MWC for changing MCB's to RCBO's

[Boat_Boy]

I've just had a EICR completed and it has C2's for cables concealed, in walls at a depth less than 50mm, containing metal parts and no RCD(s) provided for additional protection.
All the circuits are for night storage heaters and come from a seperate DB on night tariff and where installed in early 2018.
There was limited testing due to no power to the DB because of the night tariff.
I have spoken to the electricians super and queried it asking would a MWC be issuied after the MCB's had been replaced with RCBO's as per the recommendations. I was quite surprised by his reply when I was told that a new EICR would be issued because it's more than one circuit.
I'm pretty sure this is incorrect.
Correct proceedure would be appreciated.

 

[Dave OCD]

I think the coding is OTT for off peak storage heater circuits, C3 at worst.

 

[Dartlec]

There's two slightly different issues here by the sounds of it.

Firstly, if the storage heaters are all hard wired (not via plugs/sockets) then I think a C2 is way overboard personally... Certainly the Best Practice Guide would say C3 - Are they a Napit Codebreakers addict perhaps?

Secondly, if they 'fix' it by installing RCBOs then they would need to issue a certificate for that work. If it was one RCBO then a MWC would be appropriate I think - but if there are several then an EIC might be sensible (I think you can get MWC with multiple circuits in some software options but not sure)

That raises an issue - since they can't correctly certify the RCBOs if they haven't tested the trip times on them, which sounds likely unless they were there at 1am (or rigged up a temporary supply)

Finally, it's often easier for an updated EICR to be issued which has the C2s removed. That's not essential though, since the original one plus the new certification is legally enough (though difficult to explain to non-electrical agents, etc)

So whether or not you get a new EICR, you should be getting either MWC OR EIC for the RCBO installation...

 

[timhoward]

What he said! ^^

NICEIC have previously declared that MWC is ok for changing like for like protective device or equivalent RCBO. ( Appropriate use of minor works certificates - https://professional-electrician.com/technical/appropriate-use-of-minor-works-certificates/ )

The issue here is that there are a few circuits. There is a 3 circuit MWC floating about somewhere, otherwise an IEC would be needed.
If this is a rental property then you will either need an EICR at the end (with the test results) or written evidence of repairs.

I totally agree with @Dartlec that the RCBO's need testing, and this could have been done with a bit of thought. There's also nothing stopping dead tests, and Zs by calculation. So the excuse of no power preventing testing is a little bit poor.

 

[Boat_Boy]

Thanks for your replies,

I think they are NAPIT.
As it is 4 circuits that they reckon need RCBO’s theI will be pushing for a EIC.
I have also noticed that all the other circuits, 7 in total on the DB1, have not been live tested either and yes there was power to the DB1.
This is poor as the bill was more than twice the quoted price and there was also mistakes in the circuit and overload columns.

Thanks

 

[Dartlec]

Thanks for your replies,

I think they are NAPIT.
As it is 4 circuits that they reckon need RCBO’s theI will be pushing for a EIC.
I have also noticed that all the other circuits, 7 in total on the DB1, have not been live tested either and yes there was power to the DB1.
This is poor as the bill was more than twice the quoted price and there was also mistakes in the circuit and overload columns.

Thanks

It's generally acceptable to calculate Zs using Ze + R1&R2, though obviously RCDs should be tested for trip times etc and Ze should be taken, both of which are live tests...

Sounds like another in the long line of less than ideal EICRs that get raised on here... If you want to post it with identifying information removed it might be clearer if it's just a reasonable certificate with issues, or a worthless piece of paper...

Whether it's an EIC or several MWC shouldn't affect the work that was done (or the price charged) so I'd say that's the least of the issues in this case....

 

[Boat_Boy]

I’ll try to post the EICR tomorrow.
thanks

 

[Lister1987]

I’ll try to post the EICR tomorrow.
thanks

Just remember to redact any identifiable information; both yours and the sparks.

 

[telectrix]

mwc for 3 circuits df.

 

[Boat_Boy]

Here is the redacted EICR for your comments and no it didn't come with page 9 of 9

Thanks

B

 

[Mikegh]

Storage heaters on Rcbos ?

How does that work out ?

 

[Strima]

Those C2's aren't justified IMHO.

Also:

Outside Light Damaged
Schedule Item contravened:
5.20 - Adequacy of working space/accessibility to equipment (132.12; 513.1)

How does a damaged accessory come under 5.20?

 

[timhoward]

Few minor things.
Circuit 11 Zs....
Circuit 13 Zs suggests an error or didn't tighten something somewhere after R1+R2 (Ze is 0.3)
High R1+R2 on kitchen sockets.
I'd personally label 4 storage heater breakers rather than C2 the missing labels.
Bigger things....
Outside light is just weird, would need to see.
RCD coding's are over the top, at least in terms of BPG4.

Wondering if a Hager 63A 30am RCD main switch on DB2 is the quickest/easiest/most economical solution?

 

[Boat_Boy]

Thanks for your replies,
I think they are a little OTT on it as well.
The outside light is a little to the right above the lintel of the front door and is not connected to any circuits.
Storage heaters are hard wired.
I suppose using RCBO's on each circuit would leave the other circuits working if a fault developed, but not offered as an remedial option.

Thanks for yor help so far.

B

 

[loz2754]

0.3 ohms Ze does not tally with pscc of 3kA