This simulator puts an off-load disconnector in series with a full three-pole circuit breaker — source → disconnector → breaker → load — so you can see how visible isolation and rated interruption are two distinct jobs. Operate the isolation workbench, prove an absence-of-voltage detector, then step into the breaker's own operator station to charge, close, trip and diagnose it.
• An Isolation workbench: open/close the disconnector, apply or remove an isolation lock, apply or remove a load earth, a mechanical sequence interlock toggle, and an alternate load-side source toggle for backfeed demonstrations, with a live isolation status readout and zone stats. • A Virtual absence-of-voltage test: prove the detector before/after against known references, then test the load terminals, with a detector status readout. • A real-time 3D cutaway of the disconnector plus circuit breaker assembly — copper conductors, silver contact tips, magenta arc zones, cyan sensors and violet trip electronics — with toggleable enclosure, auto-rotate, expand and selectable components. • The full breaker Operator station: charge spring, close breaker, open breaker, shunt trip test, reset trip latch, a trip-free hold checkbox, time controls (1 ms, 20 ms, 1 s, 60 s thermal study) at 20x slow motion to 10x fast-forward, source isolate/restore, and a fault fixture selector (healthy load, balanced three-phase bolted short, welded main contacts). • A Capabilities & protection tab with a function comparison table (disconnector vs. switch-disconnector vs. circuit breaker across off-load isolation, normal load switching, short-circuit interruption and automatic overcurrent protection), plus the same current interruption recorder, time-current characteristic chart, adjustable L/S/I protection settings and trip injection fixture as the breaker-only model. • A Test & diagnose tab with a Verification bench (32 automated checks), a failed-opening diagnostic exercise, and a timestamped event log with session export. • A Learn & assess tab covering interruption versus isolation, guided lessons, a knowledge-check quiz and a written model-scope statement with references.
A circuit breaker is rated to interrupt current under normal and fault conditions, but its contacts are enclosed — you can't visually confirm they're open. A disconnector (isolator) does the opposite: it's built to create a visible, verifiable air gap, but in this model it's an off-load device, not rated to make or break load current. The correct sequence is to open the breaker first to remove load current, confirm clearing, and only then open the disconnector to establish the isolating gap for safe access — which is exactly the sequence the workbench walks you through.
The mechanical interlock normally enforces that order, blocking the disconnector from being operated while the breaker is carrying current. Disabling the interlock and forcing the disconnector open is a deliberate fault demonstration in the model: an arc may persist at the disconnector's unrated contacts until the breaker actually interrupts, which is why interlocks exist in real switchgear.
The function table scores disconnector, switch-disconnector and circuit breaker against four criteria — off-load isolation, normal load switching, short-circuit interruption, and automatic overcurrent protection — showing that only the breaker (with a suitable trip unit) handles automatic protection, while the plain disconnector handles none of the switching duties, only isolation. Many real breakers are also rated for isolation, so the distinction is about tested capability, not a rule that every breaker needs a separate isolator.
The absence-of-voltage sequence models best practice: prove the detector against known live and dead references before and after testing the actual load terminals, because a detector that reads 'dead' without being proven first or after could itself be faulty. The alternate load-side source toggle demonstrates why a single open device isn't sufficient proof of a dead work area — backfeed from another source could still be present. This is an idealized binary voltage-presence model; it excludes induced voltage, stored charge, physical tester faults, neutral/earth measurements and jurisdiction-specific procedures, and the breaker model itself carries the same scope limits as the standalone breaker simulator (no ground-fault protection, no arc-flash energy calculation, teaching-curve time-current data only).
A disconnector (isolator) in this model is an off-load device: it establishes a visible, verifiable isolating gap but is not designed to interrupt load or fault current. The circuit breaker is rated to interrupt current, including overcurrent and short-circuit conditions, but its contacts are enclosed and not visibly verifiable the way a disconnector's open gap is. The comparison table in the simulator lays out these rated functions side by side.
The interlock enforces correct operating order — normally preventing the disconnector from being opened or closed while the breaker is carrying current, since the disconnector is not rated to interrupt load. Disabling the interlock checkbox lets you demonstrate the fault case, where an arc may persist at the disconnector until the rated breaker interrupts.
The workbench includes a virtual voltage detector that you first prove (test it against a known live and known dead reference before and after) and then use to test the load terminals. This models the standard safety sequence of proving a detector works before trusting its "dead" reading, but it is an idealized binary presence/absence model — it excludes induced voltage, stored charge, and physical tester faults.
It demonstrates why opening a single device is not sufficient proof that a downstream work area is dead — an alternate source (such as backfeed) could still energize the load side. This is voltage-presence modeling only, not a reverse power-flow solver, and it reinforces why the workbench's proving-and-testing sequence matters.