Guidelines for safe use in hazardous conditions - MGP262 - MGP261

MGP260 Series Installation and Safety Guide

Document code
English (United States)
Document type
User guide

Process connection and partition wall

Figure 1. MGP260 Ga/Gb division
The part outside of the process (up until to the NPT 1.5" connection thread) complies with the Gb Equipment Protection Level (EPL).

The part inside the process (starting from the NPT 1.5" thread) complies with the Ga EPL.

The partition wall is made of stainless steel, sapphire glass, and silicone adhesive. The stress limit temperature range of the silicone adhesive is -40 … +60 °C (-40 ... +140 °F).

Warning While installing or uninstalling the device, there is a risk of flammable gas release or flame entrance.

Wiring requirements

  • The wiring of the optional intrinsically safe (Ex ia) external pressure or temperature sensor input terminal must be kept separate from the analog output, power supply input, and RS-485 wiring.
    • See the installation overview and installation instructions for more information.
  • The cable glands and cables used for wiring the device must not impair the Ex protection.
    • US/CAN: The cables used for wiring must have a flammability rating of UL 2556 VW-1 or equivalent.
    • Unused lead-throughs must be sealed using Ex compliant plugs.
  • See Table 1 for screw terminal requirements.
  • Use an 18 … 30 VDC power supply with the probe.
    • Permitted supply short-circuit current (Ik): 50 A.
    • US/CAN: only use a UL listed 18 … 30 VDC (min. 6 W) power supply. The power supply must be UL/CSA 60950-1 certified.
    • MGP260 analog outputs must be externally powered.
CAUTION Connect only de-energized wires. Never switch on the power supply input before completing the wiring and closing the connection box.
Table 1. Screw terminal wiring requirements
Property Specification
Connection torque 0.5 Nm ... 0.6 Nm
Wire cross section / connection capacity (solid and flexible) 0.2 mm2 ... 2.5 mm2 (AWG 24 ... 12)
Stripping length 7 mm (0.27 in)

Intrinsic safety

The overvoltage category of MGP260 series probes is I (non-mains equipment), as defined in IEC 60664-1.

MGP260 probes are in conformance with the IEC 60079-11 dielectric strength requirement. For the intrinsic safe IIB output parameters, see Table 2.

Table 2. Intrinsic safe IIB output parameters
Parameter Value
Uo 25.2 V
Io 78 mA
Po 0.5 W
Um 40 V
Co 820 nF
Lo 20 mH
The parameters listed in Table 2 apply when one of the two conditions below is given:
  • the total Li of the external circuit (excluding the cable) is < 1% of the Lo value; or
  • the total Ci of the external circuit (excluding the cable) is < 1% of the Co value.
The parameters are reduced to 50% when both of the two conditions below are given:
  • the total Li of the external circuit (excluding the cable) is ≥1% of the Lo value; and
  • the total Ci of the external circuit (excluding the cable) is ≥1% of the Co value.

Note: the reduced capacitance of the external circuit (including cable) shall not be greater than 1μF for Groups I, IIA, IIB & IIIC, and 600nF for Group IIC.

The values of Lo and Co determined by this method shall not be exceeded by the sum of all of the Li plus cable inductances in the circuit and the sum of all of Ci plus cable capacitances, respectively.

Connecting probe to Insight PC software

The Insight PC software connection cable must only be used outside the explosion hazardous area. Remove the probe from the process for configuration, and use only the Vaisala accessory PC connection cable to connect the probe to Insight.


The probe filter is the only user-replaceable part in MGP260 probes. For other maintenance requirements, contact Vaisala.

CAUTION Live maintenance is not allowed.
The content in this chapter is maintained in the following separately tracked document:
Document ID: M212501EN Revision: A (30 Jun 2020)