Follow Our FB Page << CircleMedia.in >> for Daily Laughter. We Post Funny, Viral, Comedy Videos, Memes, Vines...


What standards are used for earthing of field instruments?



What standards are used for earthing of field instruments?..

Answer / sam

The internal screen is always floating at the instrument.
This means we just put some heat shrink on it to seal it and
then tie it off inside the instrument and just let it lie
there. The overall screen (braiding surrounding the cable
just below the pvc outside)will be in contact with the gland
once you have installed the gland. On the gland thread you
install a copper gland ring and a red IP washer, and the
gland then are attached to the instrument. From the gland
ring you use a six mm bolt and nut with copper washers to
attached a small diameter earth wire (about 4 to 6mm is
fine). This earth wire is then attached to the outside of
the instrument at the earth connection point on it's
housing. Every instrument will have this earth connector on
the outside of it's housing. From there you attached another
earth wire to the earth boss nearby. This boss is normally
just a piece of round bar about 40mm in diameter and about
30mm long and tapped in the middle that is welded to the
structure close by, specially for this earthing of the
instruments. Again it is better to use copper washers. If no
boss is available you can use some other point on the
structure as well like a stainless steel cable tray for
instance but the earth boss should really be part of the design.
On the other side of the instrument cable at the RTU the
internal screen in attached the instrumentation clean earth.
The dirty earth is used only for electrical equipment.
Good luck

Is This Answer Correct ?    5 Yes 4 No

Post New Answer

More Instrumentation Interview Questions

how to measure level under ground tank ? which type of transmitter very accuracy ?

3 Answers   Biocon,


How many types of Control Modes in process control, plz tell me all.....?

2 Answers  


what is the formula for calculating milliampere at different pressure points for eg 4-20 ma = 3-15 psi but if i have to check the ma at 4.6 ma?

4 Answers  


plz exlain the dcs system of ABB sympony hamnony

1 Answers  


TRANSDUSER MOSTLY CONVERT WHICH ENERGY INTO ENERGY ?

6 Answers   DVC,






1,why we use 4-20 ma output of all instrument qhy not use 0- 20, 2,what is the different between PLC & DCS. 3,how can we meaure maximum span of new flowmeter if not given any information.

4 Answers   Reliance,


How to convert ma to mv? Resistance 250 ohm is connected in series or Parallel?

3 Answers   ISRO,


why temperature transmitter is showing ambienttemp.but 21.5ma. alarm AO showing at the display &how to sloves this problem.

2 Answers  


what would be the minimum flow rate that we can measure on rotameter..?

0 Answers   TATA,


We have yokogawa cs3000 one fcs and 4 his. After download to his, showing successfully at es, but not transferred to his.

1 Answers   Shyam Steel,


State bernoulli’s application.

0 Answers  


What is safety barrier and how it is work

2 Answers   IOCL,






Categories
  • Civil Engineering Interview Questions Civil Engineering (5074)
  • Mechanical Engineering Interview Questions Mechanical Engineering (4444)
  • Electrical Engineering Interview Questions Electrical Engineering (16594)
  • Electronics Communications Interview Questions Electronics Communications (3915)
  • Chemical Engineering Interview Questions Chemical Engineering (1092)
  • Aeronautical Engineering Interview Questions Aeronautical Engineering (214)
  • Bio Engineering Interview Questions Bio Engineering (96)
  • Metallurgy Interview Questions Metallurgy (361)
  • Industrial Engineering Interview Questions Industrial Engineering (258)
  • Instrumentation Interview Questions Instrumentation (2986)
  • Automobile Engineering Interview Questions Automobile Engineering (332)
  • Mechatronics Engineering Interview Questions Mechatronics Engineering (97)
  • Marine Engineering Interview Questions Marine Engineering (123)
  • Power Plant Engineering Interview Questions Power Plant Engineering (170)
  • Textile Engineering Interview Questions Textile Engineering (575)
  • Production Engineering Interview Questions Production Engineering (0)
  • Satellite Systems Engineering Interview Questions Satellite Systems Engineering (106)
  • Engineering AllOther Interview Questions Engineering AllOther (1377)