About the Access & Clearance
Access clearance planning defines the minimum safe distances around electrical equipment in a solar plant or BESS — meeting IE Rules, CEIG requirements, and equipment manufacturer specifications for safe operation, maintenance, and emergency access.
How to calculate it
- 1LT switchgear (< 1,000 V): minimum 1 m front clearance (working space); 0.6 m rear and sides where access is needed.
- 2HT switchgear (11 kV): minimum 1.5 m front clearance; 1.2 m rear and sides; 2.5 m clear height.
- 3Transformer yard: 1.8 m minimum from transformer tank to boundary fence; 1 m between transformers.
- 4Battery containers: 1.5 m maintenance clearance on service side (where racks are accessed); 0.6 m on sealed sides.
- 5Inverter: per manufacturer datasheet — typically 0.3–1 m on all sides for airflow and service access.
- 6Verify with CEIG (Chief Electrical Inspector to Government) requirements for the state — they vary.
Worked example
A 1 MWp plant with 11 kV switchgear and 1 MVA transformer: switchgear room dimensions allow 1.8 m front clearance (allows two people to work simultaneously), 1.2 m rear access passage. Transformer yard: 3 m × 4 m bunded area with 1.8 m clearance on all sides from the fence. BESS container: 2 m service-side clearance (allows rack replacement with forklift).
What you can calculate
- Clearance mm
- IEC 62619
- Service access
- Emergency egress
Standards & references
Frequently asked questions
What clearances are required around a rooftop solar inverter?
String inverters (5–50 kW) typically require 300–500 mm clearance on the sides and top for airflow, and 600 mm front clearance for service access (display, cabling, fuse replacement). Central inverters (250 kW+) require 1–1.5 m on all sides. Always check the manufacturer's installation manual — some string inverters can be installed with only 100 mm side clearance if the top is open, but the warranty may be voided if clearance requirements are not met.
What is a bunded area for a transformer?
A bunded area (oil containment pit) is a concrete or brick enclosure around an oil-filled transformer designed to contain oil in case of a leak or fire — preventing oil from running into drainage, adjacent equipment, or soil. IE Rules and IS 2026 require that oil-filled transformers above 50 kVA have a bund with capacity to hold the full oil volume plus 10% buffer. The bunded area is filled with clean gravel that allows oil to drain to a sump without igniting.
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