E-House interface register: what to agree before approving drawings

Start with cable entries and civil details

Check foundation loads, anchors, module dimensions and weights, transport splits, lifting points, wall and floor openings, drainage, external stairs, platforms, fire-zone boundaries and site access. Record who provides each item and which drawing defines it.

For every cable entry, specify source, destination, quantity, size, minimum bend radius, segregation, glands, sealing and fire-stopping. A cable route must fit the actual opening and maintenance space.

Assign each electrical connection and control signal

Record system voltage, frequency, fault level, earthing arrangement, auxiliary supplies, neutral treatment, metering boundaries, protection zones and CT/VT data. Identify responsibility for time synchronisation, communication protocols and hardwired trips.

For SCADA, use an I/O list showing source, destination, normal state, fail-safe state and test method. Add addresses, gateways and responsibility for cybersecurity and data. A protocol name alone leaves these details unresolved.

Check operation and maintenance needs

Agree access control, emergency escape, lighting, sockets, fire alarms, gas detection where applicable, HVAC modes, filter access, spares storage and maintenance isolation. Identify local alarms and signals sent to the plant system. If a subsystem must remain available with the main bus de-energised, show its power source and autonomy on the drawings and include the agreed FAT check.

Review open items before releasing drawings

Start the register during tender clarification and update it with the general arrangement and single-line diagram. Resolve critical items before releasing the affected work for manufacture, or obtain the responsible parties’ documented acceptance of a defined hold or limitation. A name and due date alone do not resolve an outstanding technical issue.

Record agreed changes and superseded entries against drawing revisions. Continue updating the register through FAT and site handover so the supplier and buyer can see remaining work and changes to the contracted scope.