In the United States District Court, the plaintiffs, Pearl Farmer (suing in her capacity as administratrix) and Mildred Gibson Hammontree (suing as widow), were awarded jury verdicts for the deaths by wrongful act of their respective decedents. Jury awards were in amounts of $33,000 for the death of Joseph Howard Hammontree and $29,-000 for the death of Owen Franklin Hammontree. The cases were consolidated for trial and by stipulation have been heard together on this appeal. The defendants made timely motions for directed verdicts, both at the conclusion of the plaintiffs’ proof and at the conclusion of all the evidence in the case. These motions and later motions for judgments non obstante veredicto were overruled by the district judge. The single issue for decision on this appeal is whether there is substantial evidence to support the verdicts of the jury. Throughout these proceedings, appellants for all practical purposes properly may be and have been treated as the same person.
The appellants (defendants) are engaged in the distribution of electrical power purchased from the Tennessee Valley Authority in the Maryville, Tennessee, area. They own, operate and maintain a system of transmission lines from which customers are served. The Tennessee Farmers Co-operative Fertilizer Plant, where the plaintiffs’ decedents were employed and where they lost their lives by electrocution, was one of the customers of the utility. The Liberty Mutual Insurance Company, carrier of the workmen’s compensation on the employees of the fertilizer plant, has made settlement for the two deaths. These actions were brought for the benefit of that insurance company and of all others who, under Tennessee law, are entitled to participate in the recoveries.
Upon the trial, development of the facts was necessarily a difficult task, most of the witnesses being experts whose technical testimony and opinions-were couched in the language of electrical engineers. The briefs and oral argument here and the entire record of the proceedings in the district court have been carefully considered, with the result that we find no inconsistency in the material testimony of the witnesses after assumptions have been separated from factual evidence.
There is no dispute as to the extent of the physical equipment owned and maintained by the appellants. Their transmission lines are connected into the T. V. A. system at a sub-station where 13,200 nominal volts are received. At various points along this line, energy is tapped off for distribution. In close proximity to the fertilizer plant where the accident occurred, appellants own transformers which step down the 13,-200 nominal volts to a more usable potential of 440 volts. From the secondary connections of these transformers the plant’s “delta-delta ungrounded three-phase” electrical system is supplied. Another transformer steps down the 440 volts to a single-phase energy at 110 volts for lighting purposes. Appellants’ wires are connected to those of the plant outside the building at the “weather head.” Beyond the weather head, the wiring is owned and maintained by the consumer and the utility has no jurisdiction.
The appellants’ hypothesis is that the electrocution was caused ultimately by faulty insulation on certain Kerney connectors located within the fertilizer plant’s wiring system over which appellants had no authority. It is contended further that the failure of the consumer to supply an independent ground wire for the portable rubber-tired electric conveyor, which became charged *458with electricity while the decedents were in the act of turning it around, was a primary contributing factor to their deaths; and that such a ground wire in all likelihood would have prevented the accident by causing a fuse to blow, or by providing a path of low resistance to ground. In summary, the hypothesis of the appellants is that the defective wiring which proximately caused the deaths of these men was that of the fertilizer plant and not that of appellants, whose wires terminated at the weather head of the plant building.
Appellees, in the capacity of cross-appellants, insist that the trial court was in error in ruling that the doctrine res ipsa loquitur has no application under these circumstances. The effect of that doctrine, if applied, would necessarily shift the burden of producing evidence to the appellants. It is well settled that the doctrine res ipsa loquitur has no application where the defendant is not in exclusive control of the instrumentality which caused the plaintiff’s injuries. Coca-Cola v. Sullivan, 1942, 178 Tenn. 405, 158 S.W.2d 721, 171 A.L.R. 200; Susman v. Mid-South Fair, 1944, 180 Tenn. 471, 176 S.W.2d 804. Here, the appellant had no control of the wiring within the fertilizer plant." “It is the general rule that where a company merely transmits its electric current from its lines to the consumer wires, which it did not install and does not control, that the company has no duty to inspect such wires and is not liable for injury caused by defects in them.” Dabbs v. Tennessee Valley Authority, 1952, 194 Tenn. 185, 250 S.W.2d 67, 69. Appellants’ hypothesis, which is supported by evidence, is that the accident resulted from defects in the wiring of the consumer. Under these circumstances, the ruling of the district court as to the res ipsa loquitur doctrine was correct. There being no merit in them, the cross-appeals are accordingly dismissed.
As background study, some of the technical testimony of the witnesses will be now summarized. The fertilizer plant was served by what is known as a 440 volt “delta-delta ungrounded three-phase” electrical system. Three-phase systems are commonly used for industrial power applications. Three wires, or “phases,” supply the motors which operate the machinery. All three of the wires are “hot,” and anyone coming in contact with any two of them simultaneously will be either shocked severely, or killed. This is especially true where higher potentials such as the 440 volts used in the fertilizer plant are involved, for the reason that the human body’s normally high resistance to the passage of an electric current will be more easily overcome by higher voltages. One hundred and ten volts, or less, may cause death by electrocution under some conditions. It is well known that the ground is a good conductor of electricity, particularly where it is damp and covered with hydroscopic mineral matter as was the condition in the Farmers Co-operative plant at the time of the accident. It should be observed that the plant’s circuit was described as an “ungrounded” system.
The testimony is to the effect that an ungrounded three-phase system under ordinary circumstances is not dangerous, and that a person standing upon the ground could touch any one naked wire of the system and experience nothing more than discomfort. The testimony is uncontradicted that two of the three wires serving the plant had become grounded, since two Kerney connectors in the switch room [by some means] had come in contact with the lid covering the metal trough in which they were located and had become “fused” into the cover, thus making excellent electrical contact with the ground. In this way, the ground had become a charged electrical conductor; and a person standing upon it could be electrocuted if he came in electrical contact with the third or ungrounded wire, as this would complete the circuit through such person’s body. Thus, the ungrounded *459and comparatively safe circuits had become grounded and consequently were more dangerous.
It is apparent that the metal frame of the portable conveyor which the decedents were engaged in turning around at the time of their electrocution had come in electrical contact with live wiring ; otherwise, the men would not have been electrocuted. The only evidence showing how that equipment could have become charged is the testimony of one of the witnesses for appellees to the effect that the insulation on the portable cable supplying its motor had burned, or “carbonized,” within a switchbox, providing a path which could be followed by the current to the metal frame of the conveyor.
The Kerney connectors referred to are metal devices used to connect heavy-gauge electric wiring that cannot be twisted together and soldered in the usual manner. In the switch room of the plant, there was a large junction box or trough which housed some of the wiring. Within that box the line wires were joined by Kerney connectors to load circuits carrying energy to various parts of the plant. This trough was wholly within the plant and under the control of those operating it. The Kerney connectors are uninsulated before their installation. After connections have been made, the electrician surrounds the joint with tape to form an insulating envelope. Several layers of rubber tape having high insulation value are first wrapped on. Friction tape is then applied over the insulating tape so as to protect the latter from mechanical damage. The connectors in the fertilizer plant were insulated in this manner and a metal cover or lid was then screwed over the trough. After the accident in which the decedents lost their lives it was discovered that the insulation on the Kerney connectors on two phases had broken down and the connectors had fused into the lid of the trough. As stated heretofore, this made good electrical contact with the ground rendering the plant’s electrical system unusually dangerous. The essential difference in the hypotheses of the parties is as to the cause of the breakdown of the insulation on these connectors. Appel-lees sought to introduce evidence that the breakdown was caused by excessive voltages negligently introduced from the appellants’ wires, while appellants insist that there was probably mechanical contact between the Kerney connectors and the lid caused by either faulty insulation or puncture of the insulating tape by the sharp corners of the connectors.
The appellees (plaintiffs) had the burden of proof which they attempted to carry by introduction of extensive testimony of expert witnesses, especially that of Walter I. Self, an electrical engineer. The opinion of an expert can achieve no higher dignity than is justified by the facts or assumptions upon which his opinion is based. It is necessary here to separate facts from assumptions and to determine whether the assumptions were based upon substantial evidence.
The hypothesis of the plaintiffs-appel-lees is that the fertilizer plant had been newly constructed, had been wired in accordance with the highest standards of the art, and had passed the scrutiny of the electrical inspectors of the State of Tennessee; and that, therefore, the breakdown of insulation was not caused by defects in the insulation but by a “surge” of high voltage from the appellants’ wires greatly exceeding the design limits of the plant’s wiring. The tape envelopes were removed from the connectors after the accident and were subjected to tests conducted at the University of Tennessee which supplied the required apparatus. Increasing voltages were applied to the insulating envelopes at points which had not been charred or burned. A breakdown of the insulation occurred at approximately 9,000 volts. On the basis of this experiment, expert witness Self concluded that this extreme voltage had entered the fertilizer plant wiring which was designed to earry only 440 volts. His conclusion necessarily assumes that the insulation *460value at the points tested was the same as the value at the points where the tape had been destroyed. A' test of the charred places would be meaningless now.
The accuracy of Self’s assumption is doubtful, as the testimony shows that a breakdown would have occurred at the weakest point in the insulation. Therefore, the points tested must have been better insulated than those which broke down. The testimony of the installing electricians that the insulation was sufficient and the Tennessee Electrical Inspector’s' assertion that he had approved the installation are not material here, inasmuch as this testimony related only to the condition of the wiring before the lid was tightened down on the trough some three weeks prior to the accident, There was no testimony relating to insulation resistance measurements, or “megger tests,” made before the accident, so it cannot be stated accurately whether or not the insulation was damaged when the cover was attached or what its condition was at the time of the breakdown.
The validity of Self’s conclusion, moreover, depends upon the truth of other assumptions. He must assume that the appellants’ hypothesis is incorrect; that is, that there was no mechanical breakdown of the insulation. A further assumption made by Self was revealed upon cross-examination. Without making any tests, the witness had concluded that the surge-proof features and lightning arresters were defective on the three step-down transformers from which the plant is served, for these devices would have drained off most of such a surge to ground. He based this assumption on the “fact” that 9,000 volts had entered the plant.' This “fact,” as we have seen, ís in reality only an opinion which ap-pellees are required to elevate to the status' of evidence by' proving the truth of Assumptions upon which it is based, The assumption may not be proved by the conclusion sought to be drawn.
' it' was assumed, also, that switching operations were in progress at the time of the accident. The testimony is that all the members of the line crew were in the office at least twenty-five minutes before the accident and did not leave until some time after the electrocution. There is uncontroverted testimony that the last switches were thrown by the line crew prior to 7:00 A. M., nearly one hour be-^ore the accident, which occurred at 7:50 A. M.
To controvert this opinion of the expert, Self, based upon unsupported assumptions, appellants introduced direct evidence that in fact no such extreme voltages had been on the lines of the utility. The T. V. A. maintains an oscil-lograph capable of recording surges having a duration of only microseconds, whether the surge comes from its own lines or from the lines of the appellants. There were no recorded indications of such a “surge” near the time 0f the accident. Several expert witnesses also testified, without contradietion, that had such voltages gotten into the wires of the utility, light bulbs, clocks, and other small appliances throughout the. Maryville area would have burned out instantly. There is no evidence of any such burned-out elements, and there is direct evidence that the electric clock and appliances of the plant are still operative,
The testimony demonstrates not only that there was no surge, but also that there is no possible source of a surge of the magnitude asserted by the plaintiffs-appellees. The expert, Self, states that a surge could have come in, “* * * either from-lightning or what is commonly known to the industry as a switching surge.” The possibility of lightning was ruled out by uncontroverted testimony by the weather man. The possibility of a “switching surge” alone remains. ,
A switching surge originates in a-transformer. Transformers can store energy within the iron core so that if power supply is interrupted the stored energy may sometimes- be dissipated throughout the systém' in a surge of induced voltage considerably higher *461than that usually carried. The amount of voltage dissipated in this manner will depend upon the characteristics of the transformer, particularly its power-carrying capacity. Witness Self testified that in order to produce a discharge, or surge, of the magnitude assumed here, a transformer of the 1,000 K. V. A. size, or larger, would fee required. The evidence is uncontroverted that nowhere in the appellants’ transmission system is there any transformer having this rating. It would have been impossible, therefore, for the appellants to cause even deliberately a switching surge similar to one which appellees contend was negligently transmitted into the fertilizer plant.
Appellees charge further that the appellants w’ere negligent in maintaining their transmission system and equipment in a dangerous and defective condition. The only evidence alleged to support this charge pertains to certain circuit reclosers located in the lines between the Maryville sub-station and the transformers at the fertilizer plant. A recloser serves the same function as a fuse in household wiring, but is more complicated. When a short circuit or overload causes an excessive amperage to pass through, the recloser will open the circuit to protect wires and equipment. High percentages of transmission line overloads are temporary and self-clearing, such as difficulties caused by wind-blown tree branches brushing over the wires. For this reason, the recloser is designed to close the circuit again after a short period of time so that power will quickly be restored automatically. If the difficulty persists, the re-closer will reopen and then will “test” the circuits by closing two more times. If the difficulty still exists at the completion of these three cycles of operation, the recloser will go to “lock out” position, cutting off the power until the re-closer is reset. In order to restore service, the line crew must locate and correct the difficulties that cause the re-closer to open. They then close it manually. Appellants’ lines were protected by three of these reclosers, one on each of the three phases.
Inasmuch as one of the customers of the appellants used three-phase power, appellees insist that proper practice requires the use of one “three-phase” re-closer at this point instead of three single-phase reclosers. The former piece of equipment has the three reclosers mechanically interconnected so that if the element on any ®ne of the phases goes through its three cycles to lockout position, the power will be cut off on the other two phases. This feature is to protect three-phase motors from burning out as the result of a “single-phase” condition. Single phasing introduces no additional hazards to personnel using the equipment.
The evidence shows that one of these reclosers had begun a cycle of operation and had jammed in the open position before it reached the lockout condition. The operating arms on the reclosers indicated that they were in the closed position, but the position of the arm is not conclusive. The only sure test is whether or not current is flowing through; and the evidence conclusively shows that power had been interrupted. Voltmeter tests indicated this, as did the fact that after the accident the outage or single-phase condition was cured by “strapping around” the reeloser — that is, by bypassing it with a “jumper” or shunt wire. Thus, the recloser had done just what it was supposed to do in regard to disconnecting the circuit for the protection of the equipment. The only defective operation was that it had failed to restore power automatically to the circuit. Under these circumstances, it is inconceivable that either the malfunctioning recloser or the failure of the utility to inspect and conduct routine maintenance on that piece of equipment could be the direct and proximate cause of the accident. A dead electrical circuit can harm no one.
The evidence shows that the surge contemplated by expert witness Self was of very short duration, a few microseconds. There is nothing to contradict *462testimony that a recloser in perfect condition would not function with sufficient speed to interrupt such a surge. This would be true of three-phase and single-phase reclosers alike. The conclusion is inescapable that these reclosers could not have been the proximate cause of this electrocution, as there would have been no difference in result if the single-phase recloser actually in service at the time had been in perfect operating condition, or if one three-phase recloser had been in use instead of three single-phase reclosers.
Appellees contend that appellants were negligent in failing to warn plaintiffs’ decedents or their employer of the defective condition existing in its transmission lines. We have already observed that, as demonstrated by the evidence, only a “single-phase condition” existed at the time of the accident and that this condition introduced no additional hazards to personnel, inasmuch as a normally live wire which has become dead is harmless. Even if this were not so, the uncontradicted testimony is that the personnel of the fertilizer plant, including its electrician, had actual notice of the single-phase condition of the appellants’ wires. There is no question about this, inasmuch as the fertilizer plant reported the outage to the utility only seconds before the accident.
Appellees cite extensive authority to the effect that power to all customers should have been shut off immediately when it was discovered that an irregular condition existed on its lines. All the cases cited are distinguishable upon their facts. Most of them disclose situations where live wires have fallen and the utility had notice of this dangerous condition. E. g. Dabbs v. Tennessee Valley Authority, 1952, 194 Tenn. 185, 250 S.W.2d 67. One case related to a company which failed to shut off its power when notified that a fire was raging below its high tension wires. Osborne v. Tennessee Electric Power Co., 1929, 158 Tenn. 278, 12 S.W.2d 947. In another, the defendant had notice that wires were sparking and causing flashes of fire in close proximity to a building. Virginia Electric & Power Co. v. Carolina Peanut Co., 4 Cir., 1951, 186 F.2d 816. In our judgment, these cases are in no way analogous.
In the instant situation, the defendant utility had no notice of a dangerous situation. There was only an open circuit or outage somewhere in its system, a condition which does not usually imply danger. Upon receiving complaint of this, linemen were dispatched to ascertain the trouble. A visual inspection was made of all lines and at least an hour before the accident several poles were climbed in order to-make tests. No dangerous conditions were discovered then or at anytime thereafter. Where a utility has no notice of a dangerous condition and has. made an inspection which reveals no-hazardous situation, there is no duty to-shut off the power to all customers. Judicial notice may be taken that an unwarranted interruption of power may cause serious and unnecessary economic loss and possibly even loss of life.
For the foregoing reasons, our judgment is that the verdicts of the jury are not supported by substantial evidence. The judgments are, therefore, reversed and the causes remanded to the-district court with instructions to sustain the motions of defendants for judgments non obstante veredicto, dismissing the complaints.