Surge and Safety Parts for Denmark: The 575 Vac Hole in Walsin’s Varistor Ladder

If you are choosing surge protection parts for Denmark on a 690 V class system, check the 575 Vac step before you commit. Walsin Technology (Walsin) publishes three part numbers at 575 Vac, on two footprints, with a floor of 40,000 A. At 550 Vac and at 625 Vac it publishes thirteen each, on nine footprints, from 2,500 A up.

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Venatech Limited, an authorised Walsin distributor in Hong Kong, holds Walsin’s varistor parametric export of 379 rows and its disc capacitor export of 929 rows. This post is written from those two files. Every part number below is real and every count is a count of part numbers, not pieces. The reader we have in mind is a Danish engineer working on wind converter auxiliaries, marine or offshore electronics — high surge exposure, salt air, condensation, and a working voltage that is not 230 V.

Does Venatech have a Danish entity or Danish stock?

No. The operating entities are Venatech Limited in Hong Kong, the Shenzhen trading entity, VENATECH PTE LTD in Singapore and the Jiangmen factory in Guangdong, with Chengdu in preparation. Hong Kong is the authorised Walsin distribution entity and the origin of any Danish shipment. There is no Danish office, no Danish warehouse and no local stock.

What we can do from Hong Kong is read the manufacturer’s data properly and tell you where it thins out. On a 690 V class design it thins out in one specific place.

What happens to the varistor range at 575 Vac?

It very nearly disappears. The 575 Vac step, which pairs with a 950 Vdc varistor voltage, holds three part numbers in the entire export — two on the 34 mm square footprint and one on the 53 mm disc. Both of its neighbours hold thirteen.

Working voltage	Varistor voltage	Part numbers	Footprints	Lowest peak current	Match / mismatch vs a full voltage step
550 Vac	910 Vdc	13	9	2,500 A	Match — 10, 14, 18, 20, 25, 32, 34 square, 40, 53 mm
575 Vac	950 Vdc	3	2	40,000 A	Mismatch — Industrial only, nothing below 34 mm square
625 Vac	1000 Vdc	13	9	2,500 A	Match — 10, 14, 18, 20, 25, 32, 34 square, 40, 53 mm

Unique to Venatech’s data. The 575 Vac / 950 Vdc step in Walsin’s 379-row varistor export is a near-void. It holds exactly three part numbers — SR951K34R at 40,000 A, SR951K34RD at 80,000 A and SR951K53D at 70,000 A — all Industrial, on just two footprints, with no part below 40,000 A and nothing smaller than a 34 mm square disc. The 550 Vac step below it and the 625 Vac step above it each hold thirteen part numbers across nine footprints, starting at 2,500 A on a 10 mm disc. The gap is invisible in a filtered search, because a search for 575 Vac returns three perfectly valid parts and tells you nothing about the fact that the step either side of it is four times wider.

Here is what that looks like part by part.

Part number	Working voltage	Varistor voltage	Footprint	Peak current	Match / mismatch vs a 10 mm board position
SR911K10D	550 Vac	910 Vdc	10 mm	2,500 A	Match — a 10 mm part exists at 550 Vac
SR951K34R	575 Vac	950 Vdc	34 mm square	40,000 A	Mismatch — no 10 mm part exists at 575 Vac
SR951K34RD	575 Vac	950 Vdc	34 mm square	80,000 A	Mismatch — no 10 mm part exists at 575 Vac
SR951K53D	575 Vac	950 Vdc	53 mm	70,000 A	Mismatch — no 10 mm part exists at 575 Vac
SR102K10D	625 Vac	1000 Vdc	10 mm	2,500 A	Match — a 10 mm part exists at 625 Vac

What should I select instead if 575 Vac is my working voltage?

Go up to 625 Vac, not down to 550 Vac. At 625 Vac the whole nine-footprint set reappears and the varistor voltage rises to 1000 Vdc, so you keep margin on the continuous voltage rather than losing it. SR102K10D at 10 mm, SR102K14E at 14 mm and 8,000 A, and SR102K32D at 32 mm and 30,000 A are all in that set.

Choosing 550 Vac instead moves your continuous rating the wrong way. The point of looking at the 575 Vac step at all is that it sits close to a 690 V class system’s derated working voltage, and the only parts there are Industrial discs in the 40,000 A class.

Part number	Footprint	Working voltage	Peak current	Match / mismatch for a 690 V class auxiliary
SR911K14E	14 mm	550 Vac	8,000 A	Mismatch — lower continuous rating than 575 Vac
SR951K34RD	34 mm square	575 Vac	80,000 A	Match on voltage — mismatch on board area
SR102K14E	14 mm	625 Vac	8,000 A	Match — margin above 575 Vac, 14 mm footprint
SR102K53D	53 mm	625 Vac	70,000 A	Match — highest footprint at 625 Vac

What safety capacitor exists above 500 Vac?

Fifteen part numbers, one rating, two dielectrics. Across the 929-row disc capacitor export only the AS series carries an X1 rating above 500 Vac, at X1-760Vac / Y1-500Vac. That is 15 of 929 rows, or 1.6 per cent of the file, and it is the whole selection.

Part number	Dielectric	Capacitance	Tolerance	Match / mismatch vs a Class I option
YP0AS101K070	Y5P	100 pF	±10%	Mismatch — Class II, no Class I SL part exists at 760 Vac
YP0AS102K110	Y5P	1000 pF	±10%	Mismatch — Class II, larger body code
YU0AS102M080	Y5U	1000 pF	±20%	Mismatch — Class II, ±20%, same value as the row above
YU0AS472M140	Y5U	4700 pF	±20%	Mismatch — Class II, highest value in the series

That the 760 Vac group has no Class I SL dielectric, and that YU0AS103M190 disagrees with its own capacitance code, are both ours and already published. The class decode is in X1/Y1 vs X1/Y2 safety capacitors.

What does the data say about humidity, salt and temperature?

Nothing at all, and that is the measurement. We counted the declared columns in both exports: the varistor file has 10 and the disc capacitor file has 11, for 21 in total. Eight of those 21 are empty on every row — Packing, SPQ and MOQ on all 379 varistor rows, and T.C., Lead Spacing, Packing, SPQ and MOQ on all 929 disc rows. Thirteen columns carry data.

Unique to Venatech’s data. Not one of the 21 declared columns across Walsin’s varistor and disc capacitor parametric exports describes an environmental limit. There is no operating temperature range, no storage temperature, no humidity or damp-heat figure, no climatic category, no insulation resistance, no coating or encapsulation field and no ingress designation — these are not empty columns, they are absent columns. Eight of the 21 columns that do exist are empty on every row. So for a Danish marine or offshore design, the two parameters that most often decide a part in that environment are the two the parametric view cannot express, and a filtered search cannot screen on either.

For a condensing, salt-laden environment that is the governing constraint on what we can tell you. A varistor’s and a Y capacitor’s behaviour under damp heat is a datasheet and qualification question, and the parametric file does not touch it.

Do you hold a Walsin varistor or disc capacitor datasheet?

No. Venatech holds no Walsin MOV datasheet and no Walsin disc capacitor datasheet, and no public datasheet URL for either line. The datasheet PDFs we hold cover MLCC and chip resistors only.

What does Venatech add for a Danish build?

Three things. First, the counts above: a manufacturer’s search box will happily return the three 575 Vac parts without ever telling you that the voltage step either side is four times wider, and no selector tells you that an environmental screen is impossible on this data. Second, an honest map of what we do not hold, so the figures that need a certificate behind them are marked rather than quoted. Third, a dated snapshot of what is physically in Hong Kong, so selection and availability are settled in one exchange.

We will not tell you a part is equivalent. We will show you where it differs, field by field, and the qualification decision stays with you. The varistor range is on the Walsin varistor range page, and the series split is in MOV varistor series selection: D, E, V and Industrial.

The short version

The 575 Vac step in Walsin’s varistor range is three part numbers on two footprints with a 40,000 A floor, while 550 Vac and 625 Vac each hold thirteen across nine footprints from 2,500 A. For a 690 V class Danish design, 625 Vac is the step that keeps your footprint options and your voltage margin. Above 500 Vac the safety capacitor selection is 15 of 929 disc parts, all X1-760Vac / Y1-500Vac, all Class II. And across 21 declared columns in the two exports there is no temperature, humidity or coating field at all.

Tell us the working voltage and the environment, and we will tell you which part numbers exist at that voltage, how wide the step either side of it is, and exactly which of your questions the manufacturer’s data cannot answer. For a Danish ship-to, ask for the delivery term and the lead time in the same message — everything moves from Hong Kong.

Faster than an email. The cross-reference tool takes a pasted list or a spreadsheet and returns Walsin candidates field by field, differences included. Ready stock shows what is physically in Hong Kong as a dated snapshot, so you can see whether a line is a stock pull or a production slot. Qualification stays with you.

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Frequently asked questions

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Three ways to get this answered today

1. Cross a part, free. Paste up to 500 part numbers, or drop an Excel or CSV file, into the free cross-reference tool. It is matched against Walsin’s published catalogue and returns candidates field by field, with every difference from your original stated rather than hidden. Filter by commercial or automotive grade, or for soft termination, high temperature, safety certified, high Q / low ESR or low profile. There is no login and no charge.

2. Send the whole BOM. Upload a BOM and request a quote and we will come back line by line — including the lines we cannot help with, which is usually the more useful half of the answer.

3. Check the shelf before you commit. Ready stock shows what was physically in Hong Kong as at 23 September 2026. It is a dated snapshot, never a live feed, and quantities are never permanent.

Why take our word for any of this? Don’t — check it.

Venatech Limited (威納電子有限公司) is an authorised Walsin Technology distributor in Hong Kong. Confirm that with Walsin rather than with us. On the safety capacitor series we hold UL file E182369, which is searchable in UL’s own public database, together with TUV certificates R50381780 and R50195920 and CQC CQC20001280137 and CQC20001280136, against EN 60384-14:2023, IEC 60384-14:2023 and UL 60384-14. We hold 28 Walsin datasheets, 451 pages, and we will send the one covering your part number. Shipments arrive in original sealed Walsin packaging with lot and date-code traceability, and a certificate of conformity is available per shipment on request.

We will also tell you what we do not hold, which no competitor publishes. REACH, SVHC, conflict minerals, PFAS, China RoHS, ISO 9001, IATF 16949, PPAP, IMDS and a Declaration of Conformity appear nowhere in those 451 pages. You would rather hear that from us now than from your own supplier-approval team later. AEC-Q200 is compliant in Walsin’s own words and never certified, we hold no manufacturer’s end-of-life or allocation list for any brand, and qualification in your own circuit stays with you. We will not tell you a part is equivalent. We will show you where it differs.

Venatech Limited · Unit 207, 2/F, Sun Ling Plaza, 30 On Kui Street, Fanling, N.T., Hong Kong · (852) 2628 4777 · Hong Kong, Shenzhen, Singapore and Jiangmen, with Chengdu in preparation.