Wiring Procedure; Grounding - ABB 266 DDS Operating Instruction

Pressure transmitters
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2 6 6 D D S H A R T | P R E S S U R E T R A N S M I T T E R S | O I/ 2 6 6 D D S - E N R E V. A

Wiring procedure

Follow these steps to wire the transmitter:
• Remove the temporary plastic cap from one of the two electrical connection ports located at both sides in the upper part of
the transmitter housing.
• These connection ports may have a 1/2 inch internal NPT-F or M20 threads. Various adaptors and bushings can be fitted to
these threads to comply with plant wiring (conduit) standards.
• Remove the housing cover of the "field terminals" side. See the indication on housing. In an Explosion-Proof/Flame-Proof
installation, do not remove the transmitter covers when power is applied to the unit.
• Run the cable through the cable gland and the open port.
• Connect the positive lead to the + terminal, and the negative lead to the – terminal.
• Plug and seal the electrical ports. Make sure that when the installation has been completed, the electrical ports are properly
sealed against entry of rain and/or corrosive vapors and gases.
WARNING - GENERAL RISKS
Cable and cable gland must be in accordance with the intended type of protection (e.g. intrinsically safe) and degree of
protection (e.g. IP6x according to IEC EN 60529 or NEMA 4x). See also the addendum for "EX SAFETY" ASPECTS AND "IP"
PROTECTION.
• If applicable, install wiring with a drip loop. Arrange the drip loop so the bottom is lower than the conduit connections and the
transmitter housing.
• Before reassembling covers, the integrity of the cover O-rings must be checked. If damaged they must be replaced with an
original spare part. A slight grease layer should be applied for proper lubrication.
• Put back the housing cover, turn it to seat O-ring into the housing and then continue to hand tighten until the cover contacts
the housing metal-to-metal. In Ex-d (Explosion Proof) installation, lock the cover rotation by turning the set nut (use the 2mm
Allen key supplied with the instrument).

Grounding

Pressure transmitter housing should be grounded or earthed in accordance with national and local electrical codes. Ground
connection is mandatory for surge protector equipped devices in order to ensure proper functioning.
Protective grounding terminals (PE) are available outside and/or inside the housing of the transmitter. Both ground terminals are
electrically connected and it up to the user to decide which one to use. The most effective transmitter case grounding method
is direct connection to earth ground with impedance equal or less of 5 ohm.
Figure 15 - Ground connection on transmitter housing
Surge protector equipped terminal block (optional)
The pressure transmitter housing with surge protector (code S2) inside the terminal board must be connected using the grounding
terminal (PE), by means of a short connection with the equipotential bonding. Equipotential bonding conductor must to have
4.00mm2 of maximum cross-section.
IMPORTANT
Test voltage withstand capability can no longer be ensured when this protective circuit is used.
17

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