Quick answer
Specify the compact substation supply boundary with named interfaces and deliverables. “Complete package” is too ambiguous for a purchase order: a factory assembly can be complete while its external cable terminations, foundation, utility approvals and remote communications still belong to separate contracts.
Separate the equipment package from the installation
IEC distinguishes prefabricated substation equipment from the wider design and erection of power installations. That distinction helps buyers structure a contract, but a standards reference does not assign commercial responsibilities between contractors. See the published scopes of IEC 62271-202 and IEC 61936-1.
Mark the physical boundary on the general arrangement: an MV terminal, LV bus connection, earth bar, auxiliary terminal strip or communications port. For each one, record who provides the mating component and who verifies the completed interface. Keep design responsibility separate from delivery responsibility; an item supplied by one party may require dimensions or calculations from another.
Use an interface schedule with four owners
The following is a procurement worksheet, not a default allocation of Jinxing's scope. Replace every open entry with the responsible company and a drawing or document reference.
| Interface | Design information needed | Supply and installation decision | Acceptance evidence |
|---|---|---|---|
| Foundation to enclosure | Approved loads, fixing points and openings | Who supplies anchors, grout and civil work? | Survey and accepted foundation record |
| External MV cable | Cable construction and terminal interface | Who supplies cable, accessories and termination labour? | Cable and connection test responsibility |
| External LV connection | Busduct or cable connection drawing | Who provides flexible links and supports? | Agreed connection inspection record |
| Site earth grid | Earth study and connection locations | Who supplies external conductors and bonds? | Site earthing acceptance record |
| SCADA handover | Point list, protocol and network boundary | Who supplies gateway, network service and configuration? | Point-to-point test and command acceptance |
Include unloading, lifting, storage protection and site attendance as separate cost lines. An export delivery term alone does not explain who will terminate a cable or attend an energisation meeting.
Example: two quotations that appear identical
Consider a hypothetical warehouse project receiving two package prices. Both include MV equipment, transformer and LV distribution inside an enclosure. One price includes internal wiring to a terminal strip; the other also includes a gateway. Neither includes the control-centre integration engineer.
Comparing only the package totals would hide both a hardware difference and a service gap. Ask each bidder to complete the same schedule, price missing interfaces separately and identify assumptions. The owner can then compare the cost of the same accepted scope, including integration attendance.
For civil work, request the equipment information release date. A contractor cannot finalise the foundation from a preliminary catalogue outline when cable openings and shipping splits are still changing. Put drawing revision and acceptance status beside the promised delivery date.
Make changes visible after the order
Attach the agreed schedule to the purchase order and use it during design review. When a cable type, communications protocol or utility requirement changes, record which boundary moved, who owns the revised drawing and whether price or programme changes. This gives the project team a traceable decision instead of an email chain of assumptions.
Information to send with an enquiry
For a YB prefabricated substation or another compact substation configuration, send the preliminary single-line diagram, site location, equipment ownership split and proposed cable and SCADA interfaces. Identify any civil or commissioning work you expect in the quotation.
Use the project enquiry page to request an itemised offer and interface schedule. Final equipment ratings, included services and applicable supporting documents need confirmation for the proposed project.