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What are the three circuit breaker ( overcurrent protection device) categories?
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A qualifying term indicating that no delay is purposely introduced in the tripping action of the circuit breaker.
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Codeology 4
Codeology 3 Lesson 4
| Question | Answer |
|---|---|
| What are the three circuit breaker ( overcurrent protection device) categories? | 1. Branch-circuit OCPDs 2.Application limited OCPDs 3.Supplementary OCPDs, suitable for specific branch-circuit applications, under limited conditions |
| A qualifying term indicating that no delay is purposely introduced in the tripping action of the circuit breaker. | Instantanious Trip |
| A qualifying term indicating that the circuit breaker can be set to trip at various values of current, time, or both, within a predetermined range. | Adjustable |
| A qualifying term indicating that the circuit breaker does not have any adjustment to alter the value of current at which it will trip or the time required for its operation. | nonadjustable |
| A qualifying term indicating that there is purposely introduced a delay in the tripping action of the circuit breaker, which delay decreases as the magnitude of the current increases | inverse Time |
| The value of current, time, or both, at which an adjustable circuit breaker is set to trip. | Setting |
| Which is not a category for overcurrent devices? a.Application limited OCPDs suitable for specific branch-circuit applications, under limited conditions b. Branch-circuit OCPDs c. Nonautomatic OCPDs d. Supplementary OCPDs | Nonautomatic OCPDs |
| Insulated Case Circuit Breakers | 489 |
| Low-Voltage Power Circuit Breakers | 1066 |
| Molded Case Circuit Breakers | 489 |
| Motor Circuit Protectors | 489 |
| Supplementary Protectors | 1077 |
| Low-voltage power circuit breakers are the most rugged, highest priced, and largest size circuit breakers and are used in larger ampacity circuits in main switchgear and unit substations. | true |
| Test The operating mechanism, including the handle, opens or closes the circuit breaker contacts. | true |
| Test The characteristic of the operating mechanism in using the handle to open or close a circuit breaker is referred to as quick-make, quick-break as to prevent the breaker from being able to be “teased” from OFF-to-ON or ON-to-OFF | True |
| Most circuit-breaker terminal connectors are rated ? a. 60°C b. 75°C c. 90°C d. both a. and b. | d. both a. and b. |
| Part of the process of a circuit breaker interrupting an overcurrent is that the trip unit senses the overcurrent, and releases or unlatches the contacts. This then permits the movable ? to start to travel or part from the stationary contact. | contact |
| Test A circuit breaker’s current sensing trip unit can be ? a. electronic b. magnetic only c. thermal magnetic d. any of the above | d. any of the above |
| What is/are the common operating function(s) that mechanical OCPDs share? a. Current/voltage interruption means b. Current-sensing means c. Unlatching mechanism d. All of the above | d. all of the above |
| The operating characteristics of an OCPD trip curve can be visually displayed in a ? curve | Time current |
| Test Electronic trip units can offer ? accuracy, additional trip adjustments, programming, and communication. | increased |
| The long-time pick-up (LTPU) and long-time delay (LTD) determine the overload protection characteristics of an adjustable electronic circuit breaker. The typical adjustment range for the LTPU is from ? times the circuit-breaker ampere rating. a. 0.25 | 0.5 to 1.0 |
| Current-limiting circuit breakers can be ? a. inherently current-limiting in their design b. internally fused c. both a. and b. d. neither a. nor b. | c. both a. and b. Correct |
| How can it be determined if a circuit breaker is current-limiting? a. All 200 A or less circuit breakers are current-limiting b. It will be marked “Current-Limiting” c. It will have an interrupting rating greater than 10kA d. None of the above | It will be marked “Current-Limiting” Correct |
| What devices are permitted to be used as branch circuit OCPDs in service, feeders, and branch circuits? | Molded Case Circuit Breakers (MCCBs) |
| A circuit breaker with a special “straight” rating of 277/480 volts may be used on a corner-grounded delta system. | False Note: “Straight” rated circuit breakers are rated at 240, 480, or 600 volts and not 277/480 volts; which is a slash rating |
| Interrupting ratings on AC rated circuit breakers are used for ? . Select one: a. AC systems only b. DC systems only c. both AC and DC systems d. none of the above | AC systems only |
| A Type ICCB uses electronic sensor technology | True |
| What is the interrupting rating for LVPCBs? Select one: a. From 0 kA to 100,000 kA b. From 25 kA to 300,000 kA c. From 42 kA to 200 kA d. From 100 kA to 300 kA | c. From 42 kA to 200 kA |
| A specific MCP (motor circuit protector) can only be utilized with a motor starter that is listed for use with that MCP. | True |
| Supplementary overcurrent protection is used for luminaires, appliances, and other equipment and can be used as a substitute where branch-circuit overcurrent devices are required. | False |
| Which type of circuit breaker is designed to be reconditioned? Select one: a. Insulated case circuit breakers b. Low-voltage power circuit breakers c. Molded case circuit breakers | b. Low-voltage power circuit breakers Correct |
| Which is/are sources of circuit breaker maintenance information? I. Circuit breaker manufacturers’ manuals II. NETA Maintenance Testing Specification for Electrical for Electrical Power distribution Equipment and Systems. III. NFPA 70B Recommended Pr | b. I., II., and III. Correct |
| Quite often, a circuit breaker will be marked with multiple voltage ratings and the corresponding interrupting ratings for each voltage rating, such as 600-volt 14 kA interrupting rating, 480-volt 22 kA, and 240-volt 42 kA. | True |
| NFPA 70E 225.3 Circuit Breaker Testing states that “Circuit breakers that interrupt faults approaching their ratings shall be inspected and tested in accordance with the manufacturer’s instructions.” | True |
| A motor circuit protector (MCP) or instantaneous trip circuit breaker is a device that ? b. is part of listed combination with specific starter(s) c. is UL recognized d. provides no overload protection e. all of the above | e. all of the above |
Created by:
Shawnt321