TN LLE HVAC and Air-Conditioning Circuits 2

Question 1

According to NEC Article 440, what is the maximum allowable voltage drop for the branch circuit supplying an air-conditioning compressor?

Accepted Answer

No specific limit in Article 440

Answer

NEC Article 440 does not specify a maximum voltage drop for branch circuits supplying compressors. Voltage drop recommendations are found in informational notes throughout the NEC.

Question 2

What determines the minimum branch-circuit conductor size for a single hermetic refrigerant motor-compressor per NEC 440.32?

Accepted Answer

The nameplate rated-load current

Answer

Per NEC 440.32, the branch-circuit conductor size for a single motor-compressor must not be less than 125% of the rated-load current OR the branch-circuit selection current, whichever is greater.

Question 3

When an air-conditioning unit has both a compressor motor and a fan motor, how is the overcurrent protection device sized?

Accepted Answer

Based on the compressor rated-load current plus the full-load current of other motors, with OCPD sized per the largest motor's table value

Answer

The OCPD is sized using the largest motor's maximum rating from the applicable table, plus the sum of the rated-load or full-load currents of all other motors in the circuit.

Question 4

What is the maximum distance a disconnecting means for an air-conditioning unit can be located from the equipment per NEC 440.14?

Accepted Answer

Within sight from and readily accessible

Answer

NEC 440.14 requires the disconnecting means to be within sight from and readily accessible from the air-conditioning or refrigerating equipment.

Question 5

A room air conditioner connected to a 120-volt, 15-ampere branch circuit must not exceed what percentage of the circuit rating per NEC 440.62(B)?

Accepted Answer

80%

Answer

Per NEC 440.62(B), a room air conditioner rated 120 volts shall not exceed 80% of the branch-circuit ampere rating if other outlets are also supplied.

TN LLE - Tennessee Limited Licensed Electrician Practice Test

TN LLE - Tennessee Limited Licensed Electrician Practice Test

TN LLE HVAC and Air-Conditioning Circuits 2