Tether connections are the weak link in the power and communications required by the ROV. Each connection should be checked for corrosion or debris and lubricated with a silicone based grease before mating. The strain relief is critical to carry the load. Without the strain relief, the connections are likely to separate and if it is not installed properly, the connection can fail. Make sure that after the strain relief is connected there is no load on the connection when the tether is tugged in different directions.