Reed -CONTROL RCS Betriebsanleitung Seite 14

To use the products safely, the following special characteristics must be
observed:
1. In order to dissipate electrostatic charges, the sliding tube and the power outlet require contact to the
earthed container.
Explanation: The non-electrically-conductive liquid would otherwise electrostatically charge the
sliding tube in a hazardous manner. Although no special requirements are imposed for contact to the
container, Point 2 must be observed.
2. Earth conductors that do not have the same electrostatic potential as the container must not be
installed in the container.
Explanation: High currents on earth connections in the area at risk of explosion cause significant
voltage drops that could act as a spark ignition source for the container wall via the connections for
the products. In the case of the «NP» models, the yellow-and-green cable is not connected to the
sliding tube in the container. Point 1 must be observed.
3. If the aluminium junction box is struck, ignitable sparks may be formed. This must be taken into
consideration if the junction box is installed in zone 0.
Explanation: In this context, ignitable sparks are hot, e.g. glowing, particles.
4. In order to prevent the junction box from being dangerously charged, it must not be wiped dry in
areas that are at risk of explosion due to gas group IIC.
Explanation: The junction box coating only meets the requirements for dusts and those of gas group
IIB. If hydrogen, acetylene or carbon disulphide are present in the surrounding atmosphere, the
junction box must not be charged.
5. The charging of products by means of highly effective processes must be excluded, i.e. fast-moving
particles along the junction box, as occur with pneumatically conveyed dust, flowing liquids and
droplets. Charges caused by free electrons or ions, for example, that appear during electrostatic
painting must also be excluded.
Explanation: This must only be taken into consideration on the earthed sliding tube with a floating
body, but not outside the container.
Taking into account the input data on intrinsic safety, the approved associated equipment must be inserted
ahead of the products to ensure a separation of intrinsically safe and not intrinsically safe. This restricts the
current and voltage values so that they are below the input data – even in the event of an error for ia. The
instructions for associated equipment must be observed. Safety barriers without galvanic isolation restrict
the voltage to its earth connection. This must be connected with the equipotential bonding of the area at
risk of explosion and there must be no differences in electrostatic potential to that of the container. The
same also applies to the earth connection and the cable shield for products that do not have «NP» in their
model name. Associated equipment with galvanic isolation is preferred. Its intrinsically safe connection
is isolated from the earth.
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