Section 3 Mechanical Installation & Lightning Protection
26 FT722 & FT742 (RS485) – FF & PM Sensors – User Manual
Figure 17: Pipe Mount Sensor
The system ensures that the base of the sensor and connector/cable are sealed inside the pipe and adaptor. This
helps to protect against environmental degradation, as well as against the effects of indirect lightning strikes. The
FT028 O-ring (see location in Figure 17) is fitted to provide protection to the grounding surface and additional
protection for the connector.
The adapter can be secured tightly to the pipe using 4x M8 bolts. The sensor is secured to the adapter using a
spring clip and 3 more M8 bolts (supplied with the pipe mount adaptor, part number FT090). The adaptor includes
an alignment notch that allows repeatable and accurate orientation. The adapter and spring clip are made from
LM25/LM5 series aluminium-magnesium alloy and 5052/5454 grade ‘A’ aluminium respectively. The M8 bolts
have a hot-dip galvanised steel finish.
The vertical pipe should be made of an appropriate grade aluminium (aluminium is preferred as it provides
superior thermal conduction in icing conditions), or alternatively hot-dip galvanised steel. If galvanised steel is
selected, a minimum galvanising thickness of 50µm should be used to ensure the pipe has adequate long term
corrosion protection. The galvanising quality should conform to ASTM A123, Standard Specification for Zinc (Hot-
Dip Galvanised) Coatings on Iron & Steel Products.
The pipe should have a direct connection to ground and its top surface should be flat. A liberal amount of electrical
joint compound should be applied to this surface before the adaptor is fitted so that a long term low impedance
connection to ground is maintained. An example of this could be AFL Global’s Electrical Joint Compound # 2.
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