IEEE Power & Energy Society


Asheville’s Biltmore Estate

An Elaborate Early Electric Power System

Asheville, North Carolina, has attracted visitors since the early years of the 19th century when doctors would prescribe the area’s cool climate, fresh air, and numerous sulfur springs for the treatment of various illnesses. George Washington Vanderbilt visited in 1888 and decided to stay and build his home, which he named Biltmore. Originally set on 125,000 acres (50,607 hectares) of carefully designed gardens, parks, and woods, the magnificent Biltmore Estate became, and has remained, a world-famous destination. Still in family ownership and managed by the Biltmore Company, the estate and its many attractions are open to the public to see and enjoy. Today, the land that remains part of the estate totals about 8,000 acres (3,239 hectares). Much of the original acreage is now part of the Pisgah National Forest.

While Biltmore is well known, it is less well known that the construction of the mansion in the last decade of the 19th century included the installation of a complex and comprehensive electric supply system to generate and distribute electricity for illumination, heating, and a number of electric power uses, many of which were unknown in most buildings of the day. Happily, much of the original equipment, while no longer in use, still remains in the mansion and is being preserved, interpreted, and appreciated. This article is the story of the elaborate, fascinating, and unique Biltmore electric power system.

This is the 13th “History” article authored by Thomas J. Blalock that has been published in IEEE Power & Energy Magazine since the magazine’s launch in January 2003. Tom earned a B.S.E.E. degree from Lafayette College and an M.E.E.E. degree from Rensselaer Polytechnic Institute. His work as a development engineer at the former General Electric High-Voltage Engineering Laboratory and later as a test engineer in the Transformer Test Department, both in Pittsfield, Massachusetts, included a broad range of duties, including lightning protection and high-voltage switching surge studies. Since retiring from General Electric, Tom has actively pursued his hobby of “industrial archaeology,” with particular emphasis on the exploration, preservation, and careful documentation of historically important and interesting electric power projects and equipment.

We are honored to again welcome Tom back to these pages as our guest history author for this issue of IEEE Power & Energy Magazine.

—Carl Sulzberger

Associate Editor, History

figure 1. Biltmore mansion, now open as a museum, as it appeared in September 2006 (photo by J.C. Pollock, courtesy of Wikimedia Commons).

figure 1. Biltmore mansion, now open as a museum, as it appeared in September 2006 (photo by J.C. Pollock, courtesy of Wikimedia Commons).

Biltmore, located in Asheville in western North Carolina, is considered to be the largest private residence in the United States. The house was built for George Washington Vanderbilt, a grandson of Cornelius (“Commodore”) Vanderbilt of New York Central Railroad fame. This French château-style mansion contains a total of 250 rooms that encompass a floor area of more than four acres (1.62 hectare). Officially opened by Vanderbilt on Christmas Eve 1895, the house is still family owned and is open to the public every day of the year as a museum (see Figure 1).

figure 2. Biltmore mansion as it appeared several years after completion

figure 2. Biltmore mansion as it appeared several years after completion (photo by John H. Tarbell, circa 1900; available from the United States Library of Congress Prints and Photographs Division under the digital ID cph.3c05586).

Biltmore was designed by famed architect Richard Morris Hunt and was constructed between 1889 and 1895 (see Figure 2). Hunt engaged a well-known electrical expert of that era, Dr. Cyprien O’Dillon Mailloux, to engineer an elaborate electrical system for lighting and power throughout the house. This system utilized both alternating current (ac) and direct current (dc) for reasons that are related to what has become known as “the battle of the currents” that was taking place at that time.

Electric Lighting Used Originally

Even though the Edison incandescent electric light had been introduced over a decade earlier, gas lighting was still extensively in use at the time of the planning and construction of Biltmore. However, there is no indication that gas lighting was ever used at Biltmore even though some of the original lighting fixtures in the house appear to have been gas fixtures modified for electric usage.

Early electric generators were most often driven by some form of reciprocating engine, usually steam, but sometimes gas or gasoline engines. These engines required frequent routine maintenance, and, consequently, such electric lighting plants did not usually operate around the clock. This applied for municipal generating stations as well as privately owned plants. Gas, therefore, provided a back-up source of illumination during times that electricity was not available. In fact, combination gas/electric lighting fixtures were still being manufactured well into the 20th century.

For remote locations such as Biltmore, two methods were available to generate gas for lighting on the premises. The first utilized what was known as “producer gas.” This was a variation of coal gas used extensively at the time by municipal gas works. It was a somewhat complicated method since it involved the baking of bituminous coal in a retort and the subsequent addition of small amounts of steam to increase the hydrogen content of the gas. Since Biltmore employed an in-house staff of 30–35 servants, however, it would seem that it would have been relatively simple to provide for the supervision of such an operation.

While it may seem foolhardy today, a much simpler means of providing gas for illuminating a private home involved the use of gasoline vapors. A device known as a Springfield Gas Machine was used extensively for this purpose. It was claimed to be no more hazardous than the use of other forms of gas because the storage of the liquid gasoline was confined to an underground enclosure located some distance from the house.

A centrifugal blower located in the basement of a house sent air to the outside bunker where it picked up the gasoline vapors and then returned to the house for distribution to lighting fixtures. In smaller installations, this blower was operated by means of a hand-wound clockwork mechanism. Sometimes, however, the blower was driven by a small water turbine. The remains of such a system still exist in the basement of the Red Lion Inn located in the western Massachusetts town of Stockbridge.

An early concept for the generation of electric power at Biltmore involved the use of the water supply to operate a hydroelectric plant. As it turned out, the flow from the supply pipe proved to be inadequate for that purpose, but the flow should have been sufficient to operate a water-driven Springfield Gas Machine.

In any event, it was apparently decided during the planning of Biltmore to provide back-up illumination for the house by the use of a large bank of batteries rather than by gas lighting.

n any event, it was apparently decided during the planning of Biltmore to provide back-up illumination for the house by the use of a large bank of batteries rather than by gas lighting.

Design of the Original Electrical System

figure 3. Portrait of Dr. Cyprien O'Dillon Mailloux (photo courtesy of the IEEE History Center).

figure 3. Portrait of Dr. Cyprien O'Dillon Mailloux (photo courtesy of the IEEE History Center).

Dr. Cyprien O’Dillon Mailloux (see Figure 3) was engaged by architect Richard Morris Hunt to design an electrical system for Biltmore to provide lighting and to supply energy for electric motors and other power needs.

C.O. Mailloux was born in Lowell, Massachusetts, in 1860 and became a leading student of Dr. M.I. Pupin, a lecturer on the topic of advanced electrical engineering at Columbia College (now Columbia University) in New York City. By the 1890s, Mailloux had become a recognized and respected expert consulting electrical engineer. He was a charter member of the American Institute of Electrical Engineers (AIEE) and remained active in AIEE affairs throughout his life, including serving as president in 1913–1914. Early in his career, he was editor of Electrical World magazine and remained a frequent contributor to the technical literature until his death in October 1932.

During his early career, Mailloux designed very complex dc power systems for large buildings, many of them in New York City where he maintained his office. These included the original Astoria Hotel (on the site now occupied by the Empire State Building), the Park Row Building in downtown Manhattan, Aeolian Hall, formerly on 42nd Street, and the New York Life Insurance Building.

The systems installed in these buildings utilized both steam engine-driven generators and battery banks to supply dc power continuously to the buildings. Articles describing these power systems in respected magazines such as Electrical World illustrate how elaborate in design they were. The switchboards used with these systems were so complex that it is a wonder that building managers were able to find personnel capable of operating them successfully.

The fragile incandescent lamps of the late 19th century required that the system voltage be very closely controlled. On the other hand, a somewhat higher-than-normal voltage was required to overcome the internal resistance of the batteries so that they could be charged adequately. Then, upon discharge, the battery voltage had to be controlled for the sake of lamp life. In addition, long feeders to the upper floors of the buildings often had to be operated at a higher voltage to account for the voltage drop in them. Finally, it was usually desirable to maintain a separate system for the purpose of distributing power to motors so that their operation would not cause annoying flicker in the incandescent lamps.

Mailloux developed the concept of what was termed a “booster” for use in such systems. This consisted of a low voltage dc generator driven by a dc motor operating from the power system itself. The booster generator could be connected in series with the batteries during the charging cycle so as to provide the necessary increase in charging voltage. Then the same booster could be used inversely in the battery discharge circuitry so as to lower the voltage slightly for the sake of lamp life. Sometimes the booster was connected between the lighting system and the motor (power) system so as to maintain two different voltages simultaneously. Also, it could be used to boost the voltage on long feeders to the upper floors of a building.

At Biltmore, Mailloux specified the use of a dc generator and a bank of batteries, utilizing a booster motor-generator set. In addition, he allowed for the eventual usage of ac for lighting only (suitable ac motors were not yet common during the early 1890s). This flexibility in the choice of current reflected the situation at that time in the field of electrical engineering, which has since come to be referred to as the “battle of the currents.” This involved a conflict between the established use of dc by Thomas Edison and the evolving development of ac power systems by George Westinghouse, Nikola Tesla, and William Stanley. This conflict was of a business nature as much as it was technical.

Mailloux’s Specifications

Fortunately, a copy of C.O. Mailloux’s original specifications for the Biltmore electrical system still exists. It is dated August 1895 and is titled “Main Switchboard for Château of George W. Vanderbilt, Esq., at Biltmore, North Carolina.” It was submitted to “R.M. Hunt, Architect, at No. 1 Madison Avenue, New York City.”

figure 4. Main switchboard in the Biltmore house electrical room (photo courtesy of the Biltmore Estate Archive).

figure 4. Main switchboard in the Biltmore house electrical room (photo courtesy of the Biltmore Estate Archive).

These specifications duly recognize the importance of the main switchboard design, which served as the nerve center of the electrical system. As per common practice at that time, the switchboard was to be made up of four equal marble panels supported by an angle iron frame and having an ornamental border of brass or similar material. The total length of the board was to be about 16 ft (4.88 m) (see Figure 4).

The specifications state that “the switchboard is to serve for the manipulation and control of electric currents derived from various sources, including (a.c.) transformers, (d.c.) dynamo, booster, and storage battery.” Furthermore, it was stated that the transformers were “as likely to be of polyphase as of single-phase kind, and the switchboard equipment must be suitable for either or for both.” This latter statement is certainly an indication of the degree of uncertainty existing at that time concerning the exact type of ac system that would eventually prove to be the most desirable.

The switchboard was to supply motor feeders operating only on dc and supplied from special battery bus bars. It was stated that these would be used for the operation of ventilation and elevator motors. The lighting feeders supplied by the board were to be fed from two sets of bus bars, with both sets capable of operating on either ac or dc.

The two central marble panels of the switchboard contained a total of 16 three-pole knife switches for the lighting feeders and four two-pole knife switches for the motor feeders. These were all equipped with open-link type fuses beneath the switches.

The right-side panel was to contain all of the necessary apparatus for the control of the dc currents from the dynamo, booster, and batteries. The left-side panel was to control the outputs of two banks of step-down transformers, and it also contained three-pole, double-throw switches to select from either bank and to feed either ac or dc to the lighting feeder bus bars.

Interestingly, however, an appendix to these specifications was issued on 31 August 1895, which eliminated the left-side (ac) panel at that time. The remainder of the switchboard was to be installed as soon as possible, however, and was to include all necessary hardware to enable the “appliances on the left panel to be properly connected whenever these are installed, ulteriorly.”

It could be that the original concept of a hydroelectric plant had included the use of a water-powered ac generator. When that possibility proved to be impractical, the ac panel for the switchboard was put on hold.

The actual switchboard installation was by the firm of Hatzel & Buehler, Electrical Contractors, of New York City. John Hatzel and Joseph Buehler had both worked for Thomas Edison and had assisted with the construction of his Pearl Street Station in lower Manhattan in 1882. They formed their electrical contracting company in 1884.

Electrical System Chronology

figure 5. Left-side (ac) switchboard panel in the Biltmore house electrical room (photo courtesy of the Biltmore Estate Archive).

figure 5. Left-side (ac) switchboard panel in the Biltmore house electrical room (photo courtesy of the Biltmore Estate Archive).

The original source of dc power at Biltmore was a gasoline engine-driven generator located in the same subbasement room as the main switchboard. The engine was single cylinder with a rating of 55 brake hp and was manufactured by the White & Middleton Company. It operated at a speed of 150–175 r/min and was belted to a 15-kW Crocker-Wheeler generator via a 10-in (25.4-cm) wide leather belt. Crocker-Wheeler was a major manufacturer of electrical equipment until the middle of the 20th century. The Crocker-Wheeler factory was located in Ampere, New Jersey, a neighborhood of the city of East Orange still locally known as the “Ampere section.” According to Mailloux’s original specifications, there was to be provision for the use of the generator as a motor (operating from the batteries) to start up the engine.

In 1901, a man named Charles Waddell was hired to oversee the operation of the electrical system. He negotiated a contract with the Asheville Electric Company to purchase ac power at night. The electric company also owned the Asheville & Biltmore Street Railway Company and, since the streetcars did not run at night, there was power to spare during those hours.

Charles Waddell (1877–1943) studied electrical engineering at the University of North Carolina but, according to his obituary, he also received training in this field “in the shops of the General Electric Company.”

figure 6. Nash two-cylinder gasoline engine and dc generator (photo courtesy of the Biltmore Estate Archive).

figure 6. Nash two-cylinder gasoline engine and dc generator (photo courtesy of the Biltmore Estate Archive).

Step-down transformers were installed in the battery room, which was adjacent to the room containing the switchboard and dc generator. Nameplate data from some of these transformers indicates that the high voltage ac transmission line to Biltmore probably operated at about 11,000 V (-three phase).

The ac power from the transformers could, of course, be used to operate all of the incandescent lighting in the house at night. Presumably, this is when the final panel of the switchboard was installed. This panel contained the double-throw switches to transfer the lighting feeders from dc to ac (see Figure 5).

All of the lighting feeder switches on the switchboard are three pole. This indicates that a three-wire (110/220-V) distribution system was used throughout the house. When operating on ac, the neutral connection for the feeders would have been obtained from a center tap on the transformer secondary windings. A similar center tap would have been necessary from the battery bank for dc operation.

figure 7. ac-to-dc motor-generator set (photo courtesy of the Biltmore Estate Archive).

figure 7. ac-to-dc motor-generator set (photo courtesy of the Biltmore Estate Archive).

Motors, however, still required dc to operate. To avoid the need to run the gasoline engine at night, mercury vapor (mercury arc) rectifiers were installed to maintain the charge in the batteries. This type of rectifying device was developed by Peter Cooper Hewitt in 1902.

In about 1906, Waddell replaced the original gasoline engine with a Nash two-cylinder engine directly coupled to the dc generator so as to eliminate the need for a leather belt drive. He also installed a motor-generator set near the switchboard. This installation consisted of a three-phase induction motor driving a Crocker-Wheeler dc generator with a rating of 40 kW. Both the Nash generating unit and the motor-generator set remain in place today, but the rectifier units have been removed (see Figures 6 and 7).

Electric Heating

An article written by Charles Waddell appeared in the 5 October 1907 issue of Electrical World and was titled “The Electrical Heating Plant of the Biltmore Estate.”

The heating system for Biltmore was supplied from three large steam boilers that were originally fired by coal or wood. Later on, one of these boilers was converted for oil firing, and all three still exist in the subbasement today.

According to Waddell’s article, additional anthracite-fired boiler installations were used originally to provide steam for use in the laundry and to produce hot water for the house. Also, a small steam engine was used to power refrigeration equipment. The need for steam in the latter case was eliminated by installing a dc motor drive in place of the engine. Waddell says that a dc motor was chosen primarily due to its noiseless operation.

Waddell states that one purpose of his article was to answer skepticism expressed by Electrical World regarding the potential success of the Biltmore electric heating installation when it was first announced a year earlier. Apparently, Waddell was so passionate about this installation that he felt compelled to write a paper on the subject, which was published in 1908 in AIEE Transactions.

This more extensive description included a great deal of cost analysis data that compared electric heating to the use of coal. Waddell presented detailed practical information in this regard. For example, in describing the use of electric irons in the laundry, he states that “to properly iron a handkerchief requires seven minutes, a bath towel four minutes.” In the discussions following the article, the comment is made that “this paper is a little out of the ordinary, but the subject which it treats is well worth the attention of light and power men.”

A horizontal electric hot water heater was installed adjacent to the original coal heater, with the latter remaining available for service if required. The power for the electric heater was three phase at 230 V, and individual switches were used to control the various heating elements. A total heater capacity of 100 kW was installed, but only 30 kW was normally required.

In the laundry, a vertical boiler was installed adjacent to the laundry tubs, which further heated hot water to above the boiling point, thus functioning as a steam generator. The drying room had been heated using steam coils. Electric heaters were substituted and the room was vented into an existing chimney so that the resulting air flow would further aid the clothes drying process.

A 1,000-A service was run to the laundry from the main switchboard via three 500-MCM cables. It was stated that “all laundry apparatus works interchangeably on direct or alternating current.”

Waddell even described the installation of a plate-warming apparatus in the butler’s pantry. The power to operate it was taken from a nearby lighting circuit, and he states that “the lighting system being designed for operation on either the alternating bus-bars or the direct current storage battery bus-bars, it follows that, like the laundry, the plate warmer works interchangeably on the two classes of service.”

He comments on the difficulties encountered with this electrical installation. In particular, service had to be maintained and no dirt or noise was tolerated even though 500-MCM cables had to be run through “stone walls six feet thick, marble floors, and glass tile wainscoting.”

Batteries and Transformers

The batteries originally installed to provide dc power at night are long gone. Archival information indicates that these were Gould lead-acid storage batteries with a capacity of 2,000 Ah (200 A for 10 h, for example).

The right-side switchboard panel, originally for the control of the batteries and the dc generator, has been stripped of some of its original control devices. At the bottom of the panel, there are two circular arrangements of (now empty) holes in the marble. These very well could have been end-cell switches used to control the output voltage of the series-connected battery bank. Two switches would have been required, one at each end of the bank, to control the voltages on both sides of the 110/220-V, three-wire lighting system.

Today, in the former battery room, there are four banks of old step-down transformers of various capacities. These probably were installed at different times in the past as the electrical requirements of Biltmore increased. One of these banks, undoubtedly, was installed to power Charles Waddell’s electric heating installation.

A voltmeter switch on the left-side (ac) switchboard panel provided for the switching of a voltmeter to either of two transformer banks as well as to what is labeled on the switch as a “teazer.” A teaser (modern spelling) is the name given to the auxiliary transformer in a two-transformer T-connection sometimes used to supply three-phase power. There is no evidence of such a transformer bank today, but a large four-pole, double-throw knife switch in the center of this same panel is labeled “power” on one throw and “light” on the other. This indicates that a bank of transformers had been used for both of these functions (see Figure 8).

figure 8. Voltmeter switch showing 'teazer' position (photo courtesy of the Biltmore Estate Archive).

figure 8. Voltmeter switch showing 'teazer' position (photo courtesy of the Biltmore Estate Archive).

One of the remaining transformer banks is very peculiar. It consists of three air-blast transformers (using forced air from a blower rather than oil for cooling) that have nameplate secondary voltages of 375 V. This, of course, has never been a standard voltage for general lighting or power (see Figure 9). However, this type of transformer and this voltage rating were very common in the early 20th century to power rotary converters, which then produced 500-V dc power to operate streetcars.

figure 9. Air-blast transformers and blower (photo courtesy of the Biltmore Estate Archive).

figure 9. Air-blast transformers and blower (photo courtesy of the Biltmore Estate Archive).

These transformers have a primary voltage rating of 21,000 V, but the rating of an old lightning arrester in the corner of the main electrical room indicates that the incoming high voltage ac line operated at a voltage of no more than about 11,000 V. If these transformers were connected to this line in a wye-connection, their secondary voltage would have been close to the 110 V required for lighting purposes.

It so happens that Waddell, prior to his employment at Biltmore, had been the superintendent of the Asheville & Biltmore Street Railway, and, as indicated previously, it was Waddell who promoted the use of ac power from the Asheville Electric Company at Biltmore. It certainly seems possible that he was responsible for the acquisition of these unusual transformers for use at Biltmore.


Around the time of World War I (1914–1918), Biltmore began a conversion to the use of ac power only and, eventually, all of the dc apparatus was retired. The batteries no longer exist, but the switchboard room appears much as it did during the period when dc power was still being used.

Extensive rewiring of the house began in the 1980s, and the old switchboard was completely retired from service after 1990. Today, special behind the scenes tours are conducted of the subbasement areas, and guests are able to safely view the impressive marble switchboard.

It is certainly very fortunate that so much of this fascinatingly complex early electric lighting and power system has been retained and preserved until today.


The author is deeply indebted to Jill Hawkins, associate archivist at the Biltmore Company, for providing valuable information, photographs, and relevant material from the Biltmore Estate Archive for this article.

For Further Reading

C. Waddell, “The electrical heating plant of the Biltmore Estate,” Electr. World, vol. 50, no. 14, pp. 650–652, Oct. 5, 1907.

C. Waddell, “Notes on the electric heating plant of the Biltmore Estate,” AIEE Trans., vol. 27, pt. 1, pp. 651–66, 1908.

P. H. Thomas, “Discussion on notes on the electric heating plant of the Biltmore Estate,” AIEE Trans., vol. 27, no. 1, pp. 667–668, 1908.

Biltmore House and Gardens (booklet). Asheville, NC: The Biltmore Company, 1976.

S. C. McKendree. (2000). A technological tour of the Biltmore Estate. Available Online.

(2011). Biltmore. [Online]. Available Online.

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