There is no single cable size to buy for a 7 kW charger. A 7 kW charger sits in the 32 A class, and because EV charging is a continuous load, its circuit is sized at 125% of the charging current — a 40 A circuit. The supply cable for that circuit is building wiring, specified by a licensed electrician under your local code — the only cable supplied with the charger is its own lead.
Key Takeaways
- A 7 kW charger is a 32 A-class continuous load, so it sits on a 40 A circuit.
- The supply cable is building wiring, specified by a licensed electrician for that circuit — not a product you pick from a chart.
- Plug-in portables move the question to the circuit behind the outlet; hardwired units make it part of the install design.
- Arrive with the charger setting, the route and the run length — the inputs the specification is built from.
The Decision Sequence for a 7 kW Install
The right answer arrives at the end of a short sequence, not from a chart. Each step has an owner:
| Step | The question it settles | Who settles it |
|---|---|---|
| 1. Read the rating | The current the charger will run at — nameplate, or a lower setting you choose | You, from the charger’s manual and settings |
| 2. Size the circuit | The circuit is rated at 125% of the charge current — 32 A of charging sits on a 40 A circuit | The code rule, applied by your electrician |
| 3. Choose the form | Plug-in portable or hardwired wallbox? Each makes “the cable” a different thing | You, before the electrician visits |
| 4. Specify the cable | Conductor type and size for that circuit, over your run length, by your installation method | Your licensed electrician, under the local code |
| 5. Permit and inspect | The finished circuit is checked as building work | Your local authority’s process |
Notice what the sequence never produces: a size you can order in advance. Our orientation guide to wire sizes for EV chargers shows typical results of the calculation — background for the conversation, not a shopping list.
Plug-In or Hardwired Changes the Question
Many 7 kW-class chargers are plug-in portables. The EV-ACS3210T (about 7.7 kW, NACS, adjustable in six steps from 10 to 32 A) and the EV-ACS3210E (about 7 kW, Type 2) both end in a plug, so there is no supply cable for you to choose at all. The question becomes whether the circuit behind the outlet is rated and wired for a continuous charging load — an assessment for your electrician, not an assumption.
A hardwired wallbox is the opposite case: the supply cable runs straight into the unit, and its specification is part of the installation design. Either way the charger’s lead is a fixed part of the listed product — the variable is always the circuit.
What to Hand Your Electrician
You cannot specify the cable, but you can make the specification fast by arriving with the inputs it depends on:
- The charger and its setting — the model, and the current it will be configured to draw.
- The route — where the panel is, where the charger will sit, and how far apart they are.
- The environment — indoors or outdoors, and what the run must pass around.
- The panel’s spare capacity — or permission for the electrician to assess it first.
Cable and breaker are chosen together, for the same circuit — see our guide to breaker sizes for EV chargers.
Three Mistakes to Avoid
- Buying cable from a generic chart. A chart cannot know your cable type, run length or local code — what the real specification turns on.
- Running a portable on a general-purpose extension lead. A charger draws full current for hours; that is continuous-load work, not a job for a household extension lead.
- Assuming an existing circuit suits. A spare circuit may look right and still not be rated or wired for hours of continuous draw. Have it assessed first.
Frequently Asked Questions
Can I buy the cable myself and have the electrician fit it?
You can, but only buy what the electrician specifies after assessing the circuit and the run. Buying first risks the wrong type or size, and the saving disappears if it has to go back.
Does the length of the run change the cable?
It can. Voltage drop over a long run can push the specification up a size — one more reason the size is calculated for your install, not looked up.
My 7 kW charger is adjustable. Does that change the cable?
The circuit follows the setting the charger is installed at. Agree the setting with your electrician first: a lower setting can suit an existing circuit; turning it up later means new wiring.
Related Reading
- What Size Wire Do You Need for an EV Charger?
- What Size Breaker Do I Need for an EV Charger?
- How Is an EV Charger Wired? A Plain-English Overview
