Chat with AIExam 13: The Electric Service and Grounding
What is an effective ground-fault current path?
(79) 
Verified
An effective ground-fault current path is an intentionally constructed, low-impedance electrically conductive path designed and intended to carry current under ground-fault conditions from the point of a ground fault on a wiring system to the electrical supply source and that facilitates the operation of the overcurrent protective device or ground-fault detectors on high-impedance grounded systems. If and when a ground fault occurs, we want the overcurrent device ahead of the ground fault to open as fast as possible to clear the fault. To accomplish this, the integrity of the ground fault current path must be unquestionable.
The ____ is defined in NEC Article 100 as the point of connection between the facilities of the serving utility and the premises wiring .
(77) VerifiedC
What liquid was used in the past in liquid-filled transformers? Is it still in use?
(78) VerifiedYears ago, the most widely used liquid was askarel, a mixture of polychlorinated-biphenyls (PCBs)and trichlorobenzene-found to be highly toxic. Askarel was good for indoor installations because it was not flammable, it had excellent insulating characteristics and cooling features, and the cost was attractive. The Toxic Substance Control Act of 1976 and further regulations set forth by the Environmental Protection Agency (EPA)pretty much made askarel a thing of the past. These older transformers have either been replaced over the years or have had the askarel (the PCB liquid)removed and then replaced with noncontaminating liquids.
The lower (or shorter)the ____ of the grounding path, the greater the ground-fault current.
(75) Utilities make up the connections on the line side and load side of their transformers according to the ____ requirements.
(89) The temperatures of an electrical arc, such as might occur on a 480/277-volt solidly grounded, wye-connected system, are ____.
(85) The ____ connection scheme has the advantage of being able to provide either 3-phase or 3-phase and single-phase power using only two transformers.
(89) In this country and throughout the world, ____ is(are)the common reference point for all electrical systems.
(76) ____ occur when an ungrounded "hot" conductor comes in contact with a grounded surface or grounded equipment.
(66) GFCI protection can be attained using GFCI circuit breakers or GFCI ____.
(92) NEC 230.71 permits not more than ____ disconnects to serve as the building disconnecting means.
(67) The two basic methods of metering are primary high-voltage metering and ____.
(75) NEC 250.64(C)states that grounding electrode conductors generally are not permitted to be ____.
(84) Today's liquid-filled transformers have their windings immersed in highly refined mineral oil (combustible), silicone fluid, edible seed oil-based dielectric coolant, or other acceptable nontoxic liquids that have ____ properties.
(73) Dry-type transformers are widely used because they are ____ than comparably rated liquid-filled transformers.
(68) NEC 110.16 has a requirement for placing a notice on certain equipment to warn qualified persons of the serious hazard of ____ flash events.
(71) 
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