In addition to the light source, another key part of streetlighting is a controlling mechanism which energizes the luminarie upon darkness and shuts it off around daybreak. Many people unfamiliar with the specifics concerning the operation of street lighting sometimes ask, "Does someone throw a switch somewhere and turn the street lights on?" In the earliest days of street lighting the answer to this question was "Yes". Back then it was standard practice for a central station operator to manually control street lighting circuits which were connected in series, commonly known as "arc light circuits". This method continued for many years and eventually was gradually superseded by automatic timers and photoelectric lighting controls. The latter were introduced in the early 1930s and were connected to relays and other regulating mechanisms that in turn operated strings of streetlights. At first, photoelectric lighting controls were very expensive. However, following World War II these controls became cheaper and therefore much more common. Manual operation of street lighting circuits did continue in some portions of the country as late as the 1960's.
Photoelectric lighting controls integral with their fixtures were indeed a great innovation in their day. These were glass bowl covered units containing a light sensing vacuum tube and numerous other electronic components. These "all-in-one" fixtures were introduced around 1950. They usually ran on either 120 or 240 volts and eliminated the necessity of a pilot wire and master high amperage photocontrol at the head of the circuit. Like the pioneer photoelectric controls introduced some 20 years earlier, these fixtures were expensive and therefore uncommon into the late 1950s. Of most interest are the ones that contained a mercury lamp ballast and photocontrol. These luminaries were also uncommon into the late 1950s due to their expense. However, they represented the most efficient method of street lighting at that time because of their state of the art light source and method of lighting control. Several of these fixtures are shown within this website.
Tube powered photoelectric lighting controls were re-engineered to a totally solid state design as early as 1956. An example is a Fisher Pierce model shown with a neon light indicator stem affixed to the top of the control. It has a manufacturing date of December 1956 and square aperture window, with a three-prong twist lock base configuration for its electrical connection, which is the same as utilized today. Fisher-Pierce introduced twist-lock, electronic controls with plastic covers during mid-1958. These units were considerably smaller and much less bulky than their tube-powered predecessors. This meant that luminaries could readily accommodate these more compact controls. The tube-powered units had a three-prong connector interface that was of a different physical configuration than the twist-lock design. By 1960 photoelectric lighting control and fixture manufacturers began to offer adapters that easily transformed the orientation of the tube-powered units' three prong positioning to that of the new twist-lock design. These were made for fixture and pole-mounted controls. Tube powered units were discontinued by the early 1960s since their solid-state twist-lock counterparts had become the industry standard by then. All twist lock controls manufactured by numerous companies had the same three-prong configuration in accordance to NEMA standards introduced in 1959.
Also, you will see several types of early tube-powered photoelectric lighting controls. As you will notice, some were intended for crossarm or pole mounting. Others were set into meter socket-type receptacles that usually were rated at 30 amperes, and these were also used for controlling strings of lights. These were more common in the years following World War II than individual controls integral with the luminarie. The physical configuration of the connections on these did not change through the years and these units are still made to this day, usually for replacements. Also shown are tube-powered controls removed from fixture heads and pole mounted controls made by Fisher Pierce and General Electric. Usually, the Fisher Pierce ones were painted white on their outside with a clear band around the unit to expose the phototube. Their meter socket-type controllers had a clear glass face, the sides of the cover painted gray inside. General Electric controls typically had clear glass covers (some of which are identical to covers used on single-phase "A-base" watthour meters of similar vintage).
On following pages, there are brief descriptions of photoelectric lighting controls manufactured by Fisher Pierce, General Electric and Ripley. These descriptions are intended to describe the physical evolution of controls made by these organizations and will assist the researcher with determining the approximate manufacturing date of them. Electrical and technical data regarding their operation is available at the links page.
Return to main page