Milestone-Proposal:Worlds First Reliable High Voltage Power Fuse

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Docket #:2009-09

This is a draft proposal, that has not yet been submitted. To submit this proposal, click on the edit button in toolbar above, indicated by an icon displaying a pencil on paper. At the bottom of the form, check the box that says "Submit this proposal to the IEEE History Committee for review. Only check this when the proposal is finished" and save the page.

To the proposer’s knowledge, is this achievement subject to litigation?

Is the achievement you are proposing more than 25 years old?

Is the achievement you are proposing within IEEE’s designated fields as defined by IEEE Bylaw I-104.11, namely: Engineering, Computer Sciences and Information Technology, Physical Sciences, Biological and Medical Sciences, Mathematics, Technical Communications, Education, Management, and Law and Policy.

Did the achievement provide a meaningful benefit for humanity?

Was it of at least regional importance?

Has an IEEE Organizational Unit agreed to pay for the milestone plaque(s)?

Has the IEEE Section(s) in which the plaque(s) will be located agreed to arrange the dedication ceremony?

Has the IEEE Section in which the milestone is located agreed to take responsibility for the plaque after it is dedicated?

Has the owner of the site agreed to have it designated as an IEEE Milestone? Yes

Year or range of years in which the achievement occurred:


Title of the proposed milestone:

World's First Reliable High Voltage Power Fuse

Plaque citation summarizing the achievement and its significance:

200-250 word abstract describing the significance of the technical achievement being proposed, the person(s) involved, historical context, humanitarian and social impact, as well as any possible controversies the advocate might need to review.

IEEE technical societies and technical councils within whose fields of interest the Milestone proposal resides.

In what IEEE section(s) does it reside?


IEEE Organizational Unit(s) which have agreed to sponsor the Milestone:

IEEE Organizational Unit(s) paying for milestone plaque(s):

Unit: Chicago
Senior Officer Name: William Nartker

IEEE Organizational Unit(s) arranging the dedication ceremony:

Unit: Chicago
Senior Officer Name: John A Zulaski

Unit: Chicago
Senior Officer Name: Kristin McInnis

IEEE section(s) monitoring the plaque(s):

IEEE Section: Chicago
IEEE Section Chair name: William Nartker

Milestone proposer(s):

Proposer name: John A Zulaski
Proposer email: Proposer's email masked to public

Please note: your email address and contact information will be masked on the website for privacy reasons. Only IEEE History Center Staff will be able to view the email address.

Street address(es) and GPS coordinates in decimal form of the intended milestone plaque site(s):

6601 North Ridge Boulevard, Chicago Illinois, 60626

Describe briefly the intended site(s) of the milestone plaque(s). The intended site(s) must have a direct connection with the achievement (e.g. where developed, invented, tested, demonstrated, installed, or operated, etc.). A museum where a device or example of the technology is displayed, or the university where the inventor studied, are not, in themselves, sufficient connection for a milestone plaque.

Please give the address(es) of the plaque site(s) (GPS coordinates if you have them). Also please give the details of the mounting, i.e. on the outside of the building, in the ground floor entrance hall, on a plinth on the grounds, etc. If visitors to the plaque site will need to go through security, or make an appointment, please give the contact information visitors will need. The plaque will be installed on the property of S&C Electric Company in Chicago, Illinois. This is the headquarters and primary manufacturing facility of S&C (formerly Schweitzer & Conrad—the company that introduced the Liquid Power Fuse). The device was manufactured at this facility through the 1990s.

Are the original buildings extant?


Details of the plaque mounting:

How is the site protected/secured, and in what ways is it accessible to the public?

The entrance to S&C’s facility is accessible via sidewalks to the surrounding neighborhood, which is a largely residential area. S&C Electric Company’s security staff is on-site 24 hours a day, and keeps watch over the entrance area where the plaque will be installed.

Who is the present owner of the site(s)?

S&C Electric Company

What is the historical significance of the work (its technological, scientific, or social importance)? If personal names are included in citation, include justification here. (see section 6 of Milestone Guidelines)

This invention provided an economical, reliable means for interrupting high-current short-circuits in electric utility substations. It allowed utilities to expand their delivery of dependable electrical service to businesses and consumers.

What obstacles (technical, political, geographic) needed to be overcome?

Existing circuit interruption technologies were wholly inadequate. They could produce damaging overvoltages and were a fire hazard. An entirely new technology needed to be developed. Consider the 1905-vintage book, High-tension power transmission, prepared by the American Institute of Electrical Engineers. In discussing circuit interrupting techniques in Volume 2, it points out that, “For high-tension switching, use has been made of a long arc broken between carbon terminals, long-inclosed fuse, a fuse drawn through a tube filled with a fine, non-conducting powder, and of oil switches.” The text notes that, “The first two types, while interrupting the circuit well, draw an arc of excessive length and produce a surging which may result in an increased potential of at least as much as 50 per cent.” The text further states that, “The type of switch where a wire is drawn through a tube filled with powder is found to operate successfully up to 40,000 volts and without serious surging on the circuit, but the powder being blown out with great force, scatters over the entire station, and is in consequence not allowable.” With regard to flammable-oil-filled switches, the text indicates, “The vertical-break switch has the advantage that the amount of oil contained in the oil-tank is relatively small, and will add to possible conflagration only a slight amount of fuel. This switch is found on severe short-circuits often to blow all the oil out of the tank unless the tank is built very strongly . . .”

What features set this work apart from similar achievements?

This fuse design was much more reliable than previous power fuses. At the time, breakdowns in electrical substations were common, negatively impacting service reliability for customers of electric utilities. Often, the problems were found to be attributable to poorly performing fault protection equipment. The inspiration for the device came to the inventors—two Commonwealth Edison engineers, Nicholas J. Conrad and Edmund O. Schweitzer—after they investigated a fire at the Fisk Street Generating Station. They concluded that the cause of the fire was a power fuse failure. Schweitzer and Conrad’s fuse design differed from predecessors through its use of a special arc-extinguishing liquid that assured proper interruption of short circuits, and a fusible element that offered unmatched precision in operating only when called upon. The fuse was constructed to withstand the very high temperatures associated with interrupting high-current faults, and was sufficiently rugged so it could be applied outdoors. The Schweitzer and Conrad Liquid Power Fuse played a major role in the adoption of outdoor distribution substations—a central component of electrical transmission and distribution systems today.

Supporting texts and citations to establish the dates, location, and importance of the achievement: Minimum of five (5), but as many as needed to support the milestone, such as patents, contemporary newspaper articles, journal articles, or chapters in scholarly books. 'Scholarly' is defined as peer-reviewed, with references, and published. You must supply the texts or excerpts themselves, not just the references. At least one of the references must be from a scholarly book or journal article. All supporting materials must be in English, or accompanied by an English translation.

Supporting materials (supported formats: GIF, JPEG, PNG, PDF, DOC): All supporting materials must be in English, or if not in English, accompanied by an English translation. You must supply the texts or excerpts themselves, not just the references. For documents that are copyright-encumbered, or which you do not have rights to post, email the documents themselves to Please see the Milestone Program Guidelines for more information.

Please email a jpeg or PDF a letter in English, or with English translation, from the site owner(s) giving permission to place IEEE milestone plaque on the property, and a letter (or forwarded email) from the appropriate Section Chair supporting the Milestone application to with the subject line "Attention: Milestone Administrator." Note that there are multiple texts of the letter depending on whether an IEEE organizational unit other than the section will be paying for the plaque(s).

Please recommend reviewers by emailing their names and email addresses to Please include the docket number and brief title of your proposal in the subject line of all emails.