KROHNE H250 M40 NEPSI Ex d-Ex t - Manual (Page 13)

ELECTRICAL CONNECTIONS
4
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H250 M40
www.krohne.com 06/2013 - 4002868601 MA H250-M40-NEPSI-Ex-d-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 DIP. Unused openings are to be closed in compliance with applicable standards. 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. 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. 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 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 IEC 529 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 applicable standards (>IP66 / 67).
Ensure that the seals and cut seals are tight.
CAUTION!
The IP protection category of the signal converter housing is largely determined by the cable
gland used and the installation.
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