What is voltage drop?
Simple definition
Voltage drop is the reduction in voltage along a cable caused by cable resistance and current draw.
Why it matters in wiring diagrams
It matters for locks, maglocks, sirens, strobes, cameras and remote DC loads.
When reading a wiring diagram, this term usually affects cable choice, power path, signal path, device selection or commissioning notes.
Common mistakes
- Assuming the term means the same thing across all brands.
- Ignoring the actual terminal names in the manufacturer manual.
- Not documenting how the term applies to the final installed system.