Battery Energy Storage Switchgear and AC Distribution RFQ Guide

Prepared by: JCON ELECUpdated: 2026-10-16

Short answer

For BESS switchgear, start with PCS AC voltage, current, quantity, fault data and the connection diagram, not MW or MWh alone. Define the LV/MV equipment, transformer and auxiliary interfaces separately from batteries, PCS, DC equipment, BMS/EMS and complete-system acceptance.

GCS low-voltage switchgear for AC distribution review

Start with PCS data and the AC connection diagram

Storage power in MW, energy in MWh and PCS terminal voltage describe different requirements. Distribution equipment is selected from the electrical interfaces and operating conditions, rather than battery capacity alone.

AC collection panels and PCS feeders with project-defined protection and isolation.
LV/MV switchgear, transformer interfaces, metering and auxiliary distribution.
Battery racks, PCS, BMS/EMS, thermal management and fire systems require a separate scope agreement.

Supply scope and interfaces

Supply scope and interfaces
Package item	Information to confirm	Boundary to agree
PCS AC distribution	AC voltage/current, feeder quantity, fault contribution and earthing	Match the specified PCS; do not assume a standard 400V assembly fits
Transformer and MV package	Transformer ratings, connection diagram, MV voltage and protection	Allocate transformer supply, cabling, metering and auxiliary connections
Battery, PCS and DC systems	Supplier data, trip signals and integration interfaces	Confirm separate supply, BMS/EMS, fire protection and system testing

Information to include in the RFQ

Storage and operating basisMW/MWh, PCS quantity, charging/discharging duty, grid-connected or island operation and project SLD.

PCS AC interfaceAC voltage range, rated current, fault contribution, neutral/earthing and cable termination details.

Transformer and MV systemTransformer ratings, impedance, vector group, MV voltage, utility fault level and protection requirements.

Auxiliaries and controlHVAC and control loads, auxiliary source, emergency-stop/trip signals, communication and ownership of EMS interfaces.

Environment and documentsInstallation, IP, temperature, altitude, layout, approved standards, FAT, drawings, destination and delivery terms.

Related distribution equipment

Low Voltage Switchgear

Main distribution, outgoing feeders and auxiliary power configured to the SLD.

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Medium Voltage Switchgear

Incoming, metering, bus section and feeder panels with project-specific protection.

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Prefabricated Substation

Coordinated MV, transformer and LV package boundaries for project review.

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How to compare supplier quotations

AC/DC boundariesList supplied AC equipment and separately identify battery, PCS, DC equipment and system integration responsibilities.

Bidirectional dutyVerify suitability for charging and discharging, thermal duty and the approved protection scheme.

Ratings and voltageDo not substitute a standard 400V panel for a different PCS output voltage without design verification.

Project acceptanceSeparate equipment tests from complete BESS testing, grid approval, installation and commissioning.

Frequently asked questions

Does this guide cover a complete battery storage system?It focuses on AC distribution and switchgear interfaces. Batteries, PCS, BMS/EMS and other BESS systems are separately identified and confirmed in the supply agreement.

Is MW or MWh enough to select the switchgear?No. The RFQ also needs PCS AC voltage, current, quantity, fault data, transformer information, operating duty and the SLD.

Can existing LV switchgear be used with any PCS?No. Voltage, current, insulation, fault level, protection and operating duty must match the specified PCS and project design.

Sources and scope

This JCON ELEC procurement guide organizes equipment and interface questions for project review. JCON product pages describe available equipment families; external manufacturer material is technical background, not evidence of JCON authorization, certification or a complete plant offer. Final ratings, compliance and responsibilities require approved project documents and an agreed supply scope.

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