Here is a photo of a 13,800/4800v.three phase step down transformer bank. 13,800 volts comes from the left. The three 150 kva step down transformers are mounted on a cluster mount bracket, and protected by 3 cutouts hung from the crossarm on the 13,800 volt side of the pole. The 4800 volt primaries are on the right side of the pole. Below the transformer bank is a 1/0 ATC (triplex) secondary cable.
Here is a photo of more conventional WMECO construction. This pole, pole 157/50 on West St. in Amherst, shows the long pole top insulator pin in use from 1966 through early 1968, the last years before armless construction became the standard. This line was converted to 13kv from 4800 volts in 1966. The pole is a 1966 40' Class 4 SPC. The transformer is a 25kva CSP type. The primary wire is 4/0 TWACSR. The secondary is 1/0 ATC (Aluminum Triplex Cable).
This is a photo of the armless construction used by WMECO and CL&P (Conneticut Light and Power) from 1968 to 1977. In the late 1960's many utilities all over the country began to use steel brackets instead of wood crossarms to support line conductors. There was a great drive at the time to improve the appearance of utility installations and these steel brackets gave the line a more compact, streamlined appearance. Unfortunately, they made for unsafe working conditions for linemen, since the line conductors were so much closer together. Most utilities have abandoned armless construction and returned to the wood crossarm because of its greater safety. WMECO began using crossarms again in 1979.
Here is a photo of pole 372/33M on West Pomeroy Lane in Amherst. This is an example of an armless riser pole. A riser pole is a pole on which a line goes underground. This is a 3-Phase riser. The cutouts are mounted on armless brackets. Lightning arrestors are mounted near the cutouts. The cable terminations are mounted below the cutouts on pintype insulators. This pole carries 556.5 MCM wire, the largest size in common use by WMECO. There is no secondary circuit, so a 1/0 ACSR wire serves as the neutral conductor. This line was rebuilt in 1975 due to a road widening project. The pole is a 1975 40' Class 4 SPA.
This is pole 129/4, on South Prospect St. in Amherst. This is an example of current WMECO riser pole construction. The cable terminations and lightning arrestors are mounted on a second, lower crossarm. This riser was replaced in 1998. This pole had armless construction from 1971, when the line was converted to 13,800 volts until 1998. The pole is a 40' Class 3 SPC set in 1956. When originally installed, the pole carried 3 4800/120/240v. transformers feeding an underground service. When the line was rebuilt in 1971, it was decided to switch to padmounted transformers on the ground, and feed them with high voltage underground cable from the pole.
This is a photo of pole 44/10 on Flat Hills Rd. in Amherst. This pole is an example of a typical 4800v. CSP transformer installation. The CSP transformer (CSP stands for Completely Self Protected) needs no lightning arrestors or cutouts because they are built into the transformer itself. Overload protection is provided by an internal circuit breaker. The lightning arrestors are mounted on the outside of the transformer case. They are the tubelike objects on either side of the case. This is one pole up from the next picture. The pole is a 35' class 5 CCA treated pole of unknown date. The primary conductor is #4 ACSR, installed in 1946.
This is an image of pole 44/11 on Flat Hills Rd. in Amherst. This is a 4800v. conventional transformer installation. The cutouts, which are fused disconnects, are the rectangular objects seen hanging from the crossarm. The lightning arrestors are on the opposite side of the crossarm. The cutout on the left is a recent replacement. This line was built in 1946. The primary conductor is #4 ACSR. The pole is a 1946 35' Class 5 SPC.
This WMECO pole shows a single phase 250 kva step down transformer. 7900 volts wye comes in from the left of the photo, and is stepped down to 4800 volts delta to feed the circuit to the right. The pole is a 1974 40' Class 4 SPA. The 7900 volt primary is 1/0 TWACSR, the 4800, #2 ACSR.
Here is a photo of what WMECO riser pole construction was like before armless construction became the standard. This is pole 4B/30 on Amity St. in Amherst. Two double arms are installed. The line is deadended on the top arm. The cutouts are mounted on the arm below. The cable terminations are mounted on the single arm on the bottom. Although the line on Amity St. was rebuilt in 1971, this pole was set in 1968 to provide underground service to buildings on South Pleasant St. From 1968 to 1971, three 4800/13,800v step-up transformers were mounted on this pole to provide 13kv to the underground system. They were removed when the line was changed over to 13kv in 1971.
This is a picture of pole 4B/29 on Amity Street in Amherst. This is another example of WMECO and CL&P armless construction. This is a vertical tap. Three armless brackets are used to support the line conductors. The line to North Prospect Street is taken off of this line by means of the suspension insulators attached to the armless brackets. This line was rebuilt in 1971. The only change made to this pole since then is the replacement of the original porcelain insulators with the newer plastic "vice-grip" insulators.
Here are some photos of what might be the oldest poles in service in the United States. These poles are in Virginia, and were set in 1897 by AT&T as part of their Washington-Norfolk toll line. They were one of the very earliest installations of creosoted southern pine poles. The poles were sawn square with a taper of 1 inch per 5 feet. This was an experiment at the time. Most utilites, electric and telephone, were setting untreated poles. Almost 10,000 of these poles were set in 1897. A few of them were still in use in 1996, when I took these pictures. The poles were abandoned by AT&T and were then being used by the Continental Telephone Company for local service. Two of the pictures show the poles with two CATV lines installed above the telephone lines. I don't know how many of these are left, but probably not too many. These pictures were taken in Bowling Green Virginia, on route 631. The poles are quite short, no longer than 30 feet.
Here is another pole, part of a very old and unusual line. This pole is octagonal, tapering gradually from butt to top, and was set in 1898, also by AT&T and were once part of the main toll line entering New York City from the south. This pole is on Arthur Kill Rd, on Staten Island. The pole was since abandoned by AT&T, and now carries a Con Edison service drop cable and a single fire alarm wire. There were only about six of these 1898 poles still in service when these pictures were taken in 1996.
Here is another photo of one of these 1898 poles. This one shows a pole carrying three high voltage switches mounted under the crossarms. The tubular things mounted on the crossarms are lightning arrestors. Below is an open wire secondary circuit. The portion to the right of the pole, with four wires is three phase. The portion to the left with three wires is single phase. Below the secondary is a high voltage cable. This pole is carrying quite a heavy load, especially considering it was 98 years old when this picture was taken!
Here is another photo of the same pole, seen from across the street.
Here is a picture of the groundline area of the pole seen in the previous two pictures. This pole has been reinforced by a piece of steel driven into the ground and strapped to the pole.
Here is another picture of an 1898 Creosoted Southern Pine pole on Staten Island. This pole is much like the one on Arthur Kill Rd. All of these poles are about 40' long. This one is at a street intersection, and carries the lines of the Consolidated Edison Company. There is another Con Ed pole line on the opposite side of the street. The large cable on this pole is not a telephone cable. It is a Con Ed high voltage cable. Con Ed runs some of its high voltage circuits in cable to save space on its crowded poles.
Here is a photo of one of the 1898 octagonal poles with a fire alarm box on it. The upper portions of this pole were shown earlier. It is the one at the intersection.
Here is a picture of one of the only Chestnut poles that I have seen anywhere. This pole is in Natick, Massachusetts, and carries the lines of the Boston Edison Company. Its age is unknown to me. It is a 55' pole, unusually tall for a chestnut. The top crossarm carries a 4160v. circuit, insulated for 13kv with large porcelain multipart insulators. The lower crossarm carries another 4160v. circuit. A "3 in 1" three phase transformer of recent vintage is below the lower crossarm. A triplex secondary cable runs below the transformer. Next to it is the 55' SPP pole that has probably replaced this pole by now. Notice that this pole is not straight. This is typical of chestnut poles. Chestnut trees didn't grow straight, unlike the Cedar and Southern Pine that are the principal pole species now.
Here is a vertical shot taken at the base of the 55' Chestnut pole. This photo emphasizes the fact stated before that chestnut poles aren't straight. Notice that the two crossarms don't line up with each other.
Here is a picture of a Williams Polemount. This is a way of bolting poles to concrete foundations so that no wood is exposed to the soil. The pole is held by the cast iron bracket you see, which grips the pole with six curved bolts which wrap around the pole. Four very large bolts connect the brackets to the foundation. These Williams Polemounts were marketed during the 1920's. The only place I have seen them, other than old ads in Electrical World, is on Boston Edison's lines in Natick. The 55' Chestnut pole seen in the preceeding three pictures is held up by one of these polemounts, which is perhaps the reason why it was still standing when I took the pictures in 1998.
This image was taken in Cranberry, PA and shows some very tall (100 feet or more) steel poles carrying a line in the 115kv range on top, supported by horizontal vee string insulators. Below runs a distribution line most likely in the 13 kv range.
Here is a photo of a switch on the same line in Cranberry PA. This is a three way switch that allows power to be routed in two different directions, either down the main line along the highway, or to the line branching off to the left. It's really quite a structure.
Here is a line of Richmond Power & Light (RPL) in Richmond, Indiana. This is a double circuit 13.8kv line, with the circuits mounted vertically on post insulators on the pole on the right, and on brackets on the poles to the left. On top is a grounded shield wire that protects against lightning strikes.
This photo of an RPL line shows a 55' pole carrying 13.8kv on horizontal post insulators with shield wire above, and on a four pin, 5'7" crossarm is 4160v (4.16kv). The 13.8kv line conductors are 4/0 bare copper. The 4160 line consists of 4/0 weatherproof copper phase wires and a 2/0 weatherproof copper neutral. The neutral wire is carried on the glass insulator, while the phase wires have brown porcelain insulators. The pole is dated 1970, and has the blond color charactaristic of poles treated with pentachlorophenol (penta), but I am unsure of the species.
Here is a picture of a pole in a 69kv RPL line. This line was brand new in 1996 when the picture was taken. The line is mounted on horizontal post insulators. The metal objects mounted to the left of the insulators are vibration dampers. The conductor is 336.4 MCM AAAC (all aluminum alloy conductor).
Here is a 69kv riser pole. The 69kv line is carried underground from a substation across the street. The underground line connects with the overhead at this pole. The line is deadended on polymer (plastic) suspension insulators.
This is a photo of a 69kv switch mounted on a steel pole. This line is across the street from that shown in the earlier pictures. The switch allows the line to be switched between two 69kv underground feeders coming out of a substation.
This is another RPL line in Richmond, Indiana. This is a 69kv double circuit line mounted on 90' 1994 Douglas Fir poles. The poles are class H2, (H1 is the class heavier than class 1, H2 is heavier still, etc.) This line is carried on vertical post polymer (plastic) insulators. On the crossarm below the 69kv line is a 13.8kv line.
Here is a photo of a RPL line with 69kv on horizontal post insulators on the top. Below is a 13.8kv line on 8' crossarms. Below that is a 4160v line. The poles are penta treated 1964 Western Red Cedar ranging in height from 65 to 80 feet. This line has two underbuilds. An underbuild is a line of a lower voltage that is carried beneath the line on the top of the poles. Both the 13.8kv and 4160 circuits can be described as underbuilds, as can the secondary circuit below the 4160, although I'm not counting that.
Here is another photo of the same line. The 69kv conductors on top are 336.4 MCM ACSR. The 13.8kv conductors below the 69kv are 4/0 bare copper. The 4160v conductors under the 13.8kv are 4/0 weatherproof copper. The secondary cable below the 4160v is a 4/0 parallel lay aluminum cable. This is a ribbon type cable, as opposed to the spiral design used by most New England utilities.
This is another photo of the same line. The 13.8kv circuit has an air break sectionalizing switch here. Below it, on the 4160v line is a single phase transformer feeding a secondary circuit.
Here is a RPL pole carring 4160 on the top crossarm. Mounted on the crossarm below is a single phase transformer feeding an open wire secondary circuit mounted on racks. RPL mounted transformers this way starting at the turn of the century and continued the practice until 1967. Mounting transformers on crossarms below the primary crossarm made the cutouts (fuses) easier for the lineman to access, as well as making it easier to replace the transformer. The heavy transformer didn't have to be hoisted all the way to the top of the pole.
Here is another pole in the RPL system, this one a 35' SPP with a 4160v single phase (actually 2400v when it's single phase) line on it. This pole is in a park and feeds some athletic field lights. The two devices mounted on the crossarm are for primary metering. RPL meters this line at the primary (high voltage). At the base of the pole is a box with the meters inside.
Here is a photo of RPL 4160v three phase primary metering. This structure consists of two 35' class 5 1954 SPP poles. The devices mounted on the crossarms are voltage and current transformers that step down the voltage and current in the line to values that can be read by the meter mounted in a box at the base of the pole.
Here is another view of the same structure.
Here is a RPL 4160v three phase transformer bank mounted on a platform supported by two poles. This type of installation was used for very large three phase transformers. Smaller ones would be carried by a single pole.
Here is another RPL pole, carrying a vintage Westinghouse CSP (completely self protected) transformer. This transformer, with its unique octagonal case, probably dates from the 1930s. Instead of having an internal circuit breaker, like modern CSPs, this one has two fuses mounted on the outside of the case. One can be seen as the white object appearing on the left side of the transformer case. The octagonal case was a feature of Westinghouse distribution transformers of the period, both CSP and conventional.
Here is a photo of a 2400v line of the Massachusetts Electric company in Spencer, Mass. On the crossarm at the top of the pole is a 2400v 3 phase circuit. If you look closely, on the other side of that same crossarm are two unused insulators. They are for a series street lighting circuit that was removed. At one time, most street lights were in series circuits which allowed them to be switched on and off from one point. A large number of lamps were in the circuit. The voltage applied across these circuits was from 2400 to 10,000 volts, with a voltage drop of about 120v at each lamp. Nowadays, street lights are controlled by individual photocells and there is no need for large separately switched circuits dedicated to street lighting only.
Here is another photo of a pole further down the same line. The open space on one side of the crossarm was dedicated to the same series street lighting circuit discussed in the last photo. This pole has a double dead end and three fused disconnect switches.
Here is a photo of a 4800v line of the Western Mass Electric Co. on Union Street in Easthampton Mass. This pole was replaced when this line was rebuilt in 2002. This type of transformer mounting common on old RPL lines in Indiana, below the secondaries, was standard WMECO practice from 1931 until about the 1950's for larger transformers. The transformer is single phase, and it fed a heavy 3 phase secondary circuit which was fed from a number of different points by both single and three phase transformers.
Here is a photo of a pole of the Wellesley Electric Light Department on Route 9 in Wellesley Mass. The pole is a 40' Class 4 1956 SPC. The pole carries a 3 phase 4160v primary circuit on the top crossarm, 3 fused cutouts on the middle arm and a 120/240v single phase secondary circuit on the longer 8 pin crossarm on the bottom. The transformer is a 4160/120/240v. "three in one" three phase transformer. This is actually three single phase transformers in a single case. A three phase secondary circuit fed by this transformer is mounted on a 3 spool rack below the lowest crossarm.
Here is another photo of the same pole. The pole is still standing, but the 4160v primary circuit and both open wire secondary circuits were removed along with the three crossarms and the transformer when the line was converted to 13kv a few years ago.
Here is a photo of a pole of the Westfield Gas & Electric Light Dept. in Westfield Mass. This is a riser pole. Two 4160v three phase circuits surface from underground conduits on this cedar pole. The circuits are protected by oil immersed fuses, which are the grey bottle shaped objects mounted on one of the lower crossarms.
Here is another photo of the same pole.
Here is a photo of an old cedar pole further down the same 4160v double circuit line in Westfield. On the top crossarm is one 4160v three phase circuit. The bottom crossarm carries the other.
This photo is of a very early sodium vapor streetlight. This design came out about 1939. The photo was taken in Granby, Connecticut and the lamp is mounted on a 35' 1953 Creosoted Southern Pine (SPC) pole. The bulb is a long tube and it gives a distinctly yellow light. The original lighting on the Coolidge Bridge into Northampton MA, built in 1939, was very similar to this.
Here is another photo of the same installation.
Here is a photo of one of Boston Edison's lines. This particular pole, part of a 3 phase 4160 volt line has an oil switch, the squarish device hanging under the crossarm. This is a 3 phase oil switch, and all three phases are switched together. The switch contacts are immersed in transformer oil to protect them from moisture and arcing. Oil switches have been used by Boston Edison for probably 75 years or more and they are a very safe method of switching lines, since the switch contacts are completely enclosed.
Here is the first of the Pictures taken in Los Angeles. There is probably no better place in the United States to look at pole lines than LA. It's a large city and the majority of the lines are above ground. Due to the population density, there are often multiple primary circuits, along with sub transmission lines on one pole line. This makes for some very tall poles. In addition, pole line construction methods changed much more slowly in the LA area, so you can see some types of construction that have long ago vanished from the streets of other parts of the country. Quite a few series street lighting circuits are still in operation in the LA area, the last survivors of a technology that at one time was utilized by just about every electric utility in the United States.
This first picture is of a double circuit 66kv line. This type of 66kv double circuit line is found all over the Los Angeles area. There is no overhead ground wire because lightning strikes are rare in Southern California. This basic design dates back at least to the 1920's. The line conductors are attached to the crossarms with suspension insulators.
Here is another variant of the 66kv Double Circuit Line. Two conductors are attached to the top crossarm, and four to an extra long bottom crossarm. This is done to provide extra clearance from tress and other obstructions. The poles are 70' 1962 Creosoted Douglas Fir. Douglas Fir seems to be the most common pole species in Southern California.
Here is a 66kv single circuit line. This is carried on a 70' 1963 creosoted western red cedar pole. Far below the two crossarms carrying the 66kv conductors is a crossarm carrying a circuit of about 12.5kv*.
This is another 66kv double circuit line illustrating the type of construction that began to be used about 1963. Horizontal post insulators attached to fiberglass rods replaced the suspension insulators and wood crossarms of the earlier lines. This type of construction has been abandoned and the newest 66kv lines have reverted to the traditional type of construction used before 1963. Evidently, there was a problem with this design. The pole here is an 80' 1966 Douglas Fir treated with the Cellon process (DFG). Below the 66kv lines is a 12.5kv* line. A 12.5kv* 3phase underground circuit riser is also attached to this pole.
Here is a view of another pole in the same line as the previous picture showing the same 66kv construction. The pole is also an 80' 1966 DFG. The 12.5kv* circuit has an air break sectionalizing switch. Below that is a 3 phase transformer bank and an underground service.
Here is a picture of a line of the Los Angeles Department of Water & Power that shows one of the heaviest concentration of circuits I have ever seen. The pole is a 95' (yes, a 95 footer) 1988 Douglas Fir treated with Pentachlorophenol, as are all the adjacent poles in this line. The top three crossarms carry two 66kv circuits. The arm below that carries 34.5kv. On the arm below that, about 13kv. The two arms below that carry 1 4800 volt 3 phase circuit each. One of the 4800 volt circuits deadends on this pole and is carried underground. You can see the 3 cables entering the conduit running down the side of the pole. Just getting this entire pole in one frame was a challenge!
The pole on the left in this picture has a rather unusual bracket mounted on it. This bracket composed of six post insulators, was designed by famed industrial designer Henry Dreyfuss for Southern California Edison (SCE). It is called the "radiate" design, because the insulators appear to radiate from a central point. The pole is an 80' 1975 Creosoted Douglas Fir (DFC) and carries a 66kv double circuit line, and a 12.5kv* line below. These brackets were developed in the mid 1960's for 66kv circuits and seem to have been discontinued in the late 1970's. The pole on the left, a 75' 1978 DFP uses horizontal post insulators attached to the ends of wood crossarms to carry the 66kv line. Presumably, the use of the Dreyfuss brackets was discontinued by SCE between 1975 and 1978.
Here is a picture of a 66kv line crossing over a perpendicular line of lesser voltage. In order to obtain the necessary clearance, SCE used a 100' pole here. Fortunately, the two major electric utilities in the LA area, Southern California Edison (SCE) and the Los Angeles Dept. of Water and Power (LADWP) both use dating nails and length nails on their poles, so getting the age and height of a pole is easy. There was no "100" nail available, so this pole was marked with two "50" nails. Thus the nails read 50 50 59, meaning a 100' 1959 pole (DFC in this case). This pole carries one of the Dreyfuss brackets, which did not yet exist in 1959, so this bracket must be a later installation. Below the 66kv is a 12.5kv* line, and on the crossarm below that, a 4160 volt 3 phase line. (SCE uses 4160 volts for much of it's distribution, LADWP 4800 volts.)
This photo is of a double circuit 34.5kv line. One 34.5kv circuit is undergrounded on the pole towards the right, the other on the next pole to the left. Again, the same sort of vertical construction seen on the double circuit 66kv lines is seen, but instead of suspension insulators, large multipart porcelain insulators are used. The poles here are 55 footers and the clearances between crossarms are less than they are with the 66kv lines.
Here is another picture of the same double circuit 34.5kv line. The pole is a 55' 1956 DFC. Notice that the insulators on one side of the three 34.5kv crossarms appear white. This most likely means that they are newer. About 1965, many insulator manufacturers switched from a brown glaze to a gray glaze that was supposed to blend in with the sky better. Below the 34.5kv are 2 4800 volt 3 phase circuits. Tapped off one of the circuits is an open delta transformer bank. Below runs a bare copper open wire secondary circuit.
Here is another pole in the same line. This 55' 1956 DFC carries a capacitor bank tapped off one of the 4800 volt circuits. Multiple 4800 volt circuits are common on LADWP lines, of which this is one. The circuit with the heavier conductors, about 4/0 weatherproof copper, is a 4800v distribution feeder. At various points along the feeder, 3 phase 4800 volt circuits called mains are tapped off. The 4800 volt mains run parallel to the feeder here, on opposite sides of the crossarm. The mains uses smaller conductors than the feeders. Transformers and single phase taps are only taken off the mains. Both the capacitor bank here and the transformer bank in the last picture are tapped of the mains.
Here is another pole in the same line showing the type of cutouts used by LADWP on 4800 volt circuits. These three fused cutouts have porcelain enclosures with a light brown glaze. They protect the 4800 volt mains, as the point where the mains branch off from the feeder is only one or two poles away. I have never seen this type of cutout used outside of Southern California. The pole here is a 50' 1956 DFC.
Here is a SCE 66kv single circuit line with a 12.5kv* circuit on the opposite side of the pole. The 12.5kv* circuit uses the 66kv crossarms. This particular type of dual voltage construction is common in Southern California. Since the 12.5kv* line runs alongside, rather than under the 66kv, it is technically not an underbuild. The 12.5kv* line has a single phase transformer feeding a street lighting circuit. The 12.5kv* system used by SCE is mostly three wire, as it is here, so the 12.5kv* transformer needs two cutouts. The pole is a 70' DFP.
Here is another photo of the same SCE line with 66 and 12.5kv* circuits sharing crossarm space. Here the 12.5kv* line branches off. The suspension insulators for the 12.5kv* tap are attached to the ends of the crossarms, making a buckarm unnecessary. The pole is a 70' DFC.
Here is a 65' 1952 DFC carrying 2 12.5kv* circuits in a vertical configuration on the top crossarm. Below are 2 4160v three phase feeders. Below that is a 4160v three phase main with a single phase transformer tapped off of it to feed a street lighting circuit. Dead ended on the lowest crossarm are two series street lighting wires that are no longer used. The neutral for all three 4160v circuits is carried on the bottom crossarm. This is an SCE pole.
*(It is actually not 12.5kV, but 12kV delta. California has long required that all distribution circuits higher than 4kV must be delta. Corrected by ddahle.)