Template · Solar and storage

Grid-tied PV with DC optimizers single line diagram

An optimizer under each module, two strings to one inverter, backfed at the main panel. Use this for a string inverter with a DC optimizer under each module. The optimizers are drawn between the array and the inverter, because they are part of the rapid shutdown system and they set how the strings are laid out.

A free template with typical ratings, conductor callouts and general notes. Open it, change what differs on your job, fill in the title block and export a PDF.

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Grid-tied PV with DC optimizers single line diagram: an optimizer under each module, two strings to one inverter, backfed at the main panel. — Grid-tied PV with DC optimizers. 11 devices on an 11 × 17 in sheet with a title block and notes column.

What the reviewer checks on this drawing

The reviewer checks the busbar arithmetic, the inverter output at 125%, the string lengths against the inverter manufacturer’s limits, and that the optimizers and the inverter are listed together for rapid shutdown, with the initiator labelled.

What the drawing shows

Every device on the sheet, in the order power reaches it.

Symbol	Label	Rating or detail	Conductors feeding it
Utility source	Utility service	120/240V 1φ 3W
Meter	Utility meter	200A socket	Service conductors, per utility
Circuit breaker	200A 2P	Main breaker
Panel	Main panel	200A bus · 120/240V
Circuit breaker	Branch breakers
To (continues off sheet)	To house loads
Circuit breaker	40A 2P	PV backfeed, opposite end from main
Disconnect switch	AC disconnect	60A non-fused · outdoors, lockable, visible blade	3 #8 Cu + #10 G
Inverter	String inverter	7.6 kW · 240V · 32A, integrated DC disconnect
DC/DC converter	DC optimizers	20, one under each module	PV wire #10 Cu + #10 G, 2 strings of 10
PV array	PV array	20 × 400W = 8.0 kW DC

Notes on the sheet

Busbar check: 200A bus × 120% = 240A ≥ 200A main + 40A PV breaker (NEC 705.12). PV breaker at the opposite end of the bus from the main breaker and labelled.
Inverter output 32A × 125% = 40A.
Rapid shutdown (NEC 690.12; CEC Rule 64-218): the optimizers and this inverter are to be listed together as a rapid shutdown system. Opening the AC disconnect starts it; that disconnect is outdoors, readily accessible and labelled as the rapid shutdown initiator.
String length within the inverter manufacturer’s limits: the fewest and the most optimizers in a string, and the most watts.

Diagram is schematic and not to scale. Field-verify existing equipment ratings. Ratings and conductor sizes shown are typical. Confirm against the adopted code, the equipment listing and a load calculation before installation. Code references are to the 2023 NEC and the 2024 Canadian Electrical Code: see references and editions.