Page 99 - Mechanical Engineers' Handbook (Volume 2)

88 Bridge Transducers

Figure 12 Color code and wiring designation, single-arm bridge. (Courtesy of Western Regional Strain
Gage Committee.)

Table 4 Multiconductor Strain Gage Cable Guideline, Western Regional Strain Gage Committee
A need exists for low-millivolt signal levels to be transmitted by better quality multiple conductor
cables of considerable length.
I. Conductors Three through eight twisted, stranded conductors of tinned copper per
ASTM-B-174, AWG 20-16/32, or AWG 18-16/30
II. Color code Jacket: orange, grey, white, or black
Conductors: Per ISA-S37.3, ANSI-MC6.2-1975, and WRSGC/SESA
5-6-1960
III. Insulation Superior to the PVC materials currently in use. The dielectric material should
be nonhygroscopic and approach zero water absorption and zero water
permeability. Target jacket thickness of .016 in. or less and conductor
insulation of .012 in. or less. Target resistance values should be constant as
practical humid and wet environments and as high as possible (target value
of 500 per 1000 ft). The breakdown level of the dielectric materials shall
be greater than 150 V dc.
IV. Construction The cable shield shall be aluminized polyester tape with 100% coverage of all
conductors. A 22-AWG drain wire shall be in intimate contact with the
shield throughout the entire cable length. The cable shall have as a small a
diameter as practical and be flexible enough to have a bend radius less than
six cable diameters. Overall cable strength sufficiently high to be pulled
through conduits.
Courtesy of Society for Experimental Mechanics.