Anyone know this RCD symbol?

Mark42

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• Aug 2, 2023

• #2

jjjinx said:

Hi guys,

I know the AC symbol but the one to the right i've not seen before or just not noticed it.

Anyone know?

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Well spotted. I have no idea.

At a guess, I’d say it's nothing to do with the breaking spec, e.g. pulsed dc, as that would be in the rectangular box with the ac symbol.

Could it be something as simple as Double Pole - i.e. the device breaks the neutral as well as the line? Is this maybe an old device which pre-dates the double switch symbol?

 

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newfutile

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• Aug 2, 2023

• #3

It looks like a sawtooth waveform ,it could possibly be caused by a dimmer switch.I have never seen one printed on an rcd.

 

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DefyG

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• Aug 2, 2023

• #4

Could always ask Hager as I've noticed it on another of their RCD's.

 

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kropaske

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• Aug 2, 2023

• #5

I've read about it little while ago and it's increased resistance to nuisance tripping due to various surge currents.

 

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Marvo

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• Aug 4, 2023

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Not sure but if I saw that symbol at my local beach I'd assume there's sharks in the water....

 

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Mark42

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• Aug 4, 2023

• #7

Marvo said:

Not sure but if I saw that symbol at my local beach I'd assume there's sharks in the water....

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No. It obviously means for use only in rooms with left-hand hung doors.

Serious point though: If an icon can’t be easily understood, it’s badly designed.

 

Last edited: Aug 4, 2023

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pc1966

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• Aug 4, 2023

• #8

Which model of RCD? More of the photo might help!

 

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loz2754

• Aug 4, 2023

• #9

I remember trying to find the answer to this a couple of years back. Trouble is, I can't remember whether I found the answer or not!

 

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kropaske

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• Aug 4, 2023

• #10

To be more specific shark fin/open door/saw tooth sign means RCD will resist surges 8/20μs up to 250A,
Selective type with non operating time of at least 40ms (S) will resist 8/20μs up to 5kA
Delayed type with non operating time of at least 10ms (G) will resist 8/20μs up to 3kA

 

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• Aug 18, 2023

• #11

It is nowadays extremely important. Unfortunately, the straight MFT won't test for this. Shark fin is actually a waveform of a pulse which is responsible for nuisance tripping. It is not standardized, however. German vendors will use the capital letter K, with the same meaning. I have a secret tip how to test this: make a circuit on the table being protected with the RCD under test, and apply a Martindale EZ-150 socket tester (any other won't fit!). They apply an 500 usec pulse train. If the RCD won't trip, then it is fine, otherwise avoid it or limit its use. Of course, any other tests must pass, too. There are a lot of RCDs on the market, which may not have the shark fin mark, but withstand those ugly short pulses. It is worth to select RCDs for this feature otherwise the customer may become unsatisfied.

 

Last edited: Aug 18, 2023

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telectrix

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• Aug 18, 2023

• #12

Mark42 said:

No. It obviously means for use only in rooms with left-hand hung doors.

Serious point though: If an icon can’t be easily understood, it’s badly designed.

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I though it was Katie Price from the side,

 

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