Special-Purpose Outlets- Water Pump, Water Heater--part 6: QUIZ

Note: Refer to the Code or the plans where necessary.

WATER PUMP CIRCUIT

1. Does a jet pump have any electrical moving parts below the ground level?

2. Which is larger, the drive pipe or the suction pipe?

3. Where is the jet of the pump located?

4. What does the impeller wheel move?

5. Where does the water flow after leaving the impeller wheel?

a.

b.

6. What prevents water from draining back into the pump from the tank? ________.

7. What prevents water from draining back into the well from the equipment?

8. What is compressed in the water storage tank?

9. Explain the difference between a "2-wire" submersible pump and a "3-wire" submersible pump.

10. What is a common speed for jet pump motors? 11. Why is a 240-volt motor preferable to a 120-volt motor for use in this residence? 12. How many amperes does a 1-horsepower, 240-volt, single-phase motor draw? (See Table 430.248.)

13. What size are the conductors used for this circuit?

14. What is the branch-circuit protective device?

15. What provides the running overload protection for the pump motor?

16. What is the maximum ampere setting permitted for running overload protection of the 1-horsepower, 240-volt pump motor?

17. Submersible water pumps operate with the electrical motor and actual pump located (circle the correct answer)

a. above permanent water level.

b. below permanent water level.

c. half above and half below permanent water level.

18. Because the controller contains the motor starting relay and the running and starting capacitors, the motor itself contains ___.

19. What type of pump moves the water upward inside of the deep-well pipe?

20. Proper pressure of the submersible pump system is maintained by a ___.

21. Fill in the data for a 16-ampere electric motor, single-phase, no Code letters.

a. Branch-circuit protection, non-time-delay fuses:

Normal size __A Maximum size __A

Switch size __A Switch size __A

b. Branch-circuit protection dual-element, time-delay fuses:

Normal size __A Maximum size __A

Switch size __A Switch size __A

c. Branch-circuit protection instant-trip breaker:

Normal setting __A

Maximum setting __A

d. Branch-circuit protection-inverse time breaker:

Normal rating __A

Maximum rating __A

e. Branch-circuit conductor size, Type THHN __Ampacity __A

f. Motor overload protection using dual-element time-delay fuses:

Maximum size __A

22. The NEC is very specific in its requirement that submersible electric water pump motors be grounded. Where is this specific requirement found in the Code?

23. Does the NEC allow submersible pump cable to be buried directly in the ground?

24. Must the disconnect switch for a submersible pump be located next to the well?

25. A metal well casing (shall) (shall not) be bonded to the pump's equipment grounding conductor or by grounding it with a separate equipment grounding conductor run all the way back to the same ground bus in the panelboard that supplies the pump circuit, NEC _____

WATER HEATER CIRCUIT

1. According to 422.47 the high-temperature limit control must disconnect ___ of the ungrounded conductors. The high-temperature control limits the maximum water temperature to ___ 8F (__ 8C).

2. A major hazard involved with water heaters is that they operate under whatever pres sure the serving water utility supplies. Water stays liquid at temperatures higher than the normal boiling point of 2128F (1008C). If the high-temperature limit control failed to operate for whatever reason, should a pipe burst or a faucet be opened, the pressure would instantly drop to normal atmospheric pressure, causing the superheated water to turn into ______ that could result in _______. To prevent this from happening, water heaters are equipped with pressure/temperature relief valves.

3. Magnesium rods are installed inside the water tank to reduce ________.

4. The heating elements in electric water heaters are generally classified into two categories. These are ______ density and ______ density elements.

5. An 80-gallon electric water heater is energized for the first time. Approximately how many hours would it take to raise the water temperature 808F (26.678C) (from 408F to 1208F [4.448C to 48.898C])? The water heater has a 3000-watt heating element.

6. What term is used by utilities when the water heater power consumption is measured using different rates during different periods of the day?

7. Explain how the electric utility in your area meters residential electric water heater loads.

8. For residential water heaters, the Consumer Product Safety Commission suggests a maximum temperature setting of ______ 8F ( _____8C).

Some states have laws stating a maximum temperature setting of ______ 8F ( ____ 8C).

9. An 80-gallon electric water heater has 608F (15.568C) incoming water. How many minutes can a 3-gallon/minute showerhead be used to draw 1058F (40.568C) water if the water heater thermostat is set at 1208F (48.898C)? ____.

10. Approximately how long would it take to produce serious burns to an adult with 1408F (608C) water? _______

11. Two thermostats are generally used in an electric water heater.

a. What is the location of each thermostat?

b. What type of thermostat is used at each location?

12. a. How many heating elements are provided in the heater in the residence discussed in this text?

b. Are these heating elements allowed to operate at the same time?

13. When does the lower heating element operate?

14. The Code states that water heaters having a capacity of 120 gallons (450 L) or less shall be considered _____ duty and, as such, the circuit must have a rating of not less than __ percent of the rating of the water heater.

15. Why does the storage tank hold the heat so long?

16. The electric water heater in this residence is connected for "limited demand" so that only one heating element can be on at one time:

a. What size wire is used to connect the water heater?

b. What size overcurrent device is used?

17. a. If both elements of the water heater in this residence are energized at the same time, how much current will they draw? (Assume the elements are rated at 240 volts.)

b. What size and Type THHN wire is required for the load of both elements? Show calculations.

18. a. How much power in watts would the two elements in Question 17 use if connected to 220 volts? Show calculations.

b. What is the current draw at 220 volts? Show calculations.

19. A condominium owner complains of not getting enough hot water. The serviceman checks the voltage at the water heater and finds the voltage to be 208 volts. The serviceman checks further and finds the electrical service on the building to be a 120/ 208-volt, three-phase, 4-wire system. The main electrical panelboard for each condominium unit is fed with a 3-wire supply. The nameplate on the electric water heater is marked 4500 watts, 240 volts. What is the wattage output of the heating element in this water heater when connected to a 208-volt supply?

20. For a single, nonmotor-operated electrical appliance rated greater than 13.3 amperes that has no marking that would indicate the size of branch-circuit overcurrent device, what percentage of the nameplate rating is used to determine the maximum size branch-circuit overcurrent device?_________

21. A 7000-watt resistance-type heating appliance is rated 240 volts. What is the maxi mum size fuse permitted to protect the branch-circuit supplying this appliance?

22. The Code requirements for standard resistance electric water heaters are found in Article 422 of the Code. Because heat pump water heaters contain a hermetic refrigerant motor compressor, the Code requirements are found in Article of the Code.

23. In your area, is the branch-circuit breaker or switch for the electric water heater branch circuit acceptable as the disconnecting means, or are you required to install a separate disconnect within sight of the water heater? Provide a brief explanation.