Sandbox

Build your own scenario.

Mix breakers, fuses, LVPCBs, and damage curves on a single TCC. The plot detects coordination overlaps automatically — flagged in red where two device curves cross.

Educational tool only. Generic representative curves, not manufacturer data. Don't use this for real coordination studies, breaker selection, or AHJ submissions — use a licensed production tool and a qualified protection engineer for any real-world decision.

Scenario preset

The current sandbox seed: 1600 A LVPCB main, 400 A TM MCCB feeder, 100 A RK5 fuse branch. Clean selective coordination across the LV range.

Main · 1600 A LVPCB Sensor rating A

Long-time (L)

L pickup × (1440 A) L delay (@ 6× pickup) s

Short-time (S)

S pickup × (9600 A) S delay s S I²t in (sloped band)

Instantaneous (I)

I pickup × (OFF)

Feeder · 400 A TM MCCB Rating (continuous) A Instantaneous trip × (4000 A) Long-time band shift ×

Branch · 100 A RK5 fuse Rating A

Class RK5 · general-purpose dual-element time-delay

3 devices on the plot.

Things you can do here

Pick a device kind from the dropdown before clicking add — TM MCCB, Class L/J/RK5/T fuse, LVPCB-LSI, or a cable / transformer damage curve overlay.
Stack damage curves with protection devices. Add a cable or a transformer alongside your breakers and fuses — the dashed amber curves are the equipment damage envelopes. Your protective devices must clear below them.
Watch for the red ✕ markers. They flag where two device curves cross — i.e. coordination is lost at that fault current. Adjust settings until they disappear.
Scenario sharing via URL. Every device tweak updates the address bar so you can copy and DM a coordination puzzle. Hit Copy share link above to put the current URL on the clipboard.

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