Isolating Equipment From The Pipeline; Meter Runs Without Cathodic Protection - Emerson ControlWave EFM 4710A Instruction Manual

For applications employing equipment that communicates over telephone lines, a lightning
arrester Must Be provided. For indoor equipment the lightning arrester must be installed
at the point where the communication line enters the building as shown in Figure 3-6. The
ground terminal of this arrester must connect to a ground rod and/or a buried ground bed.
Gas lines also require special grounding considerations. If a gas meter run includes a
thermocouple or RTD sensor installed in a thermowell, the well (not the sensor) must be
connected to a gas discharge-type lightning arrester as shown in Figure 3-7. A copper braid,
brazed to the thermal well, is dressed into a smooth curve and connected to the arrester as
shown. The curve is necessary to minimize arcing caused by lightning strikes or high static
surges. The path from the lightning arrester to the ground bed should also be smooth and
free from sharp bends for the same reason.
Figure 3-7 - Grounding of Thermometer Well in Gas Line

3.4 ISOLATING EQUIPMENT FROM THE PIPELINE

3.4.1 Meter Runs Without Cathodic Protection

ControlWave EFM/GFC/XFC's may be mounted directly on the pipeline or remotely on a
vertical stand-alone two-inch pipe (see Figure 3-8). The Earth Ground Cable is to run
between the ControlWave EFM/GFC/XFC's Ground Lug and Earth Ground (Rod or Bed)
even though the ControlWave EFM/GFC/XFC's Multivariable Transducer may be
Section 3 - Grounding & Isolation Page 3-7 S1400CW