DIY vs Professional

[scousespark]

Its great to read that you are trying to get ahead of the game re testing your own work. Most would just wait.

Ive never heard of a "private building control firm". To comply with BC you notify before you start or use a registered electrician. The 3rd party test firm sign off for testing but dont notify your job.

 

[JohnW2]

Ive never heard of a "private building control firm".

They exist...

To comply with BC you notify before you start or use a registered electrician.

If one is not using a self-certifying electrician, one has to notify the "Building Control Body" before one starts - but that does not have to be the local authority's BC body.

The Following are key terms used in this document:
Building control body
A local authority or private secor approved inspector

Kind Regards, John

 

[JohnW2]

Ive never heard of a "private building control firm".

Further to what I recently wrote, in case you ever have a need, clicking here will take you to a directory of private sector "building control approved inspectors" (aka "private sector Building Control Bodies").

Kind Regards, John

 

[SimonH2]

Finally on the point earlier about the fused spur. I think I'm still failing to explain - see simplified diagram below. The problem was that in a 32Amp circuit, a flex had been used to create an un-fused supply from the back of an existing socket to supply a Fused Switch unit that then provided a 13amp fuse to protect the boiler connection via its 13amp flex. Surely I am not going nuts thinking that is dangerous?

The regs do allow for such an arrangement subject to certain restrictions - which I can't recall offhand, but does specifically limit the length of the reduced cross section cable.
As pointed out, as long as the "thin" cable is sufficiently short (one of the criteria for being allowed) then it's resistance should be low enough that fault protection is still OK. Ie, if you stick a nail through it at the load end, then the current will still be high enough to trip the B32 MCB protecting the circuit.
The chances of creating a "fault" which pulls enough current to damage the cable, but without tripping the MCB was "vanishingly small". In practical terms, there's be enough current through the "fault" for it to be a small arc furnace generating many kW of heat - and it would be much the same whether it is the 1mm² cable you have, or a 2.5mm² cable. In additional, such an arc furnace would quickly convert into a solid short - or blow itself open circuit.
Once you reach the FCU, then the fuse in that will protect both the downstream cable AND the upstream cable from simple overloads.

 

[EFLImpudence]

The regs do allow for such an arrangement subject to certain restrictions - which I can't recall offhand, but does specifically limit the length of the reduced cross section cable.

That length limit - plus fire protection - only applies if it is NOT adequate for the fault protection.

As pointed out, as long as the "thin" cable is sufficiently short (one of the criteria for being allowed) then it's resistance should be low enough that fault protection is still OK. Ie, if you stick a nail through it at the load end, then the current will still be high enough to trip the B32 MCB protecting the circuit.

If the resistance and withstand is compliant, there is no length limit.
Don't forget 2.5mm² only has 1.5mm² CPC - used to be 1mm²

 

[Not An Electrician]

The calcs and theory are where I am very weak. I'd never thought about a fuse acting "in either direction" - but have thought of it more like a safety valve - but I guess the same is true of that! So I probably ought to look out some good theory books to get to grips with that and the calcs - I tend to start with the practical logic and go from there so its the bit I find hardest! Any recommendations on accessible theory web pages or books?

 

[scousespark]

They exist... If one is not using a self-certifying electrician, one has to notify the "Building Control Body" before one starts - but that does not have to be the local authority's BC body.



Kind Regards, John

I am aware of the CIC scheme, but was confused by OP saying the firm had recommended a firm to carry out testing.
I was under the impression that LA or private BC work the same and they take responsibilty for testing. I have no experience when it comes to this notification route.

 

[JohnW2]

I was under the impression that LA or private BC work the same ....

Indeed, but don't many/most LAs 'contract out' the testing - so, as you say, one might expect that at least some private BC bodies would "work the same"?

I suspect that many/most LABCs, and probably also many/most private BC bodies, probably don't have an in-house capability for undertaking testing of electrical installations. Their expertise obviously lies primarily in areas other than electrical - and, indeed, prior to 2005 had no involvement with electrical installations.

Kind Regards, John

 

[scousespark]

Indeed, but don't many/most LAs 'contract out' the testing - so, as you say, one might expect that at least some private BC bodies would "work the same"?

I suspect that many/most LABCs, and probably also many/most private BC bodies, probably don't have an in-house capability for undertaking testing of electrical installations. Their expertise obviously lies primarily in areas other than electrical - and, indeed, prior to 2005 had no involvement with electrical installations.

Kind Regards, John

If the BC sub-contracts the electrical testing don't the retain responsibilty. I didn't think they left it to the customer to sort out.

 

[JohnW2]

If the BC sub-contracts the electrical testing don't the retain responsibilty. I didn't think they left it to the customer to sort out.

I'm not sure that they did 'leave the customer to sort it out'. Are you sure that you're not over-interpreting "... the firm had recommended a firm to carry out testing"? Could he perhaps have meant that the BC body had 'appointed' a firm to do the testing, or something like that?

Kind Regards, John

 

[scousespark]

Maybe Not An Electrician ciuld clear this up. Just now this just us guessing what he or she means.

 

[JohnW2]

Maybe Not An Electrician ciuld clear this up. Just now this just us guessing what he or she means.

Indeed we are. As you say, maybe we will get some clarification.

Kind Regards, John

 

[SimonH2]

Indeed, but don't many/most LAs 'contract out' the testing ...

I assume very few (if any) actually have in-house capability. Mine quote two prices for minor electrical works - one if you provide them with acceptable test results, a higher one (about the cost of getting an EICR done) if you can't.

I recall back when the 2005 BRs came in, there being some discussions in the professional community as to how to handle such tests. The electrician could not "certify" the installation as only the BC dept has that power, and IIRC the consensus was to do an EICR as that was the only "official" paperwork route open to them. Given a satisfactory EICR, the BC dept could then issue a completion certificate.

As for Scoursespark's comment about responsibility, I guess BC have to stand behind their completion certificate. However, if it turned out that there was something seriously wrong with the installation it would come down to a "discussion" as to whether it was something the sparky could/should have reasonably seen during the inspection - and if so, then I guess potentially he could end up getting the benefit of all those PI premiums. Hard to see where a problem could end up in the sparky's hands unless a) something serious happened, and b) it could be shown that he really really should have seem something that was wrong.

 

[JohnW2]

I assume very few (if any) actually have in-house capability.

Indeed. As I said.

Mine quote two prices for minor electrical works - one if you provide them with acceptable test results, a higher one (about the cost of getting an EICR done) if you can't.

What about "inspection" - I presume that they don't have an in-house capability/expertise to do that, either?

I recall back when the 2005 BRs came in, there being some discussions in the professional community as to how to handle such tests. The electrician could not "certify" the installation as only the BC dept has that power, and IIRC the consensus was to do an EICR as that was the only "official" paperwork route open to them. Given a satisfactory EICR, the BC dept could then issue a completion certificate.

As often discussed, the problem with an 'after the event' EICR is that it does not provide the LA with confirmation that 'hidden' parts of the work have been undertaken satisfactorily/compliantly.

As for Scoursespark's comment about responsibility, I guess BC have to stand behind their completion certificate. However, if it turned out that there was something seriously wrong with the installation it would come down to a "discussion" as to whether it was something the sparky could/should have reasonably seen during the inspection - and if so, then I guess potentially he could end up getting the benefit of all those PI premiums.

Indeed. I did not bother to quiz him, but I was not quite sure what he meant by 'responsibility'. As you say, they are 'responsible' for issuing a Completion Certificate 'in good faith' on the basis of testing etc. information provided to them. However, provided they could demonstrate that they had taken reasonable steps to subcontract the testing to a competent person/firm, I'm not sure that they would be 'held responsible' for the quality of the testing that they had sub-contracted. As you say, if it ever transpired that there was an issue relating to the subcontracted testing, I presume that would be a matter to be resolved between the LA and the tester. However, as you imply, it's very unlikely that this situation would ever arise. Unless something catastrophic happened, I doubt that an LA would have the capability/expertise to detect anything wrong with the testing that had been done for them.

Kind Regards, John

 

[SimonH2]

... the problem with an 'after the event' EICR is that it does not provide the LA with confirmation that 'hidden' parts of the work have been undertaken satisfactorily/compliantly.

I suspect that they may want to look at (eg) first fix and they can probably tell themselves if something "looks right". I don't know how they do that side of things as I've only done a BR application for a CU change.
When I was making an opening in a structural wall, the guy came and had a look when I'd got the lintel and cupboard floor in place (ie before I covered anything), then a final look when it was finished.