Panel schedule and load balancing

Set the panel: name, system (120/240 V single-phase, 208Y/120 V or 480Y/277 V three-phase), the number of spaces, the main breaker (or main lugs) and the bus rating. Or load an example: a house on 200 A, a small shop on 208Y/120 V, a 480Y/277 V lighting panel.

Add circuits — name, VA, 1, 2 or 3 poles, breaker, kind, and cont. for loads that run three hours or more. Balance reseats every breaker that isn’t pinned, biggest first, where it keeps the heaviest phase lightest. To place one yourself, drag it to another slot (on a phone: tap it, then tap the slot), or pick a slot from its list; dropping on a breaker of the same size swaps them, and a breaker you place is pinned.

The cards show each leg or phase’s current with a bar against the main, the neutral current, the imbalance (largest phase against the average), the connected load, the feeder load and the spaces used. Underneath, the problems: a 2-pole breaker that doesn’t land on both legs, a 3-pole that misses a phase, two breakers in one slot, more poles than spaces, a breaker under 125 % of its continuous load, a feeder over the main.

The Panel schedule is the usual layout — circuit numbers, descriptions, VA and breaker/poles down both sides with the phase columns in the middle — with phase totals, amps and the neutral at the foot. Print prints it alone; CSV downloads every circuit with its slots, phases and amps.

Each row of two slots sits on one bus stab; the stabs alternate A, B (or A, B, C) down the panel, so a 2-pole breaker always spans two legs and a 3-pole all three. The VA per phase is the usual schedule figure, a multi-pole load split equally among its poles. The amps are phasor sums at unity power factor: a 2-pole load on a 208Y/120 V panel draws VA ÷ 208 on each of its two phases, and only the 120 V (or 277 V) loads put current on the neutral.

The demand load takes non-dwelling receptacles over 10 kVA at 50 % (220.44) and adds 25 % of the largest motor (430.24); the feeder load adds another 25 % of the continuous loads (215.2(A)(1)). For a house use the dwelling load calculation instead — Article 220’s dwelling demand factors are what size the service.

Related: motor branch circuit, wire size and voltage drop, transformers, fault current, shop power planner (a workshop’s circuits and what can run at once), and energy usage.

Any current browser. Dragging works with a mouse; on a touch screen tap a breaker, then tap where it goes. Works offline once loaded.

Everything runs in your browser and the panel is kept in its local storage. Nothing is sent anywhere; Share link puts the panel in the link itself.