Sutron Corporation 8310 & 7310 Users Manual 8800-1125Rev. 2.7 (BETA) 4/16/2014 pg. 188
Cabling
Many sites have serious problems because of bad cabling. The following points should be
considered as you plan and install your cabling:
1. Keep cable length to a minimum. The shorter the run, the less chance of signal degredation.
2. Use shielded cable especially if the run is greater than 75 feet. The additional cost is minimal
compared to the cost of logging bad data.
3. Bury the cable when possible. Make sure, however, that the cable used is rated for direct
underground burial. If not, conduit should be used to protect the wires.
4. Strip and tin ( tinning is another term for soldering.)the ends of the wires that connect to the
8310. If the ends are not tinned, the wires might frey causing a bad connection and potential
signal loss.
5. Finally, the most common mistake made when connecting to the 8310 occurs when the
insulation is securred instead of the bare wire rusulting in a bad connection.
Surge and Lightning Protection
A major factor in keeping a site fully operational for extended periods of time is proper
grounding. Static electricity and other transients from nearby storms or high voltage power lines
can cause a variety of problems in the 8310 if the site is not grounded properly. Good grounding
is the most important way to protect a site from damage caused by transients and to insure its
long-term operation. The guidelines listed should be followed when an installation is
performed.
1. Use long ground rods. The idea behind earth grounding is to drive the rods far enough into
the ground so the metal comes in contact with the grounds' own moisture. Because of this,
exact lenghts of the rods may vary, therefore you must have a good idea of current conditions
such as precipitation amounts and ground moisture levels to make the best judgement on the
length of the rods. As a general rule of thumb, the longer the better.
2. Use more than one rod. In some instances it may be necessary to create a grounding array of
up to four rods all of which are tied together by a heavy gage copper wire (10-12 AWG).
Remember to not compromise length for numbers. It is far better to have one 8 ft. grounding
rod than four 2 ft.rods.
3. After tying the rods together with copper cable, connect another piece of the copper wire to a
rod and bring it inside to be connected to the logger and sensors if necessary. There is a ground
lug located on the lower left hand corner of the 8310 which can be used to connect to. When
bringing the wire into the gage house or Nema Enclosure, try to keep bends in the wire to a
minimum since lightning tends to follow a straight pathway.
4. At stream gaging stations, do not solely ground to the stilling well. It would appear logical
that the best ground one could have would be the river or stream at the site, however, when a
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