A compact DC charger asks a modest question of a building. The site supplies AC power; the conversion to DC happens inside the charger, and the input draw sits in the same class as a 22 kW AC charging point. It does not need the supply conversation of a corridor fast charger — but the exact feed, protection and connection are your electrician’s assessment, not a number a product page can give you.
Key Takeaways
- The building supplies AC; conversion happens inside the charger, so the input draw sits in the 22 kW class.
- The exact input rating is a nameplate figure — get it in writing for your electrician instead of working from an article.
- Corridor DC figures (50–350 kW, DOE-cited U.S. costs) describe a different class and a different supply project.
- Capacity first: one measurement on the existing supply decides whether the project stays simple.
What the Supply Actually Feeds
On a DC charger, the building never sees DC. Your supply feeds the station with AC, and the station’s own electronics convert it — which is why the input side of a 22 kW DC unit looks like the input side of a 22 kW AC point, not like a small substation. The input draw will sit somewhat above the 22 kW delivered to the car, because conversion is not lossless. How far above is a nameplate figure — get the exact input rating from the plate and manual, in writing, before your electrician prices anything. Treat the draw as continuous for the length of a session — a charger at full rate for an hour is not a kettle boiling for three minutes. How DC fast chargers work explains where the conversion happens and why it shapes the supply question.
The Questions Your Electrician Answers
No article can size your feed. What it can do is list the questions the assessment has to close, so nothing surfaces after the concrete is poured:
- How much spare capacity does the existing supply and board have, at the hours the charger will run?
- Where does the feed run, and what protection and isolation does the circuit get?
- Does your network operator need to be notified, or to approve the connection? Their process, the electrician’s confirmation — no rule is stated here either way.
- Is the charger the site’s only unit, or the first? Headroom decided now is cheaper than a second supply conversation later.
- What gets recorded — board, circuit, protection — so the next electrician starts from a document, not a guess?
A Different Conversation From Corridor DC
The word “DC” drags corridor numbers into meetings where they do not belong. Keep the two classes apart:
| Corridor-class DC fast charging | This compact DC unit | |
|---|---|---|
| Output | 50–350 kW (the U.S. DOT’s DC fast band) | 22 kW on the product page |
| Where planning starts | The supply itself — capacity at that scale drives the project | A capacity check on the existing supply |
| Cost context | DOE-cited U.S. figures: about $38,000–$90,000 equipment plus $20,000–$60,000 installation | Those U.S. corridor figures do not describe this unit — price your site from installed quotes |
The compact point sits in the middle row: whether your existing supply can carry one more 22 kW-class load is a measurement, not a construction project.
The EV-RHDC30K-L’s Side of the Conversation
The EV-RHDC30K-L is a floor-standing, single-connector DC charger: 22 kW on the product page, in the class described as 22 kW DC, with an LCD and an IP54 enclosure. One unit takes one feed, sized by your electrician from the nameplate rating. A second unit is not a shared-supply claim — it is the multiplication question (two 22 kW-class loads, your simultaneity pattern) put back to the same assessment. The unit speaks OCPP 1.6J — no bearing on the feed, but it belongs in the same project file. Our breakdown of commercial installation costs shows how the supply side drives larger projects’ totals.
Frequently Asked Questions
Can it run on our existing three-phase supply?
Possibly — and only the capacity assessment answers it for your building. The input class at least makes it a realistic question worth an electrician’s visit. Site selection plays a part: a shorter feed run is a simpler circuit.
How many amps does it draw on the input side?
This article does not state a figure, because the input rating is a nameplate value that belongs in your installer’s hands, not in a blog post. Get the rating-plate data in writing, hand it to your electrician, and let them size the circuit from it.
Do we need the network operator’s permission?
It depends on your supply, your operator and your area’s process — one of the assessment questions above. No general rule is stated here; an installer who gives you one without seeing your supply is guessing.
Related Reading
- How Much Does It Cost to Install a Commercial EV Charging Station?
- Where to Install an EV Charging Station: Site Selection Guide
- How Do DC Fast Chargers Work?
