What standards are used for earthing of field instruments?
- 1 Answers
- 10324 Views
- I also Faced
- E-Mail Answers
Answer Posted / 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 View All Answers
List three types Level Gauges with their working principles
What is Positive Calibration and Negative Calibration?
for oil & gas industries which zone is normally preferred? why? give its example?
what is exact time to study dcs and plc cources
How to do gas analysers calibration in AUTO and Manually by using zero and span gas?
what is cold loop? difference between hot and cold loop?
what is the reset offset and control system in instrumentation
wich is coming the first HAZOP OR SIL
how does we calibrate a square root flow transmitter ,give an example and explain it step by step like range calculation , calibration hook up series connection , zero check , and how to apply pressure , and if not geting proportional output then what should we do ?
Instrument QA/Qc what is the project quality plan?conduit inspection RFI. which documents attache with package?
If fire would be inside the plant which fire detector is to detected the fire.
what is difference between fork type and capacitance type level switch. where it is using
How to Calibrate Interface Level Troll in field
How to calibrate capillary type level transmitter
How works weighfeeders in cement industry? what is the working principle?
