YSI IQ SensorNet 2020 XT Terminal - Manual (Page 41)

System 2020 XT USB Installation
3 - 11 ba76019e01 12/2012
2 The SNCIQ or SNCIQ-UG cable material must be used exclusively.
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. We strongly recommend not to use any other cables,
which normally have a considerably lower shielding wire cross-
section.
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
in the grounding of the mounting construction.
This creates a set path for the main surge. As a result it is possible
to avoid the surge being discharged via the IQ IQ S
ENSOR N ET cable
and via the valuable sensors in the measuring medium.
4 The contacts of the MIQ modules always have to be protected with
the respective contact covers when they are not used by terminal
components. The contact covers improve the insulation against
electric fields of a thunderstorm by enlarging air gaps and creepage
distances.
5 We recommend to install a metal or nonmetal sun shield at each
open air location of MIQ modules. Sun shields protect the electric
field lines in the area of the MIQ module through an advantageous
development of the electrical field lines in the area of the MIQ
module and promote the dissipation of the surge via the mounting
construction.
6 The line voltage that supports the measuring system must
correspond to overvoltage category II. Normally this is ensured by
the public operators of the supply network systems. In company-
owned networks, e.g. in all power supply systems owned by
wastewater treatment plants, this must be kept separate by a
potential equalization and asurge protection system for the plant.