Discuss Due to this symbol does this RCD have overcurrent protection? in the Electrical Forum area at ElectriciansForums.net

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Hello, I’ve not come across this symbol on an RCD before. It is the rectangle box with a line through the middle, which means fuse. Could this mean that the RCD could be fused to 80a? If that’s the case I know it would be classed as an RCBO but definitely doesn’t look like one! If it isn’t fused/doesn’t have overcurrent protection it would need upgrading to a 100a rated RCD because the cut out fuse is 100a. Thank you in advance.... (I cannot upload a picture so have had to find one the same on the internet).
https://willrose-electrical.co.uk/p...0ma-double-pole-80a-lexic-trip-legrand-r8030/
 
That is just an RCD, not an RCBO. As you suspect, the 80A is its current rating, not a tripping current. Im is the making current and 10kA the breaking capacity when backed up with a suitable fuse or M10 rated OCPD*. On an RCBO the In rating and characteristic curve will both be shown, and the schematic will show the thermal and magnetic tripping elements.

* E2A, that I think must be 100A or less. Therefore I believe that if the supply fault current is less than 10kA and the RCD is protected against overload downstream (e.g. by feeding circuits with a total In <100A) then a 100A BS88 fuse upstream fully protects the RCD. If the total load In >100A then this specific case doesn't apply.
 
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If you mean the one that has 10000 next to it on the linked RCD, then I believe it means the breaking rating in Amps. Or the largest number it can take on a fault and still function.

Used mostly when checking whether it can cope with the pfcc/pscc in a given installation. (Though Type testing usually ups it to 16kA for a consumer unit assembly)

Edit: Beaten to it by Lucien!
 
What loads will be going on the RCD? You are not supposed to solely use diversity factors (536.4.202) but if you only have 2 x 32A and 1 x 6A on it then you could use an 80A RCD. (depending on Manufacturers instructions)

Hager fairly recently starting putting 100A RCDs in all their premade domestic boards fairly recently citing a regulation, but there are still plenty of manufacturers selling dual RCD boards with 80A RCDs.

This document sums it up fairly well for Hager, but not sure what other manufacturers specify.
 
Good, that tallies with my observation above. 536.4.202 is the new bit that rules out relying on diversity, which was historically exploited for main switches and RCDs.
 
Thank you very much for the helpful responses. The total load going on the RCD is 92A. I believe it would have once been suitable until someone added a 16A radial for a garage feed. I will recommend that this RCD is uprated to 100A. Thanks again everyone!
 
If you mean the total In of the downstream breakers is 92A, certainly in a domestic situation it is most unlikely to see anywhere near that and it would pain me to code it, but on paper it's not compliant.
 

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