Ship electronics for Greece meet a gap on the varistor ladder. We parsed all 379 Walsin varistor rows: the ladder goes 420 Vac, then 460 Vac, and 440 Vac is not a rung. Only 82 rows reach 440 Vac or more, all of them at 460 Vac or above, and none is on our Hong Kong shelf.
Venatech Limited, an authorised Walsin distributor in Hong Kong, holds the Walsin Technology (Walsin) varistor export of 379 rows, 379 of them distinct part numbers. This post is for a design engineer or buyer at a Greek maker of marine power, shore-connection or onboard electronics who has to pick a surge part for a 440 Vac network. Every part number below is real and every count is ours. We hold no varistor datasheet, so every rating is the export’s, not a datasheet’s.
What do Greek shipping and shore power have to do with a component order?
They set the volume and the direction. ELNAVI, reporting on the 2026 survey of the Greek shipping chamber, counts 4,388 Greek-controlled vessels of 360,564,729 deadweight tonnes, 14.2% of the world fleet by deadweight. We read it on 22 October 2026. The page does not show a publication date, so we call it the 2026 survey and nothing more.
The direction is shore power. To Vima (14 June 2025) reports that the EU requires container and passenger ships of 5,000 gross tonnes or more to connect to shore power by 2030, and that Greece’s Igoumenitsa project is due in December 2026 and Rafina’s by the end of 2028. Naftemporiki (30 January 2025) says the grid operator HEDNO had finished studies for seven ports, among them Piraeus and Thessaloniki. Neither article gives a voltage, and we state none.
Our view, labelled as ours: every shore connection adds converters, switchgear and surge protection on the ship side. The sources do not say that.
Where does the Walsin varistor ladder step from 420 Vac to 460 Vac?
Between two rungs, with nothing in the middle. We counted the Max Working Volt. column across all 379 rows: 17 rows are at 420 Vac, 13 are at 460 Vac, and no row sits between them. The next rungs run 485, 510, 550, 575, 625, 680 and 750 Vac.
The jump is 40 V, 9.5% of the lower rung. The sizes that reach it are 10 mm and above in the D series, 18 mm in the E series, 10 mm to 20 mm in the V series, and the Industrial parts. The 5 mm and 7 mm discs stop at 420 Vac. We have not seen this counted anywhere: of the 82 rows at 440 Vac or more, none is at 440 Vac itself, 13 sit at the 460 rung, and 69 are higher.
The arithmetic below is ours, not a rule. A network nominally at 440 Vac is above the 420 rung before any tolerance. At 460 Vac the headroom is 20 V, 4.5%, and a network allowed to run 10% high reaches 484 Vac, which clears neither the 460 nor the 485 rung by a margin you would want to defend. Your engineer owns the margin and the policy behind it. Our post on the MOV voltage ladder shows where the steps fall across the whole range.
Which Walsin parts sit either side of a 440 Vac network?
Three sizes offer both rungs, and they differ only in voltage. All are in the export and all are Standard D series.
| Walsin part | Size | Max working | Varistor voltage | Peak current | On shelf, 23 September 2026 | Match / mismatch (440 Vac network) |
|---|---|---|---|---|---|---|
SR681K10D |
10 mm | 420 Vac | 680 Vdc | 2,500 A | No | Mismatch: below 440 Vac |
SR751K10D |
10 mm | 460 Vac | 750 Vdc | 2,500 A | No | Match on rung, mismatch on shelf; margin is yours |
SR681K14D |
14 mm | 420 Vac | 680 Vdc | 4,500 A | No | Mismatch: below 440 Vac |
SR751K14D |
14 mm | 460 Vac | 750 Vdc | 4,500 A | No | Match on rung, mismatch on shelf |
SR681K20D |
20 mm | 420 Vac | 680 Vdc | 6,500 A | No | Mismatch: below 440 Vac |
SR751K20D |
20 mm | 460 Vac | 750 Vdc | 6,500 A | No | Match on rung, mismatch on shelf |
At each size the peak-current rating is identical across the two rungs, so moving up a rung costs no surge rating in the export. It does raise the varistor voltage from 680 to 750 Vdc, which raises the voltage your downstream parts must withstand during a surge. That is a design decision, and the export cannot make it for you. Walsin states working voltage in Vac only, so any DC rating must come from Walsin, as our post on how to choose an MOV varistor explains.
Does the safety capacitor ladder have the same shape?
No, it is coarser and it is rated differently. We counted the UR column of all 929 disc capacitor rows: 137 carry an X1 rating of 440 Vac, 103 carry 500 Vac, 112 carry 400 Vac and 15 carry 760 Vac. A 440 Vac network meets a 440 Vac X1 rating at exactly its nominal value.
The 137 parts at X1 440 Vac pair that with Y2 250 Vac or Y2 300 Vac, in the AC series, its small-size variant and an automotive variant. SL0AC100J060 is a 10 pF example, and YP7AC101K060 is a 100 pF automotive example. At X1 500 Vac the real part numbers include SL5AC100J060. None of the three is on our shelf. Whether an X1 rating equal to your nominal voltage is acceptable, and which standard applies to a vessel, is for your compliance team; we hold no marine standard in our datasheets. Our post on X1/Y1 versus X1/Y2 safety capacitors covers the rating system.
What do we hold in stock for a vessel, and what do we not hold?
Nothing at the voltages above, and nothing marine. We checked our stock list as at 23 September 2026, 1,125 part numbers: it holds 0 of the 379 varistor part numbers, 0 of the 929 disc capacitor part numbers, and 3 safety capacitor lines, all MLCC. The 3 are S242B102K502CT, S252B222K502CT and S252B471K502ZT.
None of the 28 Walsin datasheets we hold, 451 pages, contains the words vessel, marine or salt. We make no marine, type-approval or classification-society claim for any part, and we hold no document that names one. The stock list is a dated snapshot and moves. The ready stock page shows what is held in Hong Kong now, and we quote part-number counts, never piece counts.
How can Venatech help a Greek ship-electronics buyer?
By crossing the surge part you already use and stating the differences. Venatech Limited is an authorised Walsin distributor in Hong Kong. Walsin is our only authorised line, and the other lines we supply are Stackpole and Viking.
- Cross-reference. Paste your incumbent number into the free cross-reference tool, which decodes 18 manufacturers’ part numbers across 800,000+ crossable parts, and read each Walsin candidate with match and mismatch stated field by field.
- BOM check. Upload a converter or switchboard bill of materials to /bom/ and have each line checked against the same engine.
- Ready stock. The ready stock list is a Hong Kong snapshot dated 23 September 2026, never live-synced.
- Service. Hong Kong-based, small lots, cross-referencing help, and a quote requested through the site. Our address is Unit 207, 2/F, Sun Ling Plaza, 30 On Kui Street, Fanling, N.T., Hong Kong, telephone (852) 2628 4777.
A worked example from our own export: a 440 Vac network with a 14 mm disc maps to SR751K14D at 460 Vac, 4,500 A, and the 420 Vac SR681K14D is the mismatch. Neither is stocked, so both are factory orders. Our varistor range lists the families. Confirm against both datasheets and qualify in your own circuit.
The short version
Greece controls 4,388 vessels by the 2026 chamber survey, and EU shore-power duties start in 2030 per To Vima. In Walsin’s varistor export the ladder runs 420 Vac then 460 Vac, 82 of 379 rows reach 440 Vac or more, and none is on our shelf. The 137 safety capacitors at X1 440 Vac are not stocked either.
Send us one surge-protection line from a shore-connection design and we will return the Walsin parts with the differences stated. If your network sits at 440 Vac, which gives way first, the rung or the margin?
Sources
Fetched 22 October 2026. The market and regulatory statements above are taken from these pages; the part data comes from our own Walsin exports and stock list.
- ELNAVI, report on the 2026 GSCC annual survey of the Greek shipping fleet, publication date not shown on the page: https://elnavi.gr/en/shippings-news/2774-greek-controlled-fleet-hits-all-time-high-in-2026-gscc-annual-survey-on-greek-shipping-fleet-statistics
- To Vima, “Cold Ironing: Greece’s Race to Green its Ports by 2028”, 14 June 2025: https://www.tovima.com/climate/cold-ironing-greeces-race-to-green-its-ports-by-2028
- Naftemporiki, “HEDNO: the installation of cold ironing in ports is progressing”, 30 January 2025: https://naftemporiki.gr/english/1898127/hedno-the-installation-of-cold-ironing-in-ports-is-progressing
Frequently asked questions
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Does Walsin offer a varistor rated 440 Vac?
No. We counted all 379 export rows: the ladder runs 420 Vac then 460 Vac, with no row at 440 Vac. 82 rows reach 440 Vac or more, and all are at 460 Vac or above. The margin over your network is your engineer’s decision.
How many Walsin varistors are rated 460 Vac?
13 rows. They are SR751K10D, SR751K14D and SR751K20D in the Standard D series, plus E, V and Industrial parts. The 5 mm and 7 mm discs stop at 420 Vac. None of the 13 is on our shelf as at 23 September 2026.
Does a higher varistor rung cost surge rating?
Not in the export. At 10, 14 and 20 mm the peak current is the same at 420 and 460 Vac: 2,500, 4,500 and 6,500 A. The varistor voltage rises from 680 to 750 Vdc. Whether that suits your downstream parts is a design decision.
Do Walsin varistors state a DC working voltage?
No. We checked all 379 rows and every working voltage is written in Vac. We hold no varistor datasheet, so a DC rating, if Walsin states one, has to come from Walsin.
Do you hold marine or classification-society approval for these parts?
No. None of the 28 Walsin datasheets we hold, 451 pages, contains the words vessel, marine or salt, and we make no type-approval claim. We offer the datasheet and lot and date-code traceability. Qualification stays with you.
Are 440 Vac X1 safety capacitors available from Hong Kong stock?
No. We counted 137 disc rows with an X1 rating of 440 Vac, and none is on the stock list as at 23 September 2026. The ready stock page shows what is held now. Whether the rating fits a vessel is for your compliance team.