The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 14, 1993
Filed:
Nov. 14, 1991
Thomas M McDonald, Monroe, CT (US);
W Reid Smith-Vaniz, Darien, CT (US);
Hubbell Incorporated, Orange, CT (US);
Abstract
A personnel protection system for electrical connections is disclosed, which is of the type that differentially senses the current flow between the power lead and the return lead (or between two power loads) is provided with an unbalancing impedance which makes the current difference between the two leads sufficiently high to trip the device and cause the power to be disconnected. A utilization device is similarly provided with an imbalanced impedance. However, that impedance is calculated to counteract the current imbalance caused by the first impedance, so that when the cable is connected to the utilization device, the current balance between the two conductors is restored, and power connection is maintained in the cable. In addition, the current flow in the second impedance is sensed and, if it is not at the correct level, electrical power to the load is disconnected in the same manner as when an imbalance occurs. Thus, the system does not provide continuous power unless predetermined conditions considered safe for securing the power are fully satisfied.