What’s going on? – IEC 60479-1 and IEC 60479-2 DC body resistance

 

This document reviews the DC body resistance and pulsed DC content of the following two standards:

·      IEC 60479-1:2018, Effects of current on human beings and livestock – Part 1: General aspects
·      IEC 60479-2:2019, Effects of current on human beings and livestock – Part 2: Special aspects

Cross references are made to other documents:

·      Panescu, D., et al: Transthoracic Ventricular Fibrillation Charge Thresholds
·      Nute, R: Body resistance — a review
·      Kroll, Perkins, Pratt, Stuart, Bury and Panescu, Safety of a High-Efficiency Electrical Fence Energizer
·      IEC 60990:2016: Methods of measurement of touch current and protective conductor current
·      Perkins, P: TOUCH CURRENT measurement; Showing how it works, Parts 1 to 3
·      IEC 61201:2007, Use of conventional touch voltage limits – Application guide
·      IEC TR 60479-5:2007, Effects of current on human beings and livestock – Part 5: Touch voltage threshold values for physiological effects

Readers must be aware of the document disclaimer and convince themselves, through reading the referenced standards and papers, that the interpretations herein are correct before acting on them.

Assembly or integrated circuit or hybrid protector?

In the SPD testing world there has always been a conflict between those who want to test the SPD “as is” and those who want to take the SPD apart to put copper shorts and the like inside – “open the box”.

Recently one manufacturer, who produced a component that combined an MOV and GDT, was frustrated by a test laboratory that wanted to separate the component into its MOV and GDT parts and test each independently - “open the box”. It mattered little to the test laboratory that the performance of the separate parts would not be the same as when in combination.

This led to the thought “What is the difference between an assembly, integrated circuit and hybrid protector”. It may come as a shock to some that an integrated circuit doesn't need to be something like you get from companies like Intel or Texas Instruments. How the IEC defines in this area is reviewed here, concluding with some recommendations.

What’s going on? – IEC 62368-1 Edition 3, AC mains port protection component requirements

This is an advanced level tutorial on the IEC 62368-1 Edition 3 AC mains port protection component requirements for metal-oxide varistor, MOV, gas discharge tube, GDT, series connected MOVs and series connected MOV and GDT combinations. This document reviews the document entries under these topics, provides commentary and worked examples. Key outcomes are that generally Live to Protective Earth and Neutral to Protective Earth protection for pluggable Type A equipment requires a series connected MOV GDT circuit and that the GDT sparkover required is 2 kV or more. Standards are often difficult to read and interpret. Readers must be aware of the document disclaimer and convince themselves, through reading the referenced standards, that the interpretations herein are correct before acting on them.