KROHNE H250 M40 ATEX II2D Ex t-II2G Ex d EN - Manual (Page 14)

4
ELECTRICAL CONNECTIONS
14
H250 M40
www.krohne.com 07/2012 - 4002069601 - MA H250/M40-Ex-II2GD-AD R01
Electrical connections
4.1 General notes
Rated values for insulation
• The insulation of the H.../..../M40 - Ex variable area flowmeter is rated in compliance with
IEC 60 664-1. The following rating parameters are taken into account:
• Overvoltage category for signal and instrument loops: II
• Pollution degree of the insulation: 2
Terminal compartment
The electrical connections for the power supply and I/O functions are made in the electronics
compartment of the signal converter. The protection type of the electronics compartment is "d"
and/or "t". Unused openings are to be closed in compliance with EN 60079-1 and/or EN 60079-
31. The cables may enter the electronics compartment in two different ways.
• Direct entry of the connecting cables by way of approved flameproof cable glands (M20x1.5)
into the flameproof terminal compartment (V ≤ 2000cm³). The cable glands require a
separate test certificate in accordance with EN 60079-1. Observe the requirements of the test
certificate for the cable glands.
• Direct entry of the connecting cables by way of conduits into the flameproof enclosed
terminal compartment of the device. Once the conduit has been screwed in, it must form a
flameproof joint with the housing with a minimum thread length of 8 mm. A suitable
mechanical stopping box must be provided in accordance with installation provisions. The
conduit must be installed in compliance with its separate test certificate.
• Direct entry of the connecting cables by way of permitted dustproof cable glands (M20x1.5 )
into the dustproof terminal compartment (V ≤ 2000cm³). The cable glands require a separate
test certificate in accordance with EN 60079-1. Observe the requirements of the test
certificate for the cable glands.
Connecting cables
The connecting cables should be selected according to the applicable installation standards (e.g.
EN 60079-14 / VDE 0165) and the maximum operating temperature.
• The connecting cables must be fixed and laid so they are sufficiently protected against
damage.
• Lay cables so as to ensure that there is sufficient distance between surfaces of the
measuring unit and the connecting cable.
• Supplied blind plugs / cable entries guarantee protection against foreign bodies and water
(protection category) IP66 / 67 according to EN 60529 in the temperature range
• The outer diameter of the connecting cable must be within the sealing range of the cable
entry (7...12 mm / 0.27...0.47").
• Unused cable entries are to be closed in accordance with EN 60079-1 and/or EN 60079-31
(>IP66 / 67).
Ensure that the seals and cut seals are tight.
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