EV charger single line diagrams
An EV charger single line diagram shows the path from the utility service to the charger: the meter, the main breaker and panel, the new breaker, the conductors and the charger (EVSE) with its amp rating. Many permit offices ask for one with a Level 2 charger application, because the charger is a large continuous load and the reviewer wants to see that the service can carry it.
The drawings below cover the common cases: a dedicated circuit from the main panel, an energy management system (EVEMS) where the service is near its limit, a charger fed from a subpanel or from a condo unit meter, two chargers sharing power, a commercial bank of chargers and a DC fast charging site. Open the closest one, change the ratings to match the job and export a PDF.
7 EV charger single line diagram templates
Level 2 charger from main panel
Dedicated 60A circuit to a hardwired 48A charger.
EVView drawing
Level 2 charger with load management
Energy management system sheds the charger when the service is near its limit.
EVView drawing
Charger from subpanel with load management
Garage subpanel feeds the charger through an energy management system.
EVView drawing
Condo charger from meter with load miser
Load management device between the unit meter and unit panel feeds the charger.
EVView drawing
Two chargers with power sharing
A 100A EV load centre feeds two chargers that share a group current limit.
EVView drawing
Commercial Level 2 charger bank
Six 32A chargers from a dedicated 208V EV panel.
EVView drawing
DC fast charging site
Dedicated 480V service with two 120 kW chargers and a site-loads transformer.
EVView drawingWhat the reviewer looks for
- The service size and main breaker rating, and whether a load calculation supports the added charger.
- The charger rating and a branch circuit sized at 125% of that continuous load. A 48A charger needs a 60A circuit.
- The conductor size, type and raceway on the branch circuit.
- Any load management: where the current is measured, what the setpoint is and what it switches off.
- Whether the charger is hardwired or cord-connected, and a disconnect where the adopted code calls for one.
The ratings on the templates are typical values, not a design for your job. Confirm what your authority having jurisdiction and your utility expect before you submit.
Questions about EV charger drawings
Do I need a single line diagram for an EV charger permit?
Often, yes. Many building departments and utilities ask for a single line diagram with a Level 2 charger permit, and nearly all do for commercial chargers and DC fast charging. Requirements differ by jurisdiction, so check with your authority having jurisdiction before you apply.
What size breaker does a 48A EV charger need on the drawing?
60A. EV charging is a continuous load, so the branch circuit and its breaker are sized at 125% of the charger’s rated current: 48A × 125% = 60A. By the same arithmetic a 40A charger needs a 50A circuit and a 32A charger needs a 40A circuit.
How is an energy management system shown on a single line diagram?
As a device in the charger circuit, with a dashed line to the current transformers on the service or feeder conductors it measures. Note the setpoint beside it, commonly 80% of the main breaker rating, and state that it interrupts the charger when that current is exceeded.
Other single line diagram templates
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