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Rocker switch

I have a disc sander that the switch has broken on and I have been looking for a replacement, but I am confused by the different specs.

The spec of the switch as written on the side of it is -

Jin Ding

FB 3-4

8(8) A 125V~5e4

6(4) A 250V~5e4

I have not found anything of the exact same spec, they all seem to have one of the amp amounts different.

Can someone please explain the spec to me, especially the numbers in the brackets, and suggest a safe replacement?

Thank you.



0 Votes


May 13, 2019 10:42

My suggestion is to try searching for the sander make and model followed by "switch" or "spares" this should make the process simpler as there are many different mechanical sizes and locking/fixing features which will make it difficult to replace.

Regarding the switch spec, my understanding is
8(8) A 125V this will switch a resistive current of 8A and an inductive load such as a motor at (8A) when in a 125VAC circuit.
6(4) A 250V The current ratings drop to 6A resistive and 4A inductive at 250VAC, the reason for the reduction is to ensure the arc produced when switching is extinguished as the contacts break (they have a fixed separation gap) and this is affected by both voltage and the type of load.

I do not know what the 5e4 refers to, so interested in what others reply.

The make is obviously Jin Ding and the FB3-4 is the part number, but I failed to find anything as you did.
You could use the search tool at RS and narrow the search by the size, number of contacts/type, current rating 6A at 250VAC and see if anything results which is suitable.

May 14, 2019 07:29

@Boss Thank you for your answer. I have tried searching for make and model specific replacements, but the company that deals with it for Lidl, it is a Parkside disc sander, said the switch was an integral part and that the whole thing would need to be returned, however switches are not covered by the warranty. I opened up the disc sander and the switch is connected by spade connectors and is not integrated. I asked at another website and this was the answer "As far as I'm aware it's fine to replace a component with one that has the same or higher amperage rating, so you should be fine. Definitely worth checking sizes though." Would you know if this is accurate? Thanks again for answering, I have tried various places, reddit etc and the question does not even get posted.

May 16, 2019 08:36

@acoustic yes, match or better the current ratings you quote in the original post, so for UK 250VAC 6A or more for resistive load and/or 4A or more for inductive loads such as your motor. My view is you can often 'upgrade' commercial products like this when parts break and increasing the current rating should increase the life of the new switch regarding contact life. If you find a switch that mechanically will fit you can post the part details for confirmation.

May 13, 2019 10:42

Just to add I looked up as an example and the tech spec stated "In the specifi cation of the reference power using the bracket notation, e.g. 16 (4) A 250 V AC, the value in front of the brackets indicates the switch-off current and the value in brackets the nominal motor current." which confirms the bracketed current. However, this particular switch would not be a suitable replacement as it spec'd 6 (2) A 250 V AC 1E4 The 5e4 was also defined "... our switches meets these requirements and is marked by the 5E4 symbol (50 000 switching cycles)" So hope this helps with your search.