Tools
POWER CALCULATOR
Build your gear list and calculate total power draw. See how many 120V/20A circuits you need and whether you're within safe load limits.
Gear List
| ITEM | AMPS | QTY | TOTAL | |
|---|---|---|---|---|
| — | ||||
Total Draw
0.0A
0W @ 120V
Circuits Needed
0
120V / 20A @ 80%
Load / Circuit
—
No gear added
Gear Items
0
0 line items
Add gear above to calculate power requirements.
The 80% Rule
Why We Derate to 80%
The National Electrical Code (NEC) requires that continuous loads — loads expected to run for 3 hours or more — do not exceed 80% of the circuit breaker's rated capacity. AV gear on a show floor qualifies as a continuous load.
A standard 120V/20A circuit is rated for 20 amps, but the safe continuous limit is 16 amps. Exceeding this causes heat buildup in the wiring and breaker, leading to nuisance trips during your show — usually at the worst possible moment.
16A
Safe continuous load
80% of 20A circuit
1,920W
Max watts per circuit
16A × 120V
20A
Breaker trips here
Don't find out live
Real-World Notes
- ▸Inrush current on power-up can spike 2–5x the rated draw. Power on gear in stages, not all at once.
- ▸Amplifiers draw rated current only at full output. Typical corporate speech reinforcement uses 30–50% of rated power. Music playback uses more.
- ▸LED walls and moving lights vary significantly with content brightness. A full white screen or full intensity wash draws maximum rated power.
- ▸Always confirm available power with the venue before the show. Many hotel ballrooms have limited circuit counts in the floor boxes.
- ▸For large shows, you'll need 208V/3-phase distro from a tie-in or generator. This calculator covers 120V/20A single-phase only.
Power Planning Is a Skill
List your technical production skills on Truss. Producers need techs who can plan power, run distro, and keep the show running.