What codes for this EICR?

[HappyHippyDad]

I just have a question about the RCCB seen in the picture below.



It is a 63A RCCB protecting the 32A shower circuit, 32A cooker circuit and 2 x 32A socket circuits. My concern is that the rated current of the RCCB is being exceeded. Even with diversity applied it is >63A. I realise we see this often with boards like this, but to start with the RCD test button was not working and also the RCD did not trip with any tests. I then manually switched off the RCD. Following this, the test button worked and the x1 and x5 tests were satisfactory.

I feel the RCCB needs changing for a 80A and I would code it a C2. The reason being is that this is such an important device doing such an important job that I don't think we can just say "well it's highly unlikely in domestic house it will be overloaded" (even though it probably won't be), also if it got stuck open once it may do it again. Small probability of occurring, but a very high impact if it does. This leads to a fairly high score on a risk assessment.

What do you guys think?

 

[ImpededLoop]

C2 for it not working.

Possibly C3 if you were coding for it's 63A rating, provided there's no evidence of thermal damage, but how often is the shower running and the cooker running at full capacity at the same time? The ring finals may have minimal loads? .

 

[Julie.]

As a counter argument, what is the size of the incoming fuse? If that is 60A then technically how could it be overloaded?

Just because the mcbs add up beyond the rcd doesn't mean it's actually overloaded, as you say standard diversity, but is standard diversity really the case, on a typical house would both rfc and a shower really consume 63A??

I would c2 in any case as it didn't work properly, but not on the potential for overload.

 

[Julie.]

This issue of mcbs adding up is to my mind nonsense.

Sure when you had one ring, a lighting, shower and cooker circuit, standard diversity appears reasonable.

Now with pretty much the same load we have two or three lighting circuits, three rfc (upstairs, downstairs, and kitchen), etc.

We now logically break down circuits for resilience rather than load, we shouldn't really add them up based on load diversity when they weren't split for that reason.

 

[brianmoooore]

Is the RCD working properly now? I've come across plenty of RCDs that haven't tripped or been tested in decades, are reluctant to trip and even more reluctant to reset. 'Exercise' them a few times, and they come back to within spec, couple that with a strong lecture to the owner about the importance of regular testing, and no further problems.

 

[suffolkspark]

Yea as Julie mentions, if the service fuse is 63A then it's fine, I C3 if it's >63A, and C2 if thermal damage seen. Incidentally the napit codebreakers book says C2 for a type AC rcd where there could be DC currents from equipment (not a word for word quote just saw it the other day) but that's basically everywhere now.

In any case on this one it seems to have got stuck, so could do again, so I'd be inclined to C2 that and replace with a bigger one anyway.

 

[brianmoooore]

Incidentally the napit codebreakers book says C2 for a type AC rcd where there could be DC currents from equipment

IET set the regs., not Napit (or NICEIC)

 

[suffolkspark]

IET set the regs., not Napit (or NICEIC)

Well aware of that and I regularly find fault with the napit book, was just worthy of note.

 

[Pretty Mouth]

Incidentally the napit codebreakers book says C2 for a type AC rcd where there could be DC currents from equipment (not a word for word quote just saw it the other day) but that's basically everywhere now.

Interested to hear the justification (if any) NAPIT give for this, if possible?

To me, it could only be a C2 if the RCD was shown to be not working, AND lack of RCD for the protected circuits warranted a C2.

 

[HappyHippyDad]

Thanks for all the replies. It's good to hear everyone's viewpoints.

I'm going to C2 it (as it was sticking and not testing originally_ and replace it with an 80A RCCB.

Plus... I do tend to C3 any plastic consumer unit, so I will offer a new consumer unit to the customer, making it very clear that this is just a recommendation and not required for a satisfactory report. However, it will also clear the C2's!

I wonder what you guys code a plastic consumer unit? I suspect a mixture of C3's and 'no codes'.

My reasoning for coding as a C3 is because the report specifically asks about fire rating in the schedule of inspections (4.4). I can't see how you can tick this if it is not appropriately fire rated.

 

[brianmoooore]

Plastic consumer unit is always a C3, or worse, in a domestic property, if not in a fire resistant enclosure, since you wouldn't be able to fit it under the 18th.

 

[Pretty Mouth]

For me, a C3 for plastic CU, C2 if signs of thermal damage

 

[brianmoooore]

Of course it's a C2 if showing thermal damage or doesn't meet IP requirements. C1 if exposed live terminals.