Outdoor Community Stage: Shared Power and Cable Route
You are the lead technician for a one-night barangay anniversary program in an open lot from 18:00 to 22:00. The package is 12 × 30 W LED PAR fixtures, two 500 W powered speakers, an 8-channel mixer, and two wireless microphones. The only nearby power is two 16 A outlets, A and B. The caretaker says both are on one 20 A breaker and that A also feeds a refrigerator and a water dispenser. Stage left is 25 m from the outlets, but your longest extension cords are 20 m. A 5 kVA generator is available, but it has fuel for only about three hours. The main audience walkway passes between the stage and the mixing position. The client wants no visible cables and a prompt 18:00 start. Rain is forecast after 21:00.
1. What power plan would you propose before load-in, and what checks must happen before the 18:00 start?
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Start with a load estimate, not the outlet label. Lighting: 12 × 30 W = 360 W. Treat the two powered speakers as 1,000 W program total, plus 100 W for mixer and receivers, giving about 1.46 kW, or roughly 6.4 A at 230 V. That is within a healthy 16 A circuit, but the 20 A breaker is shared with a refrigerator, whose compressor inrush can trip it, and the caretaker’s statement is not proof that A and B are separate. Before load-in, verify at the panel: switch one breaker and confirm which outlets die; use a socket tester and RCD test; measure voltage. Plan A for lighting and B for audio only if they are truly separate. Keep the refrigerator off the audio circuit. If they are not separate, use the 5 kVA generator for audio or lighting, place it outdoors, ground it, and use an RCD. The generator can carry 1.46 kW easily, but three hours of fuel cannot cover 18:00–22:00 plus sound check; arrange refueling or a second can before the event. Run a 30-minute load test and check plug and connector temperature.
2. How would you route power to the stage given the 25 m distance and the public walkway?
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The 20 m cords do not reach 25 m, and daisy-chaining two 20 m light-duty cords adds resistance and loose connections; do not do it. Use one 25 m heavy-duty three-core extension of adequate gauge, or relocate the distro closer. Route the cable away from the audience walkway: overhead on a catenary or truss if possible; otherwise use a rated cable ramp or mat across the walkway and keep the connection point out of standing water. Keep audio and power runs separated and cross at 90° if they must cross. Use IP-rated connectors or a covered distro; support cables so they do not pull on plugs. Test the RCD before energizing and keep the generator and distro covered. If the route cannot be made safe, change the layout or delay the start rather than tape a cable to the floor and hope.
3. How would you handle the client’s request for no visible cables and a prompt start?
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Tell the client early and specifically: ‘We can start at 18:00 only if we use a visible cable ramp across the walkway or an overhead route; hiding all cables is not safe with the available lengths.’ Offer options: move the mixing position, accept a mat, or authorize a generator placed away from the audience. Confirm who will refuel the generator and at what time; set a hard decision point for rain at 21:00 and a covered shutdown plan. Put the agreed power plan and cable route in the event sheet, assign one person to check the RCD and connectors at 17:30 and again at 20:30, and tell the client that the schedule may slip if the electrical check fails. This is a communication and quality-record issue, not just a technical one.