8.3.3 Equipment Data Electrode Configuration

If using the IEEE 1584 Guide for Performing Arc Flash Hazard Calculation 2018, it will be necessary to determine the electrode configuration at the equipment that is being modelled. Electrode configuration is the term used for the orientation and arrangement of the electrodes used in the testing performed for the IEEE 1584 model development. These are detailed in the IEEE 1584 guide and there is some further guidance to be had within annexe C and annexe G2 of said guide. The following information is presented to further assist the engineer to determine which configuration is necessary when applying the IEEE 1584 model in a European context.

There are five different electrode configurations used in the laboratory conditions to create the formulae and these are as follows.

  • VCB: Vertical conductors/electrodes inside a metal box/enclosure.
  • VCBB: Vertical conductors/electrodes terminated in an insulating barrier inside a metal box/enclosure.
  • HCB: Horizontal conductors/electrodes inside a metal box/enclosure.
  • VOA: Vertical conductors/electrodes in open air.
  • HOA: Horizontal conductors/electrodes in open air.

The task is to establish which electrode configuration to use as the choice will determine not only the arcing current but also the incident energy & arc flash boundaries. If there are some doubts about which configuration is the best fit for the actual configurations on site, then the quick calculators provided with this guide will allow some “what if” type considerations to work out which is the best fit in terms of worst-case scenarios. This may be necessary because there may be multiple configurations in one piece of equipment. Examples of Electrode Configurations

Configuration Description Enclosure Examples
VCB Vertical conductors Metal Metal Cut Outs, Industrial Service Units, factory-built switchboard assemblies, LV isolators and switch fuse units.
VCBB Vertical conductors into insulating barrier Metal Busbar trunking systems, tap off units, factory-built switchboard assemblies
HCB Horizontal conductors Metal Transformer LV cable boxes, Pavement mounted link boxes, Busbar trunking systems, tap off units.
VOA Vertical conductors Open Air Terminations onto overhead lines, Live LV Jointing, Pole mounted transformer terminations.
HOA Horizontal conductors Open Air Open transformer pad terminations, overhead line spans, Live LV Jointing, Open LV feeder pillars.