The common testing items for Fiber Optic Splice Closure are: Tensile strength test: check the maximum tensile force that the box body can withstand and whether it meets the requirements. Waterproof test: test the protection level of the junction box, such as whether. Sealing methods for fiber optic splice closures are critical for the following reasons. Effective sealing ensures the longevity and reliability of the network. In. Bonding and grounding: Roxtec BGTM provides solutions for termination of conduits, armored and metal clad cables in control cabinets and junction boxes.