When a cord-connected window air conditioner is the only connected load, the current drawn shall not exceed what percent of the branch circuit rating?

When a cord-connected window air conditioner is the only connected load, the current drawn shall not exceed what percent of the branch circuit rating?

• A. 50
• B. 100
• C. 80
• D. 125

Answer: (C)

The test is about how much of a branch circuit you can continuously load with a single cord-connected appliance. For a load that runs for extended periods, you don’t want to pull the full circuit rating continuously. So the rule is to keep the running current at or below 80% of the branch-circuit rating. A cord-connected window air conditioner, when it’s the only load on that circuit, is treated as a continuous-type load, which is why the 80% limit applies. For example, on a 15-amp circuit, 80% is 12 amps. If the air conditioner’s running current stays at or under about 12 amps, the installation complies. If it would exceed that, you’d need a larger circuit or a dedicated circuit to handle the load and its startup surge. Why the other options don’t fit: using only 50% would be unnecessarily restrictive, 100% would allow operating at the full circuit rating which isn’t safe for continuous loads, and 125% isn’t the rule for this situation.

The test is about how much of a branch circuit you can continuously load with a single cord-connected appliance. For a load that runs for extended periods, you don’t want to pull the full circuit rating continuously. So the rule is to keep the running current at or below 80% of the branch-circuit rating. A cord-connected window air conditioner, when it’s the only load on that circuit, is treated as a continuous-type load, which is why the 80% limit applies.

For example, on a 15-amp circuit, 80% is 12 amps. If the air conditioner’s running current stays at or under about 12 amps, the installation complies. If it would exceed that, you’d need a larger circuit or a dedicated circuit to handle the load and its startup surge.

Why the other options don’t fit: using only 50% would be unnecessarily restrictive, 100% would allow operating at the full circuit rating which isn’t safe for continuous loads, and 125% isn’t the rule for this situation.