YSI DIQ/S 182 XT-4 System 182 XT-4 - Manual (Page 21)

System 182 XT-4 Installation
3 - 7 ba76026e01 01/2012
3.5 Installation guidelines for lightning protection
When using the IQ S ENSOR N ET instrumentation, particularly in outdoor
areas, adequate protection against (electrical) surges must be
provided. A surge is a summation phenomenon of surge voltage and
surge current. It is generated through the indirect effect of a lightning
event or switching operation in the mains, in the grounding system and
in information technology lines.
To be adequately protected against the damaging effects of surges, an
integrated concept of the following protective measures is required:
 internal device-related protective measures and
 external protective measures of the installation environment.
The internal device-related protective measures are already integrated
in the YSI online measuring technology as so-called 'lightning
protection' (see chapter 9 T
ECHNICAL DATA ).
The external protective measures of the installation environment can
be carried out with respect to the following guidelines:
1 All lines of IQ S ENSOR N ET systems must be
a) installed inside (or else close to) the grounded metallic mounting
constructions, e.g. handrails, pipes and posts if possible
b) or, particularly in the case of longer lines, laid in the ground.
Background: The formation of highly lightning hazardous inductive
loops between the cables and ground is avoided through the low
clearance of the grounded metal construction or by installation in the
ground.
2 Only the SNCIQ or SNCIQ-UG cable material must be used. This
cable material, particularly the high line cross section of the cable
shielding (1.5 mm²), is an important prerequisite for the hazard-free
discharging of the surge without inadmissibly high overvoltages
developing along the line at the same time that could have a
damaging effect on the individual IQ S
ENSOR N ET components. It is
not recommended to use cables from other manufacturers with
usually appreciably lower shielding conductor cross sections.
3 All metallic mounting constructions, handrails, pipes, posts etc. on
which MIQ modules are installed must be connected to the local
potential equalization system and the grounding system or must be
individually sufficiently grounded locally according to the codes of
practice.
For the individual grounding of the measuring point the mounting
construction must be solidly connected by means of a large-area
auxiliary electrode with the measuring medium.
Metallic control shafts/pipes and other large-area metallic bodies
that reach into the measuring medium are, for example, ideal for use