Protection

Protection data and scope

Protective-device information belongs to the distro definition so workspace and project distro models can supply their incomer and output protection automatically. When a project distro has no configured protection, the Protection tab provides an editor for entering it.

The tab is a forecasting and system-design aid. Measured inspection and test results belong in System Sign-Off, particularly G2, rather than Engineering.

Distro and circuit views

Protection uses collapsible tables grouped by distro, with the same distro filter, unused-output control and Expand all or Collapse all actions as Load & Demand and Cable Design.

The circuit information icon shows connected equipment and notes. Incomer protection is displayed above the circuit rows, while output devices can be reviewed or edited against each circuit.

Overload coordination

The indicative load-and-cable check compares design current, protective-device rated current and adjusted cable capacity using the relationship Ib ≤ In ≤ Iz.

Incomplete means required device or cable data is missing. Conflict identifies a rating relationship that does not satisfy the screen. Indicative means this limited relationship passes but other device characteristics and fault protection still require competent assessment.

Fault protection and device capability

Prospective fault current can be entered at the manual source, distro incomer or individual circuit. A downstream value inherits from upstream unless a closer override is entered.

The device-capability screen compares entered prospective fault current with protective-device breaking capacity. Estimated design Zs and maximum permitted Zs remain user-entered values, and the source of the maximum value should be recorded.

Residual-current selectivity

Where upstream and downstream residual-current devices form a protection path, the planner screens the pair and suggests an upstream residual-current setting and adjustable delay intended to support downstream-first operation.

Suggestions consider declared available settings and generic grading relationships. Fixed devices remain visible, while variable RCD settings and time delay can be accepted from the suggestion or manually overridden.

An MCB with associated RCD protection participates in MCB overload and breaking-capacity checks while its separate residual-current function participates in the RCD selectivity path. It is not treated as an RCBO.

Designer overrides

Use the override controls when the selected setting intentionally differs from the planner suggestion. Record the reason so the design decision remains visible and traceable.

A designer override does not turn an otherwise conflicting arrangement into verified compliance; manufacturer selectivity tables, device types, operating curves and installation conditions still govern the final decision.