The following are power cable and connector safety precautions that should be observed:
a. All parts of the cables that are intended to be submerged shall be fully insulated and watertight. This can not be overstated.
b. Inspect cables and cable connections for damaged insulation before starting operations. Defects in the cable must be repaired or the cable replaced before starting operations.
c. All connections shall be made tight and thoroughly insulated by wrapping in rubber tape, applying a layer of scotch cote, then wrapping with electrical tape. This will prevent current loss at the connections. Cables which produce bubbles during operation should be replaced. The bubbles indicate that current is being lost through the porous insulation.
d. Use only welding cables that are a minimum of 2/0 extra flexible. An exception is the electrode holder lead, which can be 1/0. The 1/0 lead is more flexible and will aid the diver in maneuvering the electrode holder. The cable must conform to the applicable requirements of Military Specification MIL-C-915. Cables must be capable of handling the maximum current requirements of the intended work.
e. Do not use excessive lengths of cable with large sections stored on deck. When working in deep water, a strain relief should be provided across the connections to support cable weight.
f. When connecting lengths of cable, use connectors which have a current carrying capacity that is equivalent to the cable being used.
g. Ensure that the 1/0 stinger lead between the electrode holder and the welding lead is defect-free. The cable connection coupling the stinger lead to the 2/0 welding lead should be thoroughly insulated with a layer of scotch cote, wrapped in rubber tape, insulated with an additional layer of scotch cote, then finally wrapped with electrical tape or heat-shrink tubing. This will afford added protection for the diver.
h. Secure the ground clamp as close to the work-site as possible, preferably in the forward line of vision. The diver must face the ground when welding or cutting. A good rule-of-thumb to remember is: NEVER TURN YOUR BACK TO THE GROUND WHEN THE POWER IS ON.
i. Keep additional power cables such as underwater light cables and welding leads separated.
j. Cables should be strung overhead if they are to be run for long distances. If this is not practicable and they must be laid on deck, they must be protected and arranged to prevent interference with safe passage of personnel.
k. When portable lighting is used, it should be clamped or fully secured in position and not hand held. The portable lighting power cords must be kept clear of the welding leads and work area. Additionally, a ground-fault detector/interrupter (GFD/I) must be incorporated in the circuit.
l. Cables in storage should be kept dry and free of grease and oil, which cause premature breakdown of the insulation.
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