Event power planning
Voltage drop: information needed to review a cable run
Distance matters together with current, cable characteristics and the source supply. To compare alternatives, the provider needs the complete route and the most demanding operating conditions.
Record the route and its loads
- Source and destinations, each segment’s length with units, branches and expected current in each segment.
- System, voltage and frequency; exact cable, material, conductor size, documented resistance and reactance with reference temperature.
- Intermediate connections, installation conditions and equipment input range. Keep steady operation separate from startup.
A simplified example with complete loop resistance
Assume a two-wire single-phase circuit, 230 V at the source, steady 10 A, power factor 1 and 0.4 Ω total outgoing-and-return resistance at operating temperature. Neglect reactance and all other drops: ΔV = 10 A × 0.4 Ω = 4 V; 4 V / 230 V × 100 ≈ 1.74%.
The calculation uses an assumed resistance. To select a cable, the professional needs its actual data and the applicable acceptance criteria. Do not double the length again if resistance already includes both conductors. Three-phase or nonlinear loads require the appropriate calculation model.
Compare alternatives on the same basis
Ask about a closer handoff point, a different route or suitable cable, keeping the compared loads consistent. Include upstream segments and equipment input limits. A qualified professional verifies actual conditions; do not take measurements inside energized panels.
Planning questions
Is correct no-load voltage enough?
It does not necessarily describe behavior under load or during startup. Share the conditions and request appropriate verification.
Does a low drop percentage prove cable ampacity?
No. Thermal capacity, protection and other checks are still required.
Does every segment carry total current?
Not when there are branches. Document which loads each segment serves so its own load is used.
Sources and scope
Technical reference documentation. Venue staff and a qualified professional review its application to the actual installation.
Before finalizing the supply, confirm venue and local authority requirements in the United States, or utility and local requirements for an event in Argentina. Confirm the actual site’s electrical configuration regardless of this guide’s language.