Page 223 - Electromechanical Devices and Components Illustrated Sourcebook

Chapter 10 Wire and Conductors 185

Nut
Washer
Drilled Bolt
W/Potted Bare Wires
Threaded Stud

BNC
Connector
Head Piece
Type F Connector
Ceramic Insulator

Connector Pin
Drilled Bolt
W/Potted
Insulated Wires

Figure 10-56 Electrical Bulk Head Fittings

Figure 10-56 shows a few commercial bulk head fittings.
Many different types of connectors are available in bulk head
configurations. These types of connectors are easy to install,
provide an excellent seal, and are inexpensive. For soldered
feedthroughs a bolt is drilled and wires are potted into the
hole. Drilled bolt feedthrough may be constructed with insu-
lated or uninsulated wires.
Cable Clamp
Low-differential pressure feedthroughs may use insulated
Cable wires, while high-pressure feedthroughs typically use bare,
solid wires. Figure 10-57 shows a couple of standard high-
Figure 10-54 Stacked Hanging, High-Voltage Insulators
pressure feedthroughs. The body is a through-drilled NPT
(national pipe thread) bull plug. The wires are placed into the
body and the through hole is flooded with a two-part, chemical
Antenna and guy wires must be isolated from ground set potting material.
and/or power lines. Antenna or egg insulators are commonly
used for this application. Figure 10-55 shows two popular guy
wire insulators. The upper illustration is designed for high-
Drilled NPT Bull Plugs
weight antennas and guy wires. The illustration at the bottom
is for lighter weight loads such as amateur radio antennas.

Insulated
Wires
Heavy Duty

Bare Wires
Light Duty
Figure 10-55 Antenna or Guy Wire Insulators Figure 10-57 High-Pressure Feedthroughs

Electrical Feedthroughs Building a high-pressure feedthrough is not a difficult
proposition. Figure 10-58 can be used as a guide for con-
Various applications require that electrical signals pass structing high-pressure feedthroughs. An NPT bull plug is
through a hard barrier, such as a panel in a sealed cabinet or drilled through on the center of its axis. A pattern of holes are
the wall of a pressure vessel. Bulk head fittings or feedthroughs drilled into a polytetrafluoroethylene (PTFE) plastic plate, which
are typically used for these applications. are spaced to align the necessary conductors. The conductors