Template · Generators

Generator docking station with manual transfer single line diagram

A connection cabinet and a manual transfer switch, ready for a rented generator. Use this for a building that will rent a generator when it needs one: a docking station on the outside wall for the cables, and a manual transfer switch between the utility and the main distribution panel.

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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Generator docking station with manual transfer single line diagram: A connection cabinet and a manual transfer switch, ready for a rented generator. — Generator docking station with manual transfer. 10 devices on an 11 × 17 in sheet with a title block and notes column.

What the reviewer checks on this drawing

The reviewer checks that transfer is by a listed switch and not by the docking station, the switch as the service disconnect, how the generator neutral is arranged for a three-pole switch, and the sign at the service equipment.

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	120/208V 3φ 4W
Current transformer	CT cabinet	Utility metering
Transfer switch	Manual transfer switch	400A · 3-pole · fused 400A, service rated	2 sets of 4 #3/0 Cu
Device	Generator docking station (GDS)	400A breaker · cam-type, connectors · NEMA 3R	2 sets of 4 #3/0 Cu, + #3 G
Generator	Portable generator	100 kW / 125 kVA, 120/208V	Portable cable sets
Ground	Grounding electrode system	GEC moved to the switch
Circuit breaker	400A 3P	Main	2 sets of 4 #3/0 Cu, + #3 G
Panel	Main distribution panel MDP	400A · 120/208V 3φ 4W
Circuit breaker	Branch breakers
To (continues off sheet)	To building loads

Notes on the sheet

The docking station is a connection point only: cam-type connectors behind a lockable door, for a generator brought to site. Transfer is by the manual transfer switch.
Manual transfer switch is the service disconnect. The grounding electrode conductor and the main bonding jumper move to it, and the neutral and equipment grounds are separated at the MDP.
Three-pole switch: the neutral is not switched, so the generator is not a separately derived system and its neutral is left unbonded at the generator. Confirm on the generator before connecting.
Generator 125 kVA at 208V = 347A, within the 400A switch and docking station. Check phase rotation before transferring.
Optional standby system (NEC Article 702). Sign at the service equipment giving the type and location of the standby source connection, and a sign at the docking station that it is for a generator with a floating neutral (NEC 702.7).

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.