A stage pin connector, also known as a grounded stage pin (GSP), grounded pin connector (GPC) or theater paddle (TP), is a standard cable type for theatrical lighting in North America and in many countries in the theatre world.
Uses Stage pin connectors are generally used for conducting dimmed power from a dimmer to stage lighting instruments, although occasionally they can power other equipment.
Construction The first stage pin connectors had two cylindrical pins, one for line (hot) and one for neutral, arranged symmetrically in a rectangular housing. The housing was milled from a solid block of fiberglass or bakelite which may have been impregnated with asbestos for fire resistance, with a screw-on cover. Later connectors (including those currently manufactured) use molded plastic or machined phenolic resin laminate housings . These two-pin connectors were not polarized, and thus the line and neutral conductors could be exchanged depending on which way the connectors were mated. Two-pin connectors may still be found on some equipment and are often saved by electricians for wiring ungrounded fixtures (particularly practicals), though this may not be advisable from a safety standpoint. Modern stage pin connectors have incorporated a third pin for a safety ground connection and are commonly referred to as two pin and ground (2P&G) to distinguish them from their ungrounded two-pin predecessors. The ground pin is situated between the line and neutral pins and closer to the latter for 20 A connectors. This asymmetrical configuration effectively polarizes the connector ensuring that the line and neutral conductors are not exchanged in a properly wired installation. The ground pin is also longer than the other two, ensuring that the safety ground connection is made first when making a connection. All stage pin connectors have longitudinal slits in the male pins that allow for compression when inserted into the female sockets to increase friction and therefore the mechanical security of the connection. A special tool appropriately called a pin splitter may be used to expand this slit and spread the two halves of the pin to compensate for wear. A knife may be used to the same effect, but this technique risks both personal injury, damage to the connector, or ruining of the knife blade. For these reasons, a flat-head screwdriver is often used as an impromptu pin splitter. For some time Union Connector produced 2P&G connectors with a distinctive yellow cover that featured a locking tab in the ground pin that provided a positive mechanical lock to prevent accidental disengagement of the connectors. This design required special connectors on both the male and female side in order to work, meaning that all connectors in an installation would need to be replaced to see a real benefit to the locking feature. The expense of this proposition as well as the unpopularity of the connector itself among technicians led the locking feature to eventually be dropped, and locking connectors are no longer manufactured. The locking connectors that are still found occasionally in installations or spare parts bins are often referred to as "Union Connectors", though the Union Connector brand now features only standard non-locking stage pin connectors. Since their introduction, stage pin connectors have been available in 20 A, 30 A, 60 A, and 100 A varieties, with the higher-current connectors being not only far larger in size but also with a different pin configuration for ground, neutral and line. Care must be taken when repairing or building these larger connectors, because ground is on the outside pin and neutral is in the middle, with the far pin still being the line.
Cabling
Extension cables Most extension cables made with 20 A stage pin connectors use 12/3 type SOOW or SJOOW cable which has three individually insulated 12 awg (American Wire Gauge) stranded conductors inside a larger jacket. The internal insulation is usually colored black (for line), white (for neutral) and green(for ground). This cable configuration can safely handle the full 20 ampere rating of the connector. The designation SOOW or SJOOW refers to the cable's insulation construction and type. SJ— (300 volts, maximum) and S— (600 volts, maximum) are both "most severe" service cordage. This type of cable is very hard-wearing, resistant to oil and moisture, and resists the kinking that can result in internal conductors unlaying and twisting, which is a common problem with the SJTW cable often used in household-grade extension cords. However, older cable made using natural rubber is susceptible to dry-rotting, particularly with the heat generated by lighting equipment. This can cause the insulation to fail and expose or short circuit the conductors leading to shock or fire hazard if old cable is not inspected regularly and replaced as needed.
Multicircuit cable Some stage pin extension cables may be constructed from cable with six or more conductors. This cable can be fitted with multiple stage-pin connectors at either end enabling the single cable to carry multiple independent output channels of dimmed power. Each channel or circuit should have its own line, ground, and neutral conductor independent of the other circuits, though in some cases the ground or neutral lines may be shared among circuits. Alternatively, multicircuit cables may terminate in multicircuit (socapex) connectors which may in turn be mated to panel-mount multicircuit connectors on dimming equipment or distribution boxes, other multicircuit cables (to increase length), or break-in/break-out adapters to convert the multicircuit connection to a set of stage pin connections.
Equipment cabling The cables integrally connected to lighting instruments (often referred to as pigtails) may use 3-conductor SJOOW or SOOW cable or individual high-temperature wires inside of a fiberglass sleeve. In either case, the cable is often smaller gauge and sized to the current rating of the equipment it services.
… excerpt ends here. Continue reading the full article.
