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 […]
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 […]
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 […]
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 […]
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 […]
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. […]
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 […]
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 […]
2017 NEC 240.87 Instantaneous Trip
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 […]
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 […]
Lock Out / Tag Out Simple vs. Complex
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 […]
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 […]
Have you ever read IEEE 1584?
Just Curious – Have you ever read IEEE 1584 – IEEE Guide for Performing Arc Flash Hazard Calculations? -All of it -Some of it -No Click to ANSWER.
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). […]
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 […]
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 […]
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 […]
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 […]
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 […]