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Technical Articles

NFPA 70E

Include Date on Arc Flash Label?

December 20, 2016

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

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2015 NFPA 70E Changes

December 9, 2016

The following is an article that I wrote a few years ago listing the major changes for the 2015 edition. It was originally published in the May 2014 issue of Electrical Contractor Magazine and is provided here as a resource for your use. Change Is On The Way! 2015 NFPA 70E Published: May 2014 – Electrical Contractor Magazine By Jim Phillips Deja vu? Déjà vu is that feeling you get when you think you have seen or done something before. NFPA

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ATS Protection and UL

November 29, 2016

In looking at the latest edition [7th] of UL 1008 for transfer switches I came across the following: “The circuit breaker must include an instantaneous trip response and shall not include a sort time trip response” as it relates to switches tested per 9.13.3.10 & 9.1.2.3. It seems different manufactures have different interpretations. So does this disqualify any breaker with an adjustable STPU / STD setting from protecting a 3-cycle [0.05sec] any breaker rated switch, even if the breaker has

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Hot Stick Testing

November 28, 2016

Question: Everyone, I got this question from a client. He asked if it’s necessary to have their hot sticks tested? Understand this company has nothing higher than 480 volts on site and only uses these hot sticks to switch on and off 480 volt 30- to 200 amp bus duct fused disconnect switches. The bus in this factory is hanging well above the floor. If an employee needs to reach a bus plug, he uses a hot stick to access

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Regenerative Drive Contributions to Upstream Fault

November 25, 2016

Is there any information on what a regenerative drive will allow a motor to contribute to an upstream fault? I know ANSI has some standards for motor contributions based on <50HP or >50HP for across the line starters. We have some DC motors with regen drives connected to a 480VAC system and I want to model the contributions of the motors on the upstream switchgear. A few of these motors are 500HP or bigger. We used to use Easypower and

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Arc Flash Labels-PPE Category

November 22, 2016

In the NFPA 70E-2015 Handbook, page 122, 130.5(D) states incident energy or PPE category shall be on the equipment arc flash label, but not both. Yet when reviewing Annex H in the NFPA 70E-2015 handbook, on page 279 it states “Arcflash PPE categories may be applicable when using incident energy method to perform an arc flash risk assessment. When performing an incident energy analysis, the arc flash labels created may include an arc flash category”. Am I missing something or

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Reducing Arc Flash I/E At Fire Pump Controllers

November 21, 2016

Question: What are you guys recommending to reduce incident energy levels on fire pump controllers fed directly from the secondary side of utility transformers? Answer: Can’t be done. This is a common practice but is very illegal in most cases. NEC is very specific in that overload protection (ie, overload relay) is eliminated and short circuit protection only remains. I have no idea why and I’ve had multiple fire marshals actually try to tell me that fire pumps get ZERO protection

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Work on an energized disconnect

November 18, 2016

Recently, a client asked if there was something I could point to in the NFPA 70E Standard that specifically prevented a qualified electrician from working on a disconnect after it was shut off, but with the line side left energized? I asked exactly what he meant? He said our electricians sometimes need to disconnect one of our 480 volt welders for repair or to be serviced. We sometimes have more than one welder on a circuit, so shutting off the

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120 Volt Arc Flash

November 16, 2016

I believe it to physically impossible to sustain an arc flash at 120 V but can someone point me to the proof? Can someone indicate where a code specifically states no arc flash PPE is required at 120 VAC? READ MORE.           About 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,

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Arc Flash Label Updating – How Many Times?

November 14, 2016

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

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