17.3.4.5 Location of SPD
IEEE Std 1100 [27] addresses the filtering and grounding of service lines and other
conductors that ingress/egress the LPS boundary zones, and IEC 62305-4 [18]
specifies the appropriate arrangement of SPDs within lightning protection zones,
particularly at transition points and with a special emphasis on the coordination of
an SPD with the equipment to be protected. IEEE C62.41 [28] offers guidelines for
the application of SPDs.
The following are some important factors to be considered when evaluating the
need for and installing SPDs.
† SPDs appropriate for lightning protection of low-voltage installations are
designed to handle only a portion of the total lightning current.
† The protection levels of the selected SPDs must meet the requirements for the
insulation coordination and the immunity levels of the equiment to be protected
(IEC 61000-4-5 [29]).
† SPDs should be located at well identified critical zone interfaces of the LPS, and in
particular, at interfaces of voltage levels.
† SPDs should be located as close as possible to the equipment to be protected, with
the ground conductor being as short and straight as possible.