EV charger wallbox surge protection for Germany starts with a rung that does not fit. A 230 V supply with 10 percent tolerance reaches 253 V rms, and Walsin’s 250 Vac varistor rung stops 3 V short. The next rung, 275 Vac, has 17 rows, and we counted zero varistors among the 1,125 part numbers on our shelf.
Venatech Limited, an authorised Walsin distributor in Hong Kong, wrote this from the Walsin Technology (Walsin) varistor export (379 rows, 379 distinct part numbers) and our stock list as at 23 September 2026. It is for a design or sourcing engineer at a German wallbox or charge-point maker who must pick a mains varistor and wants the differences stated before a quote. Every part number is real, every count is ours, and each market figure names its source and the day we fetched it, 23 October 2026.
How fast is Germany adding public charge points, and what does that leave out?
Quickly, and the count is public points only. The Bundesnetzagentur figure relayed by electrive on 7 September 2026 is 212,064 public charge points as of 1 August 2026: 156,399 normal points up to 22 kW and 55,665 fast points above 22 kW. Six months earlier, ecomento reported 196,353 as of 1 February 2026, of which 49,904 were fast.
| Point | Figure | Source date | Match / mismatch |
|---|---|---|---|
| Public points, 1 February 2026 | 196,353 (146,449 normal, 49,904 fast) | ecomento, 11 March 2026 | Match for market context only |
| Public points, 1 August 2026 | 212,064 (156,399 normal, 55,665 fast) | electrive, 7 September 2026 | Match for context; up 15,711, or 8.0 percent |
| Fast points, same two dates | 49,904 to 55,665 | as above | up 5,761, or 11.5 percent |
| Private wallboxes | not in either figure | as above | Mismatch: the register counts public points |
Both pages count public points, so a home or fleet wallbox does not appear in them. We draw one conclusion, and it is ours: every point on that list has a mains input that needs surge protection, and every maker behind it chooses a varistor. We have no relationship with either publisher and no knowledge of what any German charger company buys.
Which varistor rung does a 230 V wallbox supply need?
The 275 Vac rung, by a small margin. On our working assumption of a 230 V phase-to-neutral supply with a 10 percent upper tolerance, the varistor sees 253 V rms; the 250 Vac rung is 3 V, 1.2 percent, short, and the 275 Vac rung leaves 22 V, 8.7 percent. Confirm the supply tolerance and your own margin rule.
We parsed all 379 rows of the varistor export. The working-voltage column holds 35 rungs, and 13 of them carry 17 rows each, including the 250, 275 and 300 Vac rungs. The 250 Vac rung carries a varistor voltage of 390 Vdc in every row; the 275 Vac rung carries 430 Vdc in every row. So moving up one rung to clear 253 V also raises the voltage at which the part starts to conduct by 40 V. In our view that is the cost of the missing rung, and the export has no clamping-voltage or energy column to measure it further. Every one of the 379 rows states its working voltage in Vac and none in Vdc.
Of the 379 rows, 184 are rated 275 Vac or higher and 195 are lower, so about half the table is irrelevant to a 230 V board before any other field is read. We have not seen this counted anywhere. Our post on crossing Bourns and Littelfuse varistor families to Walsin covers the family names, and our post on EV charger surge protection for the United Kingdom takes the 440 V line-to-line case.
Which Walsin varistor rows cross a 253 V wallbox brief, and what differs?
One row matches on every field you can state. Take a brief of at least 253 Vac, a 10 mm disc and a peak current of at least 2,500 A, a placeholder for your own figure: SR431K10D matches on all three, and five neighbours differ in voltage, current or size. The last column is for your incumbent.
| Walsin part | Rung, disc, series, peak current | Varistor voltage | Match / mismatch with the brief | Your incumbent |
|---|---|---|---|---|
SR431K10D |
275 Vac, 10 mm, Standard D, 2,500 A | 430 Vdc | Match on voltage, size and current | |
SR391K10D |
250 Vac, 10 mm, Standard D, 2,500 A | 390 Vdc | Mismatch: 3 V short of 253 V | |
SR431K07D |
275 Vac, 7 mm, Standard D, 1,200 A | 430 Vdc | Mismatch: smaller disc, half the current | |
SR431K14D |
275 Vac, 14 mm, Standard D, 4,500 A | 430 Vdc | Match on voltage and current; mismatch on size, larger disc | |
SR431K10E |
275 Vac, 10 mm, Super High Energy, 4,000 A | 430 Vdc | Match on voltage and size; mismatch on series and current, higher | |
SR471K10D |
300 Vac, 10 mm, Standard D, 2,500 A | 470 Vdc | Mismatch: one rung higher, varistor voltage 40 V up |
All six are listed with a plus or minus 10 percent varistor voltage tolerance. The peak current figure has no waveform stated in the export, and we hold no varistor datasheet, so we cannot say which pulse it refers to. Confirm against both datasheets and qualify in your own circuit.
Is any Walsin varistor on the Hong Kong shelf for a German wallbox maker?
No. Our stock list as at 23 September 2026 holds 1,125 part numbers, and none is a varistor: 732 are MLCC, 132 specialty MLCC, 254 chip resistors, 3 safety capacitors, 2 inductors, 1 resistor array and 1 other. Zero of 379 varistor rows are stocked.
That makes a varistor a quote-and-order item for us, and we state no lead time or availability here. The ready-stock list is a dated snapshot, never live-synced. The varistor range lists the families, and our post on Walsin passive components in Hong Kong stock explains what the shelf does cover.
What do Walsin’s documents say about chargers and varistors?
Nothing on either. We converted all 28 Walsin datasheets we hold, 451 pages, to text and searched them: charging, charger and wallbox each appear in 0 of 28 files, and none of the 28 is a varistor sheet. The inductor, varistor, disc, RF, antenna and thin film lines have no datasheet in our set.
What can a Hong Kong distributor not tell a German charger maker?
Anything about German or European charging, grid or product rules. We hold no office, entity or stock in Germany; our locations are Hong Kong, Shenzhen, Singapore and Jiangmen, with Chengdu in preparation. We state no duty, customs position, transit time or carrier, and we give no legal, customs or compliance advice; confirm with your compliance team. We make no claim that any Walsin part is approved for an EV charger, and we hold neither ISO 9001 nor IATF 16949.
How Venatech helps
Paste your incumbent varistor into the free cross-reference tool, which decodes 18 manufacturers’ part numbers across 800,000+ crossable parts and lists Walsin candidates with each field marked match or mismatch. Upload a wallbox bill of materials to the BOM checker, up to 500 part numbers or an Excel or CSV file, and every line is checked. The Hong Kong ready-stock list is a snapshot dated 23 September 2026.
Worked example from our own export: the 275 Vac filter returned 17 rows and 17 distinct part numbers, from SR431K05D at 400 A to SR431K34RD at 80,000 A, and our shelf covers none of them. Walsin is the only line we are authorised for; Stackpole and Viking are lines we supply. We serve from Hong Kong in small lots, and a quote is requested through the site. We hold lot and date-code traceability, a certificate of conformity per shipment on request and original sealed Walsin packaging; the 28 datasheets, 451 pages, are sent on request. UL file E182369 is in UL’s public database.
The short version
For a German wallbox, the 250 Vac varistor rung is 3 V short of a 253 V supply, the 275 Vac rung has 17 rows, all with a 430 Vdc varistor voltage, and none of the 379 varistor rows is on our shelf. The voltage cross is simple; the pulse rating is the half no document we hold explains.
Send us the varistor from one wallbox mains input and we will return the Walsin candidates with every difference stated. If your supply tolerance were 6 percent, not 10, would the 250 Vac rung come back into the table?
Sources
Fetched 23 October 2026. The market statements come from these pages; the part data comes from our own Walsin export and stock list.
- electrive, “Deutschland ueberschreitet Marke von 212.000 oeffentlichen Ladepunkten”, 7 September 2026, citing Bundesnetzagentur data of 1 August 2026: https://www.electrive.net/2026/09/07/deutschland-ueberschreitet-marke-von-212-000-oeffentlichen-ladepunkten/
- ecomento, “Bundesnetzagentur: Jetzt 196.353 oeffentliche Ladepunkte in Deutschland”, 11 March 2026, data of 1 February 2026: https://ecomento.de/2026/03/11/bundesnetzagentur-jetzt-196353-oeffentliche-ladepunkte-in-deutschland/
Frequently asked questions
How many public charge points does Germany have?
Electrive reported on 7 September 2026, citing Bundesnetzagentur data of 1 August 2026, 212,064 public points: 156,399 normal and 55,665 fast. Ecomento reported 196,353 as of 1 February 2026. Both count public points, not private wallboxes.
Which Walsin varistor rung suits a 230 V wallbox supply?
On our assumption of 230 V with a 10 percent upper tolerance, the supply reaches 253 V rms. The 250 Vac rung is 3 V short; the 275 Vac rung leaves 22 V, 8.7 percent. Confirm the tolerance and your own margin rule.
How many Walsin varistor rows are rated 275 Vac?
17 rows, all with a 430 Vdc varistor voltage, from 400 A at a 5 mm disc to 80,000 A at a 34 mm square. The whole export has 379 rows, 184 of them at 275 Vac or higher. The export has no clamping-voltage or energy column.
Does Venatech hold Walsin varistors in Hong Kong stock?
No. Our stock list as at 23 September 2026 holds 1,125 part numbers and none is a varistor. A varistor is a quote-and-order item, and we state no lead time. The ready-stock list is a dated snapshot, never live-synced.
Do Walsin documents cover EV chargers?
No. Charging, charger and wallbox appear in 0 of the 28 datasheets we hold, 451 pages, and none of the 28 is a varistor sheet. The varistor line has no datasheet in our set. Ask Walsin for surge ratings in writing.
Do you hold stock in Germany or give compliance advice?
No. We hold no office, entity or stock in Germany; our locations are Hong Kong, Shenzhen, Singapore and Jiangmen. We give no legal, customs or compliance advice. Confirm with your compliance team. Qualification stays with you.