arc flash protection boundary definition

Nominal System Voltage Range, Phase to Phase The table below has been adapted from NFPA 70E, Table 130.4(E)(a) Shock Protection Approach Boundaries to Exposed Energised Electrical Conductors or Circuit Parts for Alternating Current Systems. In Europe we would know this person as an electrically skilled or instructed person, in other words a competent person, again stating the minimum distance that should be maintained from exposed live parts in order to prevent electric shock. Restricted Approach Boundary- approach by a Qualified Person. Typically, in the UK, switchpanels contain live parts within enclosure and it is only when such enclosures are open and live parts are accessible does an issue exist.

In Europe we would know this as an ordinary person, that being a person who is neither electrically skilled nor instructed and is the minimum distance that a non-competent person can approach parts that are energized and dangerous. Limited Approach Boundary- approach by Unqualified Persons. This article looks at the arc flash boundary, however, before moving on it is work discussing the limited and restricted approach boundaries that in fact relate to electric shock protection, rather than arc flash control. Dependant on the remit of any arc flash study carried out, labels fitted to switchgear may make reference to one, or all of the above boundaries. Arc Flash Boundary DistancesĪccording to NFPA 70E, three boundaries exist, these are Limited Approach Boundary, Restricted Approach Boundary and Arc Flash Boundary. Compliance Director, Andy Linley, discusses Arc Flash Boundary distances, what they are and factors affecting them.

Arc flash protection boundary definition