Jeremy Harris

This really shows a level of ignorance on the part of whoever makes these rules that is beyond belief. It is very easy to ensure that a battery system never exports to the grid, and apart from anything else, very few domestic consumers would ever want their precious stored energy from their battery system to accidentally flow to the grid. The battery systems I've been looking at all ensure zero export to the grid from the battery system. Not hard to do, as the battery system has to measure the entire power coming in, or out, at the incoming feed to the property, anyway. It uses that to do its primary function of limiting import during peak tariff periods. The usual method seems to be fitting a current transformer around the incoming tails, in the same way as a PV diverter would, to detect the direction and magnitude of the current coming in or out of the incoming supply. In addition, a battery system needs to know the total power being generated by the PV system, so will normally use another current transformer clipped around the PV system AC feed.

That's rubbish. When I was doing sea trials prior to the acceptance into service of HMS Norfolk in 1989 I can assure you the deep fat fryers were alive and well in the galleys. The spread of the fire in HMS Sheffield was due to failings found in the fire and smoke control systems on the ship and there were a lot of injuries from flammable synthetic clothing that was used in uniforms at that time. There were also some early reports that suggested that the warhead hadn't detonated, when in reality it had. Somewhere I have a copy of the non-redacted version of the report, as I stayed in touch with my late friend's family for some time afterwards, and they obtained a copy. Because you wrote this: That implied exposed conductors.

It's always been the case the regulation shall not be applied retrospectively. For example, the regs now state that tails have to be 25mm², yet if I do an EICR on a house where the installation has older 16mm² tails that's not a cause for anything other than a C3 observation now. That changed a few years ago, as there used to be a category that specifically covered items that were compliant with an older edition of the regs. Forcing the use of C3 means having to explain to someone worried by it that it isn't really a problem, even though the definition of C3 is "improvement recommended but not required".

Yes, it was solely due to fire risk. The driver behind it was a series of CU fires, and the one that forced the change was a fire that started in a CU fitted under the stairs of a house, which trapped the occupants upstairs. Fitting CUs in the cupboard under the stairs is pretty commonplace. The regs don't say that the CU case needs to be metal, just fire resistant, although manufacturers have interpreted that as being metal. 30 odd years ago many CUs used to be metal cased. The Wylex board in our old house was metal, for example.

An exposed incoming live conductor is an immediate cause for reporting the installation as being unsafe. There is a mandatory requirement that there shall be no exposed live conductors, ever, and live in this context means both the line and neutral conductors, The incoming cable from the DNO is double insulated, as are all other exposed cables anywhere in an installation (or they should be, if correctly installed). The reason for this requirement is specifically to reduce the risk of accidental shock. If a digger goes through a cable there is probably going to be a bit of a bang. It matters not one jot whether there happens to be 1, 2 or 10 cables in the same spot, the outcome will be the same. What is the risk you believe to exist here? There's always a risk that an incomer can be hit by a digger. This risk is mitigated in several ways. Firstly, no one should dig without checking with a CAT, that's just common sense, and it would be gross stupidity to ignore doing this. Secondly, there is a requirement for marker warning tape to be laid above cables, to provide an early warning to someone digging that there's a cable, or cables, buried in that location. Finally, the design of cables for direct burial is such that if something conductive (like a digger bucket) does cut the cable, the first conductor(s) that it will contact is one at, or very near, local earth potential. This acts to protect the operator when the line conductor gets cut. Not at all sure why you want to try and make new safety rules up when the IET etc see no requirement for them. Do you happen to know something that the regulation writers don't? BTW, every warship I've ever worked on has had deep fat fryers in the galley. The risk from those is absolutely trivial compared to what's in the ship's bunkers and magazine. Arguably, the aluminium topsides on a modern warship are far more of a fire hazard than a couple of fryers in the galleys. As a footnote I lost three good friends in HMS Sheffield, a ship that I knew fairly well at the time.

I fitted a new isolator switch the other day that had really well-designed terminations. Not only did it have two socket head screws per terminal, but the design of the brass and copper terminal body was such that the tails were very securely held, with cable grips in the case far enough away from the terminals to get rid of the "sideways wobble loosening effect". The latter is my pet hate with cage clamps. You can do them up to the specified torque, then if you move the wire slightly you find that the thing has loosened a bit, especially with thick wires.

I've long been convinced that the major cause of overheating in CUs is loose or poorly designed terminals. The switch to fire resistant enclosures seems to be a secondary way of overcoming poor installation and design practices to me. If someone isn't competent enough to check that all terminations are tight and secure, then there seems a very good chance that they won't be competent enough to ensure all the fire seals are doing their job in the case.

Might be, if you have a problem. Pigeons seem to be the birds that cause the most problems, smaller birds roosting under the panels probably aren't a major issue. The cost isn't so much the netting, as the installation, as it usually needs scaffolding or at least a scaffold tower to get up there and work safely.

It'semi-rigid netting to close off the narrow gap around the edges of on-roof PV arrays, to stop birds from roosting/nesting under the panels. The reasons for stopping birds getting into this narrow gap are to prevent damage to the electrical connections under the panels, and to prevent old nests becoming a fire risk.

Usually they do, yes, as they will class this as a Temporary Building Supply (TBS) and a TBS installation has to be TT, as they won't allow the use of any incoming PE/PEN that's provided by the DNO. This usually means fitting a small CU with a suitable DP RCD plus one or two MCBs for the temporary supply. The TT installation also needs to be inspected and tested before use, to make sure it's safe. I chose to install a caravan hookup box, as this includes an RCBO together with a commando outlet as the temporary supply connection point.

To maximise the RHI the EPC definitely needs to be around the very bottom of the allowable level. I found that if you reduce the heating requirement, by having a decent level of insulation and good airtightness, the RHI reduces to the point where it doesn't make sense to have an ASHP installed by an MCS installer, as the "MCS premium" that's charged may well exceed the additional money received from the RHI. In our case the RHI payments were only going to be a bit over £80 a year for 7 years, no where near enough to cover the "MCS premium".

Because the hazard associated with cables that might somehow get some sort of short between them requires over-current protection, nothing to do with the risk of electric shock, really. If you look at the way concentric/split concentric cable is constructed you will see that the PEN, or PE and N, conductor(s) form a concentric protective layer around the well-insulated line conductor. The reason for this is so that anything conductive that may cut through the cable hits the conductor(s) that are at, or very near, earth potential before contacting the line conductor. RCD protection is for outlets, rather than cables. It's there to protect (by reducing the electric shock risk from touching an exposed conductive part) in the event of there being an excessive earth leakage, usually via a connected appliance. It's worth doing a bit of research to get a feel for why the various protective devices are used where they are, what each can and cannot do, and the specific risk each is intended to reduce. What common sense concern? You can safely run your hands along the outside of a double insulated cable carrying LV, after all. Where's the hazard? If something cuts through the DNO cable it matters not one jot that there may be an adjacent domestic cable, the risks and outcome will be the same. You might find it odd, but the issue re: using an all-RCBO CU has nothing to do with enhanced safety at all. A standard split board with two RCDs provides the same level of protection. The reason for using an all-RCBO board is simply the reduced nuisance factor, and easier fault finding, in that only the faulty circuit will trip in the event of an earth leakage fault, not half the board. FWIW, our all-RCBO board didn't cost close to £300, either.

The MSDS doesn't list everything, only the hazardous stuff, and IIRC Kurust uses tannic acid, rather than phosphoric acid, as the ferric oxide converter. Both tannic acid and phosphoric acid are used in food (phosphoric acid is what give Coke much of its flavour, for example), so they don't normally need to be listed as hazardous.

No it doesn't, it's lead-free. The MSDS is here: https://www.hammerite.co.uk/files/2017/02/HM_GB_EN_KURUST.pdf

Phosphoric acid works by converting red ferric oxide (rust) into black ferric phosphate. Nothing to do with lead, the black comes from the natural colour of ferric phosphate. Ferric phosphate is a pretty good primer base on steel, as it will provide a degree of further corrosion protection, will readily absorb oil to provide further corrosion protection for "blacked" steel parts and bonds well to further paint coatings. In this case, I'd be inclined to just wash out all the bits of rusty swarf and then just wipe away any staining if you can. Phosphoric acid isn't a very strong acid, but if you can avoid using it I would. If you do get phosphoric acid on particles of swarf it will probably make them more corrosion resistant for a time, but they will start to rust again before long.

Not sure where your electrician has made that up from, but I've just leafed through the blue book and there's nothing in the regs stating that. There's no requirement for separation of double insulated power cables, and even if there was 400mm is completely OTT. Get you bloke to read his copy of the blue book and confirm to you which section he thinks specifies this, as I can't find it anywhere. Electrical separation and the requirements for basic protection are in sections 413 and 416 respectively. FWIW, a 1A fuse is of no benefit to any living creature, either. 1A is several times more current than is needed to kill you. Anyway, fuses and over-current circuit breakers are not there to protect from electric shock, they are there to prevent cables over heating and causing fires.

I doubt that ordinary UFH heating wire would survive the concrete pour, TBH. I loose laid electric UFH wire under the tiles in our bathroom at the old house, and It's not very tough stuff.

They are both double insulated LV power cables, and there's no specified separation distance requirement. Also, both circuits are protected, as the incomer will be fused upstream, albeit with something like a 400 A to 800 A fuse.

How on earth can I have been "brainwashed", and who exactly was responsible for doing this? I was prohibited from membership of, or supporting, any political party for 35 years. I've remained staunchly apolitical. IIRC I'm still prohibited from any political activity until later this year, 10 years after my retirement date, although I've no intention of ever being associated with any political party, anyway. Just like anyone else, I have opinions, largely based on experience of working within government for most of my working life, but frankly I don't have much time for politicians of any flavour. In my view they are all pretty much as self-centred and bad as each other. I've only known one politician in my life who was a decent, caring, human being, who genuinely cared about his constituents, and that was David Penhaligon.

The reality is that there were more council houses sold during the 13 years of the Blair/Brown government than there were under Thatcher. Much as I detest Thatcher, it's very clear that the following Labour government under Blair, in particular, endorsed some of her policies, including the sale of council housing stock and, more importantly, the fiscal controls that limited the building of more social housing. Labour, under Blair, continued to support the idea that social housing should be provided by housing associations, rather than government.

Just measured a double gang one, and it's about 69mm high, 45mm deep and 130mm wide internally. I've checked the part number and it's an MK K2062 flange box, like this: https://www.mkelectric.com/en-gb/Products/WD/BoxesandAncillaryProducts/boxes/mouldedboxes/flangeboxes45mm/Pages/K2062WHI.aspx I have a box with at least a dozen of them here, all individually boxed. I have a feeling there may be a few single gang ones somewhere, too, but so far I've not found them.

I have a box of deep plastic back boxes that have a flange around the front that are just sitting gathering dust. Your welcome to some for free if they may help. I can't remember where they came from, but they are pretty solid things. I'll try and dig one out and take a photo.

One potential problem I can see is that the inside face of the building now looks like a very well shielded Faraday cage. These switches use RF, so they ideally need to be housed in an RF transparent housing. I suspect that the range will be reduced if they are mounted in a standard metal back box that's fitted to that very well RF shielded room.

There's also a potential problem with using lead above a window, as the glass will end up being stained by the lead salts that wash out over time. As a general rule it's best to try and arrange things so that there isn't much possibility of water running off lead flashing on to glass.

The version we used fits above the battens and under and over the edge of the slates, with a drainage channel to ensure any rain that does flow over the internal edge flows down to the gutter. Being very thin aluminium, it is fairly easy to fit, although it has to be opened up and sprung over the edge of the slates.