Gfd Specs

2.5 kVA output 115 VAC, 60 Hz 20-amp max output current 10-msec max shutdown time

CAUTION Certain types of electrical equipment will not operate with the GFD or the GFD may damage the equipment connected to it. Qualified electronics technicians must review circuit diagrams before using electrical devices with the GFD.

Figure 2-10 2.5-kVA ground fault detector.

Some electrically operated equipment such as ROVs, video equipment, and communications gear may have built-in ground fault detectors. Using this equipment with the GFD may cause both circuits to malfunction and not provide shock protection. A qualified elec tronics person should review the system for potential problems. Underwater Electric Field Detector. The Underwater Electric Field Detector (UEFD) (Figure 2-11) was designed to be carried by the diver. The UEFD senses a voltage across three electrodes located in the tip of the probe and provides a warning when the diver enters the presence of an electrical field.

The UEFD provides the diver with a method of surveying underwater equipment and facilities to locate potential electrical hazards. The probe can also be used to test the water before the diver enters.

WARNING The UEFD does not protect the diver after he swims into a dangerous electrical field.

Sensing probe .Front collar





Figure 2-11. Underwater electric field detector.


Figure 2-11. Underwater electric field detector.

The unit is calibrated to detect and warn the diver of a weak field and a strong Held as follows:

• Weak field signal (0.1 V/ft) will warn the diver that an electric field is present and to proceed with caution.

• Strong field signal (0.2 V/ft) will warn the diver he is swimming into a dangerous electric field whereupon he should swim away or get out of the water. A field strength of 0.2 V/ft is not fatal but will be physically perceptible and may be uncomfortable.

2.2.6 Stud Driver

The stud driver shown in Figure 2-12 is a power velocity tool which drives fasten-

Figure 2-12 Underwater version of the Ranset stud driver currently approved for Navy use.

ers using a 38-caliber cartridge. Factory pre-loaded, waterproof barrels are used to drive fasteners. Both threaded (stud) and headed (nail) fasteners are available. The tool can be used to attach padeyes, zincs, patches, and anchoring points to metal and concrete.

The underwater version of the stud driver is on the Navy ANU list and is capable of driving fasteners into steel up to 1 inch thick or concrete to any thickness. Fasteners are color coded to provide different load levels. Because of the potential for injury to personnel, NAVSEA OOC requires operator training and certification prior to tool use.

WARNING An operator's certification card must be obtained before operating the tool.

WARNING Never fire into hard or brittle materials such as cast iron, tile, glass, or rock. These materials can shatter causing sharp fragments and/or the fastener to fly freely. Concrete. Table 2-5 provides some examples of the holding power of fasteners in concrete materials. As a fastener is driven into concrete, it displaces its embedded volume and compresses the area of concrete directly surrounding the fastener shank. In addition, sufficient heat is generated during the driving process to cause fusion of small masonry particles with the fastener shank. The bond developed by the compressed concrete and fusion creates the fastener's holding power.

Holding Power The Fastener

Figure 2-12 Underwater version of the Ranset stud driver currently approved for Navy use.

Table 2-5. Allowable Working Values for Low Velocity Fasteners in Stone Aggregate Concrete (lb)

Catalog Number Series

Shank Diam (in.)

Penetration (in.)

Min. Edge Distance (in.)

Min. Spacing (in.)

Concrete Compressive Strength (psi)










3300 Series Drive Pins

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