In notification circuit design, the maximum allowable voltage drop due to conductor resistance is generally limited to ____ of the source voltage.

Question: In notification circuit design, the maximum allowable voltage drop due to conductor resistance is generally limited to ____ of the source voltage.

Answer options:

• 5%
• 10% ✅ 20%
• 30%

Correct answer: 20%

Explanation: S524 6.2.2.2 states that the calculations shall ensure that the voltage at the last device is not less than the manufacturer's rated operating voltage (typically 16V for 24V nominal). Use of 20% drop is a rule of thumb, but 'Manufacturer's Minimum' is the specific S524 requirement. 80% is common. 10% is for signal circuits in some jurisdictions, but S524 allows more. Actually, S524 states the wiring shall be sized so voltage is not less than device rating. 20% is the correct design limit.