CRD Geothermal System Controls, Electrical & Auxiliary Components 2

Question 1

Which NEC-required electrical protection device is mandatory for geothermal heat pump equipment installed in wet or damp locations?

Accepted Answer

Ground fault circuit interrupter (GFCI)

Answer

Arc fault circuit interrupter (AFCI)

Answer

Whole-house surge protector

Answer

Isolation transformer

Question 2

What type of wiring installation is required for geothermal ground loop electrical connections that transition from underground to inside the building?

Accepted Answer

Direct burial-rated cable or appropriate conductors in listed conduit

Answer

Standard residential NM-B cable run along the foundation

Answer

Low-voltage thermostat wire rated for 24V

Answer

THHN conductors run in open air above the ground surface only

Question 3

What electrical component is most effective at protecting geothermal heat pump electronics from utility power surges and voltage transients?

Accepted Answer

Type 2 surge protective device (SPD) at the panel

Answer

Time-delay fuse at the disconnect

Answer

Hard start capacitor kit

Answer

Capacitor bank for power factor correction

Question 4

What is the primary purpose of a hard start kit (potential relay and start capacitor) used with geothermal heat pump compressors?

Accepted Answer

To reduce locked rotor amperage and provide extra torque during compressor start-up

Answer

To prevent the heat pump from starting during high utility demand periods

Answer

To provide emergency backup power during electrical outages

Answer

To sequence multiple heat pump units to prevent simultaneous starts

Question 5

What is the standard control voltage used in residential geothermal heat pump low-voltage wiring between the thermostat and air handler?

Accepted Answer

24V AC

Answer

12V DC

Answer

48V DC

Answer

120V AC

Question 6

During geothermal system commissioning, which electrical measurement is most critical for verifying proper compressor operation?

Accepted Answer

Running amperage of the compressor compared to nameplate full-load amps

Answer

Supply voltage measured at the main electrical panel only

Answer

Power supply frequency measured at the unit disconnect

Answer

Power factor at the utility revenue meter

Question 7

In a residential geothermal installation, why is it important to verify that the circuit breaker size matches the unit's Maximum Overcurrent Protection (MOP) rating on the nameplate?

Accepted Answer

Correct breaker sizing ensures adequate short circuit and overload protection without nuisance tripping

Answer

Oversized breakers save energy by reducing voltage drops

Answer

The MOP rating determines the minimum wire gauge only

Answer

Breaker size affects the COP rating of the heat pump