The opinion of the court was delivered by
Pashman, J.This is a companion case to Watson v. Nassau Inn, 74 N. J. 155 (1977) and Briggs v. American *178Biltrite, 74 N. J. 185 (1977). The sole issue is compensability, defendant having conceded petitioner’s total disability. The judge of compensation granted petitioner’s claim but the Appellate Division reversed, holding that “the matter falls clearly within the going and coming rule.” The appeal is before us as of right because of Judge Kole’s dissent. R. 2:2-1 (a) (2).
The pertinent facts are not in dispute. The petitioner, William Paige, was one of two chief water plant operators in the Water Department of the City of Rahway. The water treatment plant operated around the clock and was manned continuously by a shift operator. Petitioner and his fellow chief operator alternated weekly in working on the 8 a.m. to 4 p.m. shift and the 4 p.m. to midnight shift. Their duties included supervision of department personnel, organization of work schedules, maintenance of plant machinery and keeping records of operations. The chief operator worked under the assistant superintendent of the department during the daytime shift, but he was in complete charge during the night shift.
Because there was no third supervisor for the midnight to 8 a.m. shift, one of them also had to remain on call during that shift and to take responsibility for any emergencies which might arise. Petitioner’s supervisor testified that as a chief operator, he was theoretically on call 24 hours a day, 7 days a week, as are policemen and firemen. This duty was formally incorporated into the civil service description of the job, and petitioner received no extra compensation for the additional weekday shift unless he was required to make a call.1 However, the supervisor added that petitioner’s “on call” status was, in practical terms, limited to this *179midnight to 8 a.m. shift on specified weeks and to alternate weekends. The department left it to the two men to determine when they would be on duty. They agreed between themselves that the man assigned to the evening 4 p.m. to midnight shift would also take responsibility for the following midnight to 8 a.m. shift.
Since the consequences of a breakdown in the water treatment system would have been serious, performance of this on call duty was critical to the operations of the plant. The superintendent of the department testified that petitioner was expected to inform the plant if he left home for more than a few minutes, and petitioner himself stated that he always left a telephone number and address where he could be reached. He also said that he did not travel any substantial distance out of town when he was on call.
There was also evidence that petitioner had separate responsibilities in addition to this bi-weekly on call duty. On various occasions when the water pressure fluctuated (usually in the summer months), he was required to make adjustments of certain interconnections located throughout the city. These adjustments were made with a valve key, a large, bulky tool with a lever arrangement. The department had a truck equipped with the necessary tools, but he kept his own valve key in the trunk of his car so that he could drive directly to the interconnections and avoid making a trip to the plant. He did this with the approval of his superiors, one of whom also carried a valve key in his car to save time in making the same adjustments.
The injuries which led to this claim for workers’ compensation benefits were caused by an unknown assailant who attacked petitioner just after he arrived home from work on the evening of January 18, 1972. Petitioner had been on duty during the 4 p.m. to midnight shift that night and he had just dropped off the shift operator at his home. He then returned to his own home where he was scheduled to remain on call for the next eight hours. The particular details of the assault could not *180be fully established before the compensation judge because petitioner’s memory was impaired by the beating. Nevertheless, defendant conceded that the attack must have occurred immediately after petitioner locked his car in the driveway. He was robbed and beaten severely, suffering a depressed skull fracture, brain impairment and a significant hearing loss. He subsequently fell and fractured his right shoulder during a seizure which occurred while he had a temporary plate in his skull. Defendant has not challenged the finding, that these injuries constituted total disability.
We agree with the legal conclusion of the judge of compensation that petitioner’s injuries occurred in the course of his employment and therefore entitle him to workers’ compensation benefits under N. J. S. A. 34:15-7. Although the judge stressed in his decision the particular factual setting surrounding this tragic assault,2 we think that the nature of petitioner’s on call status is a sufficient basis for providing recovery. The rationale for the going and coming rule is the suspension of the employment relationship after the employee’s departure from work at the end of the day, see Gullo v. American Lead Pencil Co., 119 N. J. L. 484, 486 (E. & A. 1937); Gilroy v. Standard Oil Co., 107 N. J. L. 170, 172 (E. & A. 1930). Since petitioner’s on call status obligated him to his employer even after he left his place of work, the rule obviously has no application here as a bar to compensation. Petitioner was under direct instructions to inform the plant of his whereabouts during the midnight to 8 a.m. shift and to remain available for emergency calls. He was personally accountable for the operation of the plant and could be interrupted at any time. He *181took these responsibilities seriously as an integral part of his job and remained, as the compensation judge found, “on a rather tight leash” during these stand-by periods; It is clear that petitioner’s trip home at that hour and his location at the time of the assault were both within the contemplation of his employer. See Bryant Adm’x v. Fissell, 84 N. J. L. 72, 77 (Sup. Ct. 1913).
In addition, the city received a substantial benefit from this working arrangement, since it could dispense with the need for a third chief operator to supervise the midnight to 8 a.m. shift. Moreover, as the compensation judge noted, the city was relieved of the cost of providing suitable sleeping quarters at the plant for the chief operator during this shift. It would be contrary to the underlying purposes of workers’ compensation to force the employee to absorb the risks of this extra duty simply because he returned home. See Watson v. Nassau Inn, supra, 74 N. J. at 159; Briggs v. American Biltrite, supra, 74 N. J. at 188-189.
These facts distinguish petitioner’s position from other jobs whose formal descriptions also contain a requirement that the employee be on call for emergencies at all times. In Jasaitis v. Paterson, 31 N. J. 81 (1959), we upheld an award of benefits to a policeman injured on his way home from work. Significantly, we emphasized his specific duties while in uniform and the public benefits of his visible’ presence as a deterrent to crime, rather than his on call status around the clock. Id. at 85-86. Cf. Robinson v. Levy, 20 N. J. Misc. 444 (W. C. B. 1942); Juna v. New York State Police, 40 A. D. 2d 742, 336 N. Y. S. 2d 738 (1972); Donnell v. Waccacbuc Country Club, 29 A. D. 2d 1022, 289 N. Y. S. 2d 534 (1968). By contrast, in Morris v. Hermann Forwarding Co., 18 N. J. 195 (1955), we denied compensation where the claimant’s home activities were limited to occasional telephone calls to his employer. Id. at 200. It makes no difference here that petitioner’s injuries did not stem directly from an emergency trip to the plant. As in Jasaitis, his off duty time was not his own because he re*182mained subject to well defined limitations dictated by his employer. In fact, this case is stronger than Jasaitis because petitioner’s readiness for immediate service was critical to the safe and efficient operation of the plant.
Defendant’s argument that the assault did not “arise out of” petitioner’s employment is without merit. We have found that petitioner’s employment extended to his trip home so that he was still in the course of employment when attacked; thus it would not have occurred “but for” his employment. See White v. Atlantic City Press, 64 N. J. 128, 139 (1973); Howard v. Harwood's Restaurant Co., 25 N. J. 72, 82 (1957). Absent any proof that the assault was motivated purely by personal animus unrelated to petitioner’s employment, see Pittel v. Rubin Bros. Bergen Co., 59 N. J. Super. 531 (App. Div. 1960) the requisite causal connection is established under the “positional risk”3 test which we have adopted. See, e. g., White v. Atlantic City Press, supra.
The judgment of the Appellate Division is reversed, and the decision of the judge of compensation is hereby reinstated.
During the weekends when he was on call, petitioner received overtime pay simply for being available. On those occasions when he was required to go to the plant, he was paid for a least two hours work, at the appropriate overtime rate, with additional compensation for any other hours actually worked.
He mentioned, in particular, the late hour at which petitioner was assaulted, the use of his personal car for emergency tasks and the presence of work tools in his car at the time of the assault. Cf. Rubeo v. Arthur McMullen Co., 117 N. J. L. 574 (E. & A. 1937) ; Pisapta v. Newark, 47 N. J. Super. 353 (Cty. Ct. 1957).
See Briggs v. American Biltrite, 74 N. J. 185, 189 (1977).