KROHNE BM 70 M - Manual (Page 97)

BM 70M-EEx/ BM 70Mi-EEx 11
Terminal compartment in EEx e or EEx ei type of protection
Permissible as cable entries and blanking plugs are only parts certified to EN 50 019. The cable
clamping area for the supplied cable entries measures 9 – 16 mm. Use cables with appropriate
diameter or approved cable entries with matched clamping area in accordance with their test
certificate.
Terminal compartment in EEx d or EEx di type of protection
The cables can basically be routed into the flameproof terminal compartment in one of two ways.
Direct entry of the connecting cables by way of flameproof cable glands into the flameproof
terminal compartment using the certified NPT ½“ adapters fitted by the device manufacturer, or
using flameproof glands with separate test certificate to EN 50 018. Tight fitting of the adapters in
the housing to be ensured, especially after detaching from piping.
Direct entry of the connecting cables by way of conduits into the flameproof terminal
compartment of the device requires, after the conduit has been screwed in, a flameproof joint in
accordance with ISO 965 / DIN 13 with a minimum of five full turns depth of engagement. A
suitable stopping box to be provided within 450 mm of the entry into the terminal compartment.
Installation of the conduit must be carried out in conformity with its separate test certificate.
Generally, a certified NPT ½“ adapter provided by the device manufacturer, or an EN 50018
certified adapter is required between the “PG” thread (heavy-gauge conduit thread) of the terminal
compartment and the conduit thread.
5.2.2 Connecting cables
The power cables for the non-intrinsically safe power circuits, and for the non-intrinsically or
intrinsically safe I/O circuits shall be selected in keeping with the valid installation standard
(e.g. EN 60079-14).
Where elevated product temperatures are concerned (see also Section 3.3.2 “Temperature
classes“), use heat-resistant cables with a continuous service temperature of
≥
80°C in conformity
with the type test certificate.
5.2.3 Connection of power and I/O functions
• Before connecting or disconnecting the electrical interconnecting cables of the device, make
sure that all cables leading to the signal converter are isolated from the ground (reference
potential) of the hazardous area. This also applies to safety conductors (PE) and equipotential
bonding conductors (PA).
• All cores and shields of the power cables not safety-connected to the equipotential bonding
system for the hazardous area should be carefully insulated from each other and from ground
(test voltage 500V
rms
for conductors of intrinsically safe cables, test voltage 1500V
rms
for
conductors of non-intrinsically safe cables).
•
Connect all shields by the shortest possible route to the press-fitted U-clamp terminal (FE) in
the terminal compartment. If shields are to be grounded at both ends (e.g. for EMC reasons),
adequate equipotential bonding is required between the two shield ends to avoid
unacceptable circulating currents.
• Independent of the type of power supply, the device must be incorporated in the equipotential
bonding system of the hazardous area. This can be done by way of an appropriately
conductive connection between the device flange system and the tank. If connection to the
equipotential bonding system is to be made via a separate conductor, this must be connected
to the outer press-fitted U-clamp terminal on the signal converter flange.
•
In the case of device versions with intrinsically safe I/O functions (BM 70 Mi -EEx), only certified
intrinsically safe equipment with the maximum values (see Section 3.1.4 and type test certificate)
may be connected to the power terminals marked as being intrinsically safe. This requirement
also applies when the device is not operated in the hazardous area!