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1.0 APPLICATIONS
The Model 252C Ground Strap Tester shown in Figure 1.0-1 is a precision wall or bench
mounted test instrument that can test virtually all types of personnel grounding
cable/wrist strap and heel strap assemblies. The instrument measures ESD grounding
straps with a nominal resistance of 1 MegOhm. It can be used to test a strap assembly
alone or a complete cable/wrist strap system while on the wrist of the user. The
grounded power supply used in the Model 252C enables heel straps attached to
personnel to be tested without any additional connections when used in conjunction with
grounded floor systems (RTG <10
5
Ohms).
Figure 1.0-1: Model 252C Ground Strap Tester
2.0 EQUIPMENT
DESCRIPTION
The Model 252C Ground Strap Tester is housed in a heavy-duty plastic housing
measuring 4.75” x 4.75” x 2” (121x121x51mm). The removable top cover is attached to
the base unit by four captive screws. A silicon rubber gasket provides additional
protection from outside contamination. The system is AC powered and incorporates a
built-in transformer coupled regulated power supply protected by a ¼ amp fuse. Either
115 or 230VAC operation can be specified. A heavy-duty 3-wire, 18 gauge, 8 foot long
power cord is provided.
3.0 SET-UP
The Model 252C is designed to be permanently mounted to a wall, but also may be
mounted to a workbench or be free standing. The unit contains four mounting holes that
will accept up to a #8 (4mm) size screw (not supplied unless a specific type is specified
and ordered separately) The type of screw and its length will depend upon the surface
to which the unit is mounted. For wood walls, a 3/4” (20mm) long wood screw is
recommended. For plaster or dry wall, either a toggle bolt or a plastic anchor should be
used. For concrete walls, a plastic or lead anchor is recommended.
