TURTLE
TOUGH
®
13
Choosing the correct waterproofing option
Recommendations for Inline, Immersion and Submersible Installations
Turtle Tough Inline Twist Lock sensors and immersion sensors are NOT intended to have rain or other continuous
forms of water on the back of the cable. In this case, a shorting can result in a variety of anomalous failure modes.
** IF SUCH ANOMALOUS FAILURE MODES RELATED TO THIS OCCUR THIS IS CONSIDERED AN IMPROPER
INSTALLATION ISSUE AND THUS NOT COVERED UNDER THE STANDARD TURTLETOUGH WARRANTY **
The sealing on the back of a twist lock and immersion sensors is water-resistant, but not waterproof. The standard
default isolation on the back of a sensor is a strain relief grommet. This allows for the sensor to be somewhat
moved and for some minor water exposure without causing sensor failure. For more aggressive water exposure to
the back of the sensor, additional precautions must be taken.
Indoor Inline Use
If a standard sensor (such as our immersion or Twist Lock sensor series) is used for inline installations only (no
immersion or submersible use is planned) then no special precautions are required if it is for indoor use. This
assumes that the back of the sensor will not be exposed to corrosive gas present and/or the plant will not cause
any process media to get onto the back of the sensor, nor give it significant water exposure by washing down the
area.
Outdoor Inline Use
If a standard sensor (such as an immersion or Twist Lock sensor series) is used for inline installations only (no
immersion or submersible use is planned) then there generally ARE special precautions required for outdoor
inline use. The most common is to seal the back end of the sensor in conduit to isolate the back end of the sen-
sor. The most common approach so to use sufficient TEFLON tape and an FNPT coupling to create this back
sensor seal, and then either a rigid or flexible conduit back to the transmitter where the plugs are terminated for
cable isolation. This creates a barrier that makes the sensor suitable for conditions where rain and other outdoor
elements could damage the seal on the back of the sensor. Specifically, this can prevent water from attacking
along the sensor cable and causing internal shorting to solder joins inside the unit itself.
Another approach for sealing the back of the sensor if there will be significant water exposure is to add a wa-
terproofing option. In general, for such cases, just the least expensive cable protection option is sufficient, with
a 3/8"X1/2" vinyl tubing properly installed. The cable protection option has a slight surcharge for extended cable
lengths. In some cases, the more robust Standard waterproofing option can also be used to fulfil this purpose.
Unfortunately, waterproofing options cannot be added once a sensor has been fabricated but rather must be
installed at the time of manufacture.
Immersion Use
Immersion use is defined as when the sensor is immersed into the process media, but the entire sensor is not
submersed. This means that the back of the sensor is NOT completely below the process media level. Immersion
installations always require the back of the sensor/waterproofing to be sealed with a mating 1" FNPT coupling
and the cable run in conduit. The cable protection or standard waterproofing options can be added if desired/
required to make the sensor life better even for such immersion installations. It is possible to use the standard
immersion or Twist Lock sensor for immersion use without adding a waterproofing option if VERY GOOD care is
taken to seal the back of the sensor with a coupling and properly running the cable in conduit back to the transmitter.
