Settle an argument please.

[westward10]

How ironic someone finds an apparent Code 2 then rectified it by leaving at least one Code 2 in itself, absolutely unbelievable.

 

[Simon47]

In the board was a 40amp mcb. This was connected with 6mm EV ultra cable.

Is this the cable ?

Rated at 58 amp

It's not as simple as that !
Since it's thermosetting, I assume table 4E2A would apply, and that does indeed say the cable is rated at 58A (6mm2 and clipped direct). But you have to read the notes, and in particular :
"1. Where it is intended to connect the cables in this table to equipment or accessories designed to operate at a temperature lower than the maximum operating temperature of the cable, the cables should be rated at the maximum operating temperature of the equipment or accessory (see Regulation 512.1.5)."
The EV point may or may not be so rated, but your CU and MCB almost certainly won't be. Therefore you need to downrate the cable - which means it'll actually only be rated the same as a thermoplastic cable to 70˚C (table 4D2A) where you'll find 6mm2 is rated to 46A.

So this week come EICR the electrician insisted on replacing the 40amp mcb with a 32 amp because the cable is only 6mm. EV sparky insists 40amp is OK. Who is right here?

Based on the above, I think the EV guy is right. But regardless, the EICR guy is wrong, absolutely no doubt just plain wrong and will now find himself paying for that.

Not impressed by the move the EICR chap did either. He didn’t have an NH compatible mcb so did some cutting to the box to make it fit. It now sits higher by 5mm than the RCBO’s and main switch and the gap below has a bit of plastic glued in.

Did he provide you with a certificate for that work ? If not demand one from him - if he is a member of one of the registration schemes (e.g. NICEIC) then I believe their rules make compliance with BS7671 mandatory. BS7671 says a certificate should be provided for any works.
Of course, to provide that he'll need to sign that the work he did complied with BS7671 - at which point he's guilty of fraud.

But regardless of whether you get a certificate from him, tell him he's coming back and a) replacing the MCB he took out, and b) replacing the front cover he vandalised to make a different one fit. As previously mentioned, BS7671 is clear that in a domestic environment, the CU must be a type approved assembly - which in practice means only using parts approved by that manufacturer for use in that board. To the best of my knowledge, no manufacturer certified a different manufacturer's breakers for "mix-n-match" in their boards.
"421.1.201 Within domestic (household) premises, consumer units and similar switchgear assemblies shall comply with BS EN 61439-3 and ..."

You may get "some resistance" from him, but your EICR guy is 100% in the wrong on fitting a different make/type of MCB. Regardless of whether there is a reason for downsizing the rating, the only acceptable action is fitting the correct breaker for the board. If he refuses to fix that, make it clear that you'll report him to both Trading Standards and his registration scheme for dangerous work.
As to whether it should be 32A or 40A, you can reasonably expect him to give a reason - it will be interesting to see what he comes up with. Bear in mind, we haven't seen the installation so are assuming (based on the description) installation method C "clipped direct" - it is possible that a different method may apply, but I think that's unlikely from your description.

Appendix 4 Section 2.4 gives the derating factor for stranded conductors as 0.95, so the rating of 46A from table 4D2A needs reducing to 43.7A. There's no derating for an MCB (there is for a fuse), so as 43.7 is higher than 40, that circuit would appear to be correctly designed.

 

[Phill104]

Miffed?
i would be really pi55ed off about that if someone had done that to my perfectly good board in the name of electrical safety.
Unfortunately there are electricians out there that do not have a good understanding of the regulations and the thought that goes into making them.

instead of properly learning the trade and how to do it well they instead use some rule of thumb figures that they have "learnt" over the years and now believe them to be gospel.
here are some examples.

1mm-not suitable for domestic lighting anymore.
it is perfectly acceptable providing the load and distances are within limits

1.5mm-10A
some cables (mi) can take up to 23A in 1.5mm
20A is still possible with twin and earth if it is clipped direct.

Thanks James. I do have a background in electrical work. That was design and prototyping of switchgear as well as similar with battery backup systems for the rail, telecom and oil industries. All high current but often DC stuff. It has been a long time since I studied the regs (16th edition) and have never worked in the home arena having switched to working in IT in the late 90s. So while my knowledge is sound, I am very out of date and unfamiliar with how things are done in the home environment. Having said that, cable ratings were always a very important part of the design process as I am sure you know. A simple cock up in the choice of cable insulation could have cost us dearly.

 

[westward10]

Any individual who does that to a consumer unit should not be carrying out EICRs because they clearly do not understand the requirements of BS7671. I would like to meet this person.

 

[Phill104]

Is this the cable ?

It's not as simple as that !
Since it's thermosetting, I assume table 4E2A would apply, and that does indeed say the cable is rated at 58A (6mm2 and clipped direct). But you have to read the notes, and in particular :
"1. Where it is intended to connect the cables in this table to equipment or accessories designed to operate at a temperature lower than the maximum operating temperature of the cable, the cables should be rated at the maximum operating temperature of the equipment or accessory (see Regulation 512.1.5)."
The EV point may or may not be so rated, but your CU and MCB almost certainly won't be. Therefore you need to downrate the cable - which means it'll actually only be rated the same as a thermoplastic cable to 70˚C (table 4D2A) where you'll find 6mm2 is rated to 46A.

Based on the above, I think the EV guy is right. But regardless, the EICR guy is wrong, absolutely no doubt just plain wrong and will now find himself paying for that.

Did he provide you with a certificate for that work ? If not demand one from him - if he is a member of one of the registration schemes (e.g. NICEIC) then I believe their rules make compliance with BS7671 mandatory. BS7671 says a certificate should be provided for any works.
Of course, to provide that he'll need to sign that the work he did complied with BS7671 - at which point he's guilty of fraud.

But regardless of whether you get a certificate from him, tell him he's coming back and a) replacing the MCB he took out, and b) replacing the front cover he vandalised to make a different one fit. As previously mentioned, BS7671 is clear that in a domestic environment, the CU must be a type approved assembly - which in practice means only using parts approved by that manufacturer for use in that board. To the best of my knowledge, no manufacturer certified a different manufacturer's breakers for "mix-n-match" in their boards.
"421.1.201 Within domestic (household) premises, consumer units and similar switchgear assemblies shall comply with BS EN 61439-3 and ..."

You may get "some resistance" from him, but your EICR guy is 100% in the wrong on fitting a different make/type of MCB. Regardless of whether there is a reason for downsizing the rating, the only acceptable action is fitting the correct breaker for the board. If he refuses to fix that, make it clear that you'll report him to both Trading Standards and his registration scheme for dangerous work.
As to whether it should be 32A or 40A, you can reasonably expect him to give a reason - it will be interesting to see what he comes up with. Bear in mind, we haven't seen the installation so are assuming (based on the description) installation method C "clipped direct" - it is possible that a different method may apply, but I think that's unlikely from your description.

Appendix 4 Section 2.4 gives the derating factor for stranded conductors as 0.95, so the rating of 46A from table 4D2A needs reducing to 43.7A. There's no derating for an MCB (there is for a fuse), so as 43.7 is higher than 40, that circuit would appear to be correctly designed.

Thank you for your detailed response. That will be really helpful in my complaint. Just for the record, here is a pic of the cable and how it is clipped.

 

[James]

Thanks James. I do have a background in electrical work. That was design and prototyping of switchgear as well as similar with battery backup systems for the rail, telecom and oil industries. All high current but often DC stuff. It has been a long time since I studied the regs (16th edition) and have never worked in the home arena having switched to working in IT in the late 90s. So while my knowledge is sound, I am very out of date and unfamiliar with how things are done in the home environment. Having said that, cable ratings were always a very important part of the design process as I am sure you know. A simple cock up in the choice of cable insulation could have cost us dearly.

Lets face it, cables have been pretty much the same for the last 30 years at least.
copper has not magically reduced is resistance so it generates the same amount of heat as it always has.
some improvements in insulation materials have happened but are not massive and may well not affect you in this circumstance.
in my opinion, the inspecting engineer has fcucked up either by human error or poor training.
you have a great argument that is backed by the reg's to have it repaired correctly at his expense in my opinion.

 

[loz2754]

Any individual who does that to a consumer unit should not be carrying out EICRs because they clearly do not understand the requirements of BS7671. I would like to meet this person.

I'll come with you...

 

[davesparks]

I wasn’t at home during the inspection, SWMBO was and paid for the extra work.

I’ve taken a pic, but the pointless bit of plastic seems to have fallen off. It is inside the house so now danger of getting rained on. Having said that, as is often the case the architect slapped the bathroom directly above. Sometimes architects need a kid hard kick in the love spuds.

Jesus christ, I'd say you have a case for pressing a charge of criminal damage there!

 

[Simon47]

Well probably not since SWMBO presumably gave permission for the "repair". So although the work was clearly ... err "substandard", it wouldn't be criminal damage.

 

[Simon47]

Just for the record, here is a pic of the cable and how it is clipped.

That's fine along the run, it's things like "does it pass through thermal insulation in the wall ? Not that it would alter things since it would be a) a short distance affected, and b) away from the connections at each end the cable could be used at it's full 90˚C rating.

 

[davesparks]

Well probably not since SWMBO presumably gave permission for the "repair". So although the work was clearly ... err "substandard", it wouldn't be criminal damage.

I very much doubt that SWMBO gave permission for a complaint installation to be made non-compliant and dangerous.

The installation has been changed from being compliant and safe to being non-compliant, the person responsible must be punished to the full extent of the law.

 

[Phill104]

That's fine along the run, it's things like "does it pass through thermal insulation in the wall ? Not that it would alter things since it would be a) a short distance affected, and b) away from the connections at each end the cable could be used at it's full 90˚C rating.

I wish I had thermal insulation. Typical early late 1970s /1980s cheap build. Breeze block, gap, brick with nothing in between. But yes, it is a very short distance. I am sure you can appreciate it is late at night and chucking it down so taking pics is challenging at best.

 

[Phill104]

I very much doubt that SWMBO gave permission for a complaint installation to be made non-compliant and dangerous.

The installation has been changed from being compliant and safe to being non-compliant, the person responsible must be punished to the full extent of the law.

SWMBO has zero idea about electrics, and why would she as it is way outside her area of expertise being a medical professional. She had to rely on the expertise, or lack, of the electrician that attended.

 

[Phill104]

How ironic someone finds an apparent Code 2 then rectified it by leaving at least one Code 2 in itself, absolutely unbelievable.

I would suggest it is a sad indictment of the current state of the industry regulation at the moment. I know there are many brilliant electricians out there who really do know their game. There does seem to be a trend of electrician’s doing bread and butter work such as EICR, PAT testing and EV charger installations for motor brands at a cheap and rushed price. It makes me wonder if these electricians loose the skills and knowledge they should have learnt because of the lack of doing a multitude of work. Just some thoughts as an outsider, albeit one with outdated electrical knowledge outside of domestic environments, so what would I know.

Just to add why I have some of these thoughts I will mention something that happened a year ago. My bosses boss had a summer house built in his garden. He was retiring and wanted somewhere to spend time. He hired an electrician to install lighting and electricity there. So an armoured spur was run inside ducting. This went to a small consumer unit in the summer house. The day after the install my bosses boss was looking at it and noticed a big hole in the front of the consumer unit. Being a bit daft and having what can only be described as having a senior moment, he put his finger through the hole. Yes, the inevitable happened. He was OK but shared a picture of the consumer unit with us all. Seems the electrician had signed off the install but did not put any blanks in the three spare ways. Even with the poor phone shot I could see the bare bus bar inside. I appreciate mistakes do happen, but that seems a fundamental basic. For me it was more the blase way his electrician responded to his complaint. He wasn’t happy about having to return to fix what to him was something so trivial. The sparkies comment “You should never have to open the cover anyway” in his email to my bosses bos lead me to a couple of seconds of sweary rant.

 

[Simon47]

It's all very well moaning about cut price jobs - but the reality is that the bulk of the population don't know much/anything about <pick whatever trade you like> and will choose on price. So unless you are lucky enough to work in an area (location) where there's a shortage, or where there's a higher than average proportion of "good" customers (the ones that consider value rather than price), then you have to climb down (at least partially) to the level that others have set.
And that always leads to a race to the bottom of the pond. No amount of regulation would fix it, in part because the cost of compliance would drive more of the better tradespeople out than it would of the bottom dwellers.