in legal action involving liability?
Yes
No
Can not answer

Stories are welcome if you are able to comment. ANSWER

Include Date on Arc Flash Label?

According to the 2015 Edition of NFPA 70E 130.5(2), The arc flash risk assessment “…shall be reviewed periodically, at intervals not to exceed 5 years, to account for changes in the electrical distribution system that could affect the results of the arc flash risk assessment.”

According to 130.5(D) Equipment Labeling, the date is not listed as a requirement for including on the label. However, many believe the date is an important aspect of the label in order to keep track of the “5 years” time limit.

Here is this week’s question:

Do you feel the date should be included on the arc flash label?
Yes
No

ANSWER

How Many Arc Flash Labels on Equipment?

Question of the Week

Some equipment may have multiple arc flash labels for a variety of reasons.

  • Different operating configurations
  • Equipment is long/large – including busway
  • Equipment has different incident energy for main/feeders such as some switchgear.

There may be other reasons as well.

This week’s question:

What is the greatest number of arc flash labels you have seen/used on electrical equipment?
1
2
3
More than 3 (how many?) ANSWER

Face equipment or face away during switching?

Weekly Question:

This week’s question was submitted from one of our forum members. I will post it here

When locking out or resetting a tripped breaker on a CAT 4 system (actually extreme danger), I have one electrician that says he feels more comfortable facing the distribution than facing away. He argues that the shield will protect him better than the Balaclava. He also says that the force needed to reset a tripped (1200 Amp) breaker is easier when facing the breaker. Our lockout rules say to face away, close your eyes and hold your breath (and pray), using your left hand. Which is safer?

To summarize, here is this week’s question:

When switching equipment, do you believe it better to face the equipment or face away.
Face equipment
Face away
Doesn’t matter
Something else

READ MORE

If you have a question you would like to see submitted as a “Question of the Week” pass it along to me and I’ll get it posted! – Jim

Arc Flash Label Updating – How Many Times?

NFPA 70E requires that an Arc Flash Risk Assessment be updated when a major modification or renovation takes place. It shall be reviewed periodically, at intervals not to exceed 5 years, to account for changes in the electrical distribution system that could affect the results of the arc flash risk assessment. Countries outside of the US that do not use NFPA 70E may have a similar label review/updating requirement.

NFPA 70E further states that where the review of the arc flash hazard risk assessment identifies a change that renders the label inaccurate, the label shall be updated.

What is the maximum number of times you have updated any arc flash label since first applied?
-Still have original labels
-Updated once
-Updated twice
-Updated more than twice
-No labels yet
-I don’t do labeling

ANSWER QUESTION

Maximum Short Circuit Current

The intensity of an arc flash is dependent on the magnitude of short circuit current. Lower voltage systems (less than 600 volts) tend to have the highest short circuit currents. Here is this weeks question:

What is the maximum short circuit current that you have seen?

less than 50 kA
greater than 50 kA
greater than 100 kA
greater than 150 kA

ANSWER

ANSI Z535 – Series of Standards for Safety Signs and Tags

Many safety labels use either Caution, Warning or Danger with a specific color associated with it.

The U.S. National Electrical Code and NFPA 70E both reference ANSI Z535 to provide guidance regarding effective words, colors and symbols for signs and labels that provide warning about electrical hazards.

Other countries may have a different standard for guidance.

Here is this week’s question:

How familiar are you with the ANSI Z535 Series of Standards for Safety Signs and Tags

Not in the U.S. / Doesn’t apply
Not Familiar
Know about it
I’ve read it

ANSWER QUESTION

Maximum distance where arc flash label is still readable

This week’s question is very subjective and is based on all kinds of variables such as lighting, eye sight etc. For an average person under normal conditions:

What is the MAXIMUM distance where the typical arc flash label details are still readable?

Less than 4 ft. (1.2 M)
Between 4 and 8 ft. (1.2 to 2.4 M)
Between 8 and 12 ft. (2.4 to 3.7 M)
Something greater than 12 ft. (3.7 M)
It depends

ANSWER QUESTION

2017 NEC 240.87 Instantaneous Trip

Download FREE Arc Flash Calculations

The NEC requires that where a circuit breaker’s highest continuous current trip setting is rated or can be adjusted to 1200 Amps or higher, a method for reducing the arc energy must be provided.

The 2014 Edition of the NEC provided a list of methods which included: zone-selective interlocking, differential relaying, energy-reducing maintenance switching and energy-reducing active mitigation systems or an approved equivalent means. The device’s instantaneous trip function was excluded from the list.

The 2017 Edition of the NEC now permits the use of the device’s instantaneous trip unit or instantaneous override as long as there is sufficient arcing short circuit current for it to trip. IEEE 1584 – IEEE Guide for Performing Arc-Flash Hazard Calculations is referenced in this section as a method for calculating the arcing short circuit current.

Since the National Electrical Code (NEC) is a U.S. based standard, this requirement may not be applicable to those in other countries. It would be interesting to hear the different views.

With that long introduction, here is this week’s question:

Will you/your clients begin using the instantaneous to reduce arc flash energy for breakers 1200A and greater?

Yes
No
Doesn’t apply
We were using it anyway/already
ANSWER QUESTION

 

About Jim Phillips: Electrical Power and Arc Flash Training Programs – For over 30 years, Jim Phillips has been helping tens of thousands of people around the world, understand electrical power system design, analysis, arc flash and electrical safety.

NFPA70E 2018 Update video by Jim PhillipsJim is Vice Chair of IEEE 1584, International Chairman of IEC TC78 Live Working and Steering Committee Member – IEEE/NFPA Arc Flash Collaborative Research Project. He has developed a reputation for being one of the best trainers in the electric power industry.  Learn More


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 by Jim Phillips Click Here

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Do you use equipment/methods based on IEC Standards?

This week’s “Question of the week” is coming from Frankfurt, Germany. This week I have the privilege of attending the International Electrotechincal Commission’s 80th General Meeting as the International Chairman of IEC TC78 Live-Working which has 35 standards/publications including Arc Flash Protection.

The IEC prepares and publishes International Standards for all electrical, electronic and related technologies. Since the Arc Flash Forum is an international community, here is this week’s question:

Do you (your company) use any electrical equipment/methods based on IEC standards?
Yes
No
Not sure

ANSWER QUESTION

Lock Out / Tag Out Simple vs. Complex

BUY NOW: 2018 NFPA 70E Changes Part 1

OSHA and NFPA 70E refer to a Simple LOTO as involving only one person/conductors/circuit part(s). A Complex LOTO is when there are conditions such as more than one person/circuit/shift/source involved – A complex LOTO has significantly more requirements.

Here is this week’s question:

Have you ever performed a complex LOTO?
Yes
No

ANSWER

 

About Jim Phillips: Electrical Power and Arc Flash Training Programs – For over 30 years, Jim Phillips has been helping tens of thousands of people around the world, understand electrical power system design, analysis, arc flash and electrical safety.

NFPA70E 2018 Update video by Jim PhillipsJim is Vice Chair of IEEE 1584, International Chairman of IEC TC78 Live Working and Steering Committee Member – IEEE/NFPA Arc Flash Collaborative Research Project. He has developed a reputation for being one of the best trainers in the electric power industry.  Learn More


Arc Flash & Electrical Power Training Classes
 by Jim Phillips Click Here

Arc Flash & Electrical Power Training Products by Jim Phillips Click Here

Sign-up for my monthly publication “Grey Matter” which contains news about new standards, conferences, technical articles, Electrical Engineering news and more! Click Here

IEEE 1814 – Have you heard of it?

IEEE 1814 Recommended Practice for Electrical System Design Techniques to Improve Electrical Safety

The overview of this standard is that the Recommended Practice will communicate “electrical safety by design” concepts and their benefits. Current standards and codes place minimum requirements on electrical system designers and manufacturers that yield functional, reasonably safe electrical installations. The final product of this working group will capture, in one location, a wealth of “electrical safety by design” concepts that have been published in recent IEEE papers and in other industry sources. Visit IEEE 1814.

Here is this week’s question:

Until reading it here, have you heard of IEEE 1814?
Yes
No

ANSWER HERE.

Using Grounding Resistors

One of the forum member’s posts prompted this weeks question of the week. It is about grounding, more specifically – high and low resistance grounding. (some may use reactance grounding). Rather than having a solidly grounded system or a delta connected system, some will use a grounding resistor to limit the line-to-ground short circuit current that flows during a fault.

This week’s question:
Does your company (or clients) use grounding resistors anywhere in the power distribution system?

No
Hi Resistance Grounding
Low Resistance Grounding
Both Hi and Low
It depends – Many locations/clients
Doesn’t apply to me

ANSWER QUESTION

NFPA 70E and Improved Electrical Maintenance

The duration of an arc flash can be greatly affected by the condition of electrical protective devices – i.e. circuit breakers, relays etc. NFPA 70E has been placing an increased emphasis on equipment being properly maintained.

Has your company/client increased the emphasis on electrical maintenance as a result of 70E?

Yes
No
Many clients – it depends

CLICK to answer.

Tested vs. Engineered Series Ratings

One more question about series ratings. NEC 240.86 addresses series ratings “Selected Under Engineering Supervision in Existing Systems” and “Tested Combinations” Please refer to last week’s post and NEC 240.86 for specific application details.

Do you use “Engineered/Selected under engineering supervision” or “Tested Combinations” series ratings

– Engineered/Selected under engineering supervision
– Tested combinations
– Both
– None

READ MORE

Series Ratings NEC 240.86

The National Electrical Code article 240.86 addresses series ratings with the following:

Where a circuit breaker is used on a circuit having an available fault current higher than the marked interrupting rating by being connected on the load side of an acceptable overcurrent protective device having a higher rating, the circuit breaker shall meet the requirements specified in (A) or (B), and (C).

(A) Selected Under Engineering Supervision in Existing Installations. The series rated combination devices shall be selected by a licensed professional engineer engaged primarily in the design or maintenance of electrical installations. The selection shall be documented and stamped by the professional engineer. This documentation shall be available to those authorized to design, install, inspect, maintain, and operate the system. This series combination rating, including identification of the upstream device, shall be field marked on the end use equipment. For calculated applications, the engineer shall ensure that the downstream circuit breaker(s) that are part of the series combination remain passive during the interruption period of the line side fully rated, current-limiting device.

During the early 1980’s there were some problems with series ratings and tested combinations were introduced. Series rated test standards in accordance with U.L were developed and circuit breaker manufacturers begin to provide tables with their listed series ratings like we see today. 240.87(B) states

(B) Tested Combinations. The combination of line-side overcurrent device and load-side circuit breaker(s) is tested and marked on the end use equipment, such as switchboards and panelboards.
Informational Note to (A) and (B): See 110.22 for marking of series combination systems.

240.87 (C) addresses the situation where short circuit contribution from motor’s a.k.a. “motor contribution” may occur between the line side and load side devices that make up a series rating. The consideration is as follows:

(C) Motor Contribution. Series ratings shall not be used where (1) Motors are connected on the load side of the higher rated overcurrent device and on the line side of the lower-rated overcurrent device, and
(2) The sum of the motor full-load currents exceeds 1 percent of the interrupting rating of the lower-rated circuit breaker.

An example of a series rating may be a breaker that normally has an interrupting rating of 22,000 Amps but when protected with upstream fuses of a specific size and class, may have a series rating of 100,000 Amps. This must be either a listed combination or determined under engineering supervision as stated above in 240.86 (A)

Those that consider using series ratings should thoroughly review the requirements of 240.87.

With all of that information, here is this week’s question.

Does your facility/client’s facility use series ratings?
– Yes
– No
– Multiple sites – some do
– Don’t know
– Doesn’t apply to me

CLICK to answer and review discussion.


NFPA70E 2018 Update video by Jim PhillipsAbout Jim Phillips, P.E.: Electrical Power and Arc Flash Training Programs – For over 30 years, Jim Phillips has been helping tens of thousands of people around the world, understand electrical power system design, analysis, arc flash and electrical safety. Jim is Vice Chair of IEEE 1584 and International Chairman of IEC TC78 Live Working. He has developed a reputation for being one of the best trainers in the electric power industry, Learn More.

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Arc Flash Boundary – Calculated, Larger, Something Else?

It has been a while since a question of the week was asked about the Arc Flash Boundary. This is the distance from a prospective arc flash where the incident energy is 1.2 cal/cm^2 which is the generally accepted value for the onset of a second degree burn. IEEE 1584 has a method for calculating this distance.

Since electrical safety practices continue to evolve, this week’s question is about the Arc Flash Boundary. Although the AFB is required to be on the warning label and is a calculated value, many are opting to keep unprotected/unqualified workers further away from a possible arc flash during live work (which should be kept to a minimum). This week’s question:

For your (client’s) electrical safety practices, do you use:
Select up to 2 answers

Calculated AFB
Something larger (please explain)
Keep unprotected people out of the electrical room
It depends

Please feel free to elaborate READ MORE

Overdutied Protective Devices and Catastrophic Failures

People seem to love to watch videos of electrical explosions. One type of failure is when a protective device is applied beyond its interrupting rating and catastrophically fails (explodes) when it has to interrupt a short circuit. Although this does not happen for every overdutied device, it could happen. That is the main reason for performing a short circuit study – to identify these types of deficiencies so they can be corrected.

So with that intro, here is this week’s question.

Have you/clients ever had an overcurrent device catastrophically fail when it interrupted a fault?
Yes
No

READ MORE