Two Measures, Two Levels
What is a “level of protection”? What are “measures of safety”? Why do they apply only to electric shock and not to other injuries?
Markings and Other Aggravations
Why? Why is it that one of the biggest aggravations in product safety is that of markings? For some reason, it seems that we can never get the markings right the first time. Furthermore, it seems that markings that have been acceptable for years will suddenly go bad.
Fire Prevention
The best solution to fire - any fire - is to prevent fire in the first place.
Fire Enclosures
In our last issue, I discussed heating, pyrolysis, and combustion processes necessary for a fire to occur. I discussed that flame-retardant materials continue to burn in the presence of a heat source. I want to... Read More...
Electrically-Caused Fire
Probably the single most frequently occurring and most misunderstood issue in electronic product safety is electrically-caused fire. I thought I would review fire processes in plastics materials (the most common flammable construction material in electronic products).
Transients in Secondary Circuits
Richard Nute examines how transformers behave when subjected to transient overvoltage, both magnetically and capacitively.
Leakage Current Measuring Circuits
The leakage current measuring circuits in IEC 950 and those in North America are exactly the same.
The Myth of Accessibility
Almost every safety standard has requirements addressing the accessibility of certain parts.
Working Voltage, Electric Strength, and Spacings
For the purposes of safety, what is “working voltage,” and what is its relevance to the safety of the equipment?
Testing Safety Into Products
In a recent discussion with a third-party certifier, there was an implication that a product cannot be deemed safe until it has been tested. It was further implied that the outcome of the testing could not be p... Read More...