Grounded thermouple in intrinsically safe circuits

[hamidzar]

Hi Guys,

Do you have an idea how to install a grounded thermocouple in an intrinsically safe circuits, IEC60079-14 provides some guidelines, but I am not sure what the real requirements are , could they be used in EPL "Ga" when they are connected to Rosemount 3144P temperature transmitter? is Galvanic isolation on the transmitter a must or 500Vrms isolation would be enough?

Thank you all in advance,

[carl_e]

My charts tell me EPL GA is zone (gas) 0. Device Category 1G is for Zone 0.

Rosemount's 3144P Reference Manual 00809-0100-4021, Rev GB states certification ATEX zone 0 certification 1G:
I1 ATEX Intrinsic Safety (Zone 0)
Certificate Number: BAS01ATEX1431X
ATEX Category Marking II 1 G
Ex ia IIC T6 (Tamb = –60 to 50 °C)
Ex ia IIC T5 (Tamb = –60 to 75 °C)
Special Conditions for Safe Use (x):
The transmitter is not capable of withstanding the 500 V insulation test as defined in Clause 6.3.12 of EN60079-11. This condition must be taken into account during installation.

Quick Start Guide, 00825-0100-4021, rev. HA, February 2013 has wiring for grounded and ungrounded thermocouples.

You still need a barrier/isolator for that is suitable for the transmitter's entity parameters.

[hasanbarim]

In IS applications , For fast response application grounded thermocouples (Ex e or d) should be used with a Eex ia transmitter and IS isolator at the system side.