Due to this symbol does this RCD have overcurrent protection?

[GerryHinkley68]

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/

 

[Lucien Nunes]

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.

 

[Dartlec]

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!

 

[Dartlec]

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.

 

[Lucien Nunes]

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.

 

[GerryHinkley68]

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!

 

[Lucien Nunes]

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.

 

[GerryHinkley68]

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.

I agree!