Jeremy Harris

Ours are the same, @joe90, and I'm going to change the elements out (or at least the one in our ensuite) for a thermostatic one, I think. I went for the lowest power element I could find, but it still gets too hot for comfort. I have both of them on a time switch, so could play around with the timing settings to try and reduce the temperature, switching the rails on and off every 15 mins during the "on" time.

Just been checking wholesale prices, to get a feel for the sort of difference that removing the tariff is likely to have. Chinese manufacturers seem to be about 1.5p/W cheaper, at the most, than other manufacturers. Current wholesale module prices seem to be running at around 28 to 30p/W, so we might see a maximum wholesale panel price drop now the tariff is removed of as much as 5%, perhaps. That may well not result in a retail price drop that's as great as this, though, as my guess is that retailers have been working on pretty slim margins for a while now, so they may well take this opportunity to improve their margins, rather than match the wholesale price drop. It's going to take around 8 weeks for the first Chinese panels to arrive in the UK, at a guess, so we won't know the true impact on prices for some time, probably not until well into the new year when there has been sufficient additional supply to have a significant impact on the UK retail market. First places to watch for low prices are likely to be those retailers that had a tradition of importing panels direct from China in the past, and who have maintained a business selling other Chinese made products directly into the UK market in the meantime. I can think of three or four companies that may well be ones to watch, but first off the mark are bound to be all the drop-shippers on Ebay and the like, who will almost certainly get in first with lower prices, as their supply chain is already in place and their UK overheads are already very low. The downside there is going to be whether the quality is OK. No reason to suspect it won't be, but I think we can expect to see a lot of Chinese made panels in the drop-shippers outlets that don't carry any real form of approval. Whether that matters or not for something as relatively simple as a PV panel is debatable, as long as the panel cabling and connectors are checked and found to be OK.

It might happen, but I'd not hold my breath. The anti-dumping tariff did virtually nothing in practice, and I strongly suspect that the USA imposing punitive tariffs won't have much impact either. What seemed to happen is that manufacture (or probably more accurately, assembly) shifted from mainland China to other areas in South East Asia, and my guess is that Trump won't go as far as to impose punitive tariffs across the whole of that region.

Just to throw a note of caution in here, having looked at the relative prices of panels actually made in China, that attract the anti-dumping tariff that's being scrapped, vs the price of the same panels made by the same companies at their offshore factories (outside China), and by panels made by non-Chinese manufacturers there isn't that big a difference. When the EU introduced the anti-dumping tariff, Chinese panel manufacturers got around it by moving assembly outside China, so that the panels didn't then attract the EU tariff. This was slightly more expensive, but it allowed them to sell into the EU without the punitive duty. However, since then manufacturing costs have increased in China, and despite the high volume of production, panels supplied direct from China without the burden of the EU tariff aren't going to be massively lower in price. I reckon at the very most the saving might be around 2 to 3% to the end user, worth having, perhaps, but nothing like the headline-grabbing anti-dumping tariff rate of 30%. Part of the reason that the EU are dropping the anti-dumping tariff is because it has been ineffectual, so I'm not convinced we'll see a big drop in prices at all.

For me it's the way it's a fair bit simpler to get all the critical detailing right so as to remove or reduce thermal bridging with a structural timber frame. A well-designed timber frame built on an insulated slab solves one of the more awkward thermal bridging problems, the wall to floor junction, pretty simply. Systems like ICF and Durisol can give a similar advantage, and can also go up pretty quickly, too.

But they aren't Quinetic ones. The Quinetic switches are radio remote control ones, that use the energy from pushing the switch to generate the power for the transmitter, so don't need batteries. One glitch with the standard "on/off" Quinetic switches is that if there's a power failure they can end up the wrong way around, as if a light was on when the power failed, when the power comes back on the light will default to off, but the switch will still be in the on position. The way around this is to use the dimming switches with a standard receivers, as they are just push switches, they don't have an on or off position. Push one for on, push again for off.

Either here, or perhaps on it's predecessor Ebuild, I'm pretty sure we did a bit of a joke calculation of how many dogs/cats were needed to keep a house warm... Our open weekend was late spring, so well outside the heating season, which didn't help.

That's really weird, as a loose earth can't (or shouldn't) be able to cause an imbalance in the L&N. I'm not even sure the room stats use the earth, do they? It's only there for the cable protection I thought - at least it is for the room stats in our place - the earth at the stat end is just "parked" and doesn't make an active connection. What could cause either an earth leak, or, more likely, perhaps, a voltage/current phase error spike, that would cause the nuisance trip? Inductive loads can do it, but there's nothing there that's a big enough inductive load to do it, I'd have thought. Maybe the contactors were causing some sort of induced spike in the stat cable, and connecting the earth up the cable was enough to reduce it? Sounds a bit implausible, but stranger things have happened.

Very true @Ed Davies. Sometimes trying to simplify stuff as an attempt at clarity leads to technical inaccuracy, and I didn't want to get bogged down in the "power is proportional to the square of velocity and energy is proportional to the cube of velocity" stuff, for fear of the post being too long and too technical for some!

The short answer is that anyone can fit up to 16 A per phase of microgeneration, without the consent of the DNO. Don't get confused by power - it doesn't, strictly speaking, apply, as the G83/2 limit is 16 A per phase and the power can vary a great deal depending on the supply voltage at any time. For example, the official UK supply voltage is 230 VAC +10%, -6%. It's a fudge, as the true UK supply voltage is the same as it was before unification with the EU, about 240 VAC, hence the offset tolerance. 16 A at 230 VAC = 3.68 kW, hence that figure being quoted. But, at 240 VAC (which is a more realistic figure) the power will be 16 x 240 = 3.84 kW. At the upper limit of the UK supply voltage, 253 VAC, the G83/2 power limit increases to 16 x 253 = 4.048 kW. In the sloppy parlance used by PV installers, a G83/2 compliant system is very often called a 4 kW system, and as long as the inverter is set to limit to 16 A per phase (which just means selecting the G83/2 mode on it during installation) then you will be compliant if you have 16 off 250 W nominal panels, as the vast majority of UK G83/2 systems have.

Another thing I've found out the hard way is that orange juice attacks travertine floors (travertine being calcite, a polymorph of CaCO3, calcium carbonate, or limestone). I have put three coats of silicone sealant on our flooring, but there is one spot where a drip of orange juice fell on it that has a rough depression where the citric acid has dissolved the surface. I've found that travertine chips and damage like this can be repaired very well with a mix of powdered travertine and epoxy resin as a filler. I created some travertine dust with the belt sander, painted some neat epoxy resin into the damaged area, then applied a very stiff mix of travertine dust and resin to it. When the epoxy has partially cured, the surface can be levelled up with a Stanley knife blade, and when the epoxy is fully cured it can be polished up with a scotchbrite pad. Not sure it the same principle would work with limestone or not, but I know that some famous stalactites (which are also calcite) in a cave in South Wales ( Ogof Ffynnon Ddu) were repaired with epoxy back in the 1980s and now you can't see the repair, as fresh calcite has formed over the glued joints.

You can mount a Savonius device like this horizontally, or at an angle and it will still work OK. The Betz Law limit for a device of this type is a lot lower than the ~59% maximum efficiency for a theoretically "perfect" device for extracting power from the wind. It's roughly half the Betz limit, so a maximum theoretical mechanical efficiency of just under 30%, and an estimated maximum practical efficiency (if developed to the same level as variable pitch, variable blade twist, axial turbines) of less than 25%.

Just wanted to say thanks, in general, for the idea of a heat transfer fan. It's got me thinking that such a fan fitted to the water-cooled heat exchanger that I've already bought, and arranged to recirculate air and chill it around our first floor, may be far more effective in terms of providing first floor cooling, to augment the slab cooling we already have. In effect, I could make a semi-hidden fan coil unit, with the fan and cooler fitted in our first floor services room (which is lined with acoustic foam to absorb noise anyway) and a duct running in the void over the second bathroom ceiling and coming out high up in the entrance hall atrium. Recirculating air has to be more effective at cooling the house than drawing in warmer outside air and cooling it.

Danger money indeed. When I was young (and skint) a friend who worked at Penryn Granite ( a quarry that's main product was crushed granite roadstone) asked if I wanted to work there for a bank holiday weekend and earn £200 cash in hand, no questions asked. The job was emptying out, cleaning and refitting several hundred bag filters from the dust extraction plant. Each felt filter bag was around 6ft long and 8" in diameter and virtually full of fine dust, high in silicates, extracted from the crushing plant. We did it, wearing respirators they gave us, but ended up completely white with very fine silicate dust at the end of each day, and were blown clean with an air lance (around 2" in diameter) driven by a massive Broomwade compressor. Around our faces we had a mess of silicate mud, from where sweat had mixed with the silicate dust. When we got paid on the Sunday night, we were all asked to give false names and addresses in a ledger, so that we would be untraceable as far as the company was concerned. It was only later, after we'd all developed a bad cough for a week or so afterwards, that I discovered the risks from silicate dust and the reason we'd been paid so much to clean the filters. Thankfully I don't seem to have any lasting effects, as I've had dozens of regular chest X rays over the years and all have been clear, and I don't think that silicosis has the same sort of delayed effect that asbestosis does.

There are two main types of vertical axis wind turbines, and they both have different upper limits. The Dyson ones, like the "cut in half oil barrel" ones, are variations on the Savonius design (see here: https://en.wikipedia.org/wiki/Savonius_wind_turbine ) that use drag as the motive force and have the advantage of simplicity, they cannot easily over-speed in high winds, they don't need to point into the wind and they can still operate reasonably well in "dirty air" (i.e. air that's pretty turbulent, such as in urban areas). The disadvantages are significant, though. Because they can only ever deliver power equivalent to the differential lift and drag of the side facing the wind, their overall efficiency will be well below the Betz Law limit***. The other disadvantage is that their main bearing takes a very high bending and shear load when operating, or just held stationary, in very high winds - a much greater load than an equivalent power axial turbine. The other type of vertical axis turbine uses lift as the primary means of extracting power, like the Darrieus rotor (see here: https://en.wikipedia.org/wiki/Darrieus_wind_turbine ) and can be a fair bit more efficient - in theory they could be as efficient as axial blade wind turbines and, like them, operate at close to the Betz Law limit***, which so far has seen wind turbines that run at up to about 48% mechanical efficiency (there are electrical losses and transmission and conversion losses that reduce that a bit). In practice, there hasn't been as much investment into developing Darrieus designs, for a host of reasons, including the complexity of some of the rotating components, the challenges of servicing them, and just the fact that an immense amount of money has already been invested in developing axial blade wind turbines, so there's no real incentive to invest in Darrieus type machines. The Dyson device seems to be fairly and squarely in the "chocolate teapot" category as far as I can see. Urban wind turbines have a host of problems not associated with the design, such as noise, vibration, finding safe and secure mounting locations for them on or around buildings as well as the inevitable return on investment conundrum. A Savonius rotor type design, even if highly optimised, as I'm sure Dyson has done, is still going to be a very low efficiency device, and that, combined with the much lower overall wind speeds in urban areas (buildings create drag which slows down the low level wind speed a lot), means that the net output for any given free air wind speed is likely to be too low to generate a worthwhile amount of power. I wish him well, but feel that this is another idea that won't take off commercially. *** The Betz Law limit is an interesting concept that can be a bit hard to get your head around at first. In essence, Betz started from the standpoint that any wind turbine device could never extract all of the available power in the wind flowing through it, because if it did, there would be still air behind the turbine device. The problem with that is, if the air is still behind the wind turbine device, then how can there be air flowing through it to generate power? There are some who have argued that the formula Betz came up with to describe the maximum mechanical power extraction efficiency of any wind turbine device may not be wholly valid, and I can think of a few ways in which the limit he proposed might possibly be broken, as curiosities only, but for all intents and purposes the Betz Law limit works well as a practical limit on device efficiency. In simple terms, this limit means that every the very best wind turbine cannot extract more than about 59% of the available power in any free stream of wind. For those that want to do the sums, Betz Law is described in more detail here: https://en.wikipedia.org/wiki/Betz's_law

We get pretty much the same - often the worst case solar gain for us is late autumn to early spring, when the sun can penetrate deeper into the house. We also have exactly the same issue with visitors. A while ago we held an open weekend, showing groups of around half a dozen people around every couple of hours. It got so I could pretty much predict when the MVHR would switch to cooling more (it's slightly audible on full boost daytime cooling) and that would be around 10 to 15 minutes after the visitors arrived. People are surprisingly effective at warming up the air in the house.

Is it? Really? Off the top of my head I can think of quite a few hands-on self-builders (excluding myself) that are regular contributors on here. Ones that stand out as having made a tremendous effort on their own, with little or no local help, are builds like @Crofters, on Skye, the brilliant build in the Carbeth community by @Tennentslager, the lodge built by @iSelfBuild, the lovely home that @Declan52 has built for an astonishingly low budget, with his own hands from the ground up, the trials and tribulations that led to @ProDave getting a digger and doing most of the build of his home himself, much the same with @recoveringacademic, who, like me and you, started with near-zero practical knowledge of the construction industry, as well as many more that you could find if you looked around. Sure there are some with construction industry experience self building here too, and doing a lot of the work themselves, people like @joe90 and @Russell griffiths spring to mind, but there are others. Have a good read through the trials and tribulations of some of the builds on here, and read the responses from others to those trials and tribulations, then see if that still, on balance, matches your assertion that we, as a large group of self-builders and renovators are generally "quite hostile to the genuine aspiring hands-on self builder". My own view is that we are, collectively, quite the opposite, and if anything we probably tend to overwhelm some aspiring self-builders with well-intentioned advice initially. The key to how things go from there is how individuals respond to that advice. Those that take what they need from it, and get on and do a bit then thank people and come back for a bit more advice are very much welcomed.

Worth checking, but extract filters don't usually get anywhere near as dirty. You should be able to check whether you have an intake filter quite easily, as they are user-serviceable components, and a dirty one does tend to look obviously dirty, as the photo above shows!

That may well be the case, but that's only because no one thought to post about hand assisting a powered on mixer before. Whether that's because no one had thought to do such a thing, or whether that was because anyone thinking of doing it either hadn't posted here, or had just read the instructions for their mixer and found that it was an unsafe practice, or whether it's because some have already gained experience with mixers and had it drummed into them (no pun intended) that it was unsafe none of us can ever know, That's an assumption, one that happens to be false, for a few reasons. Firstly, I have no particular religious conviction, so by definition cannot be engaged in "jihad" with anyone. Secondly, if I was of a particular religious conviction it would not be appropriate, or within the terms and conditions of this forum, to try to impose my beliefs on another member. Thirdly, I have absolutely no feeling one way or other about you at a personal level. Finally, I will state again that there is no such thing as the "Small Claims Court", there is just the Small Claims track in the County Court, a simplified method of making a low value civil legal claim for a limited range of circumstances, that avoids the need and expense of instructing a barrister (via a solicitor), or instructing a solicitor directly who has higher rights of audience, to represent a claimant in a Crown Court or other higher court, as litigants in person are generally accepted more freely, without restriction, as such cases are not heard in the formal setting of the higher court. If you feel that I've tried to correct too many errors or assumptions in your posts, then that is because I felt that there were errors or assumptions there that needed to be corrected, it was not anything to do with you personally at all.

Good points, but I did used to teach apprentice electricians, so have at least got those qualifications and experience, plus was certificated at the time, as it was a requirement that I had to be in order to be a part time college lecturer. I'm aware of the gulf between "paper knowledge" and "practical knowledge", which was part of the prompt for this thread. Insurance is certainly something I'd missed, and probably stops this endeavour in it's tracks, so thanks for that reminder. I've just had my tester calibrated, so that's OK. As in the post above, I'd not ask another scheme member to use my schedule of tests and measurements, as it's an unreasonable thing to ask and it just wouldn't be fair on them to ask the question. I think my main point here is that Part P has nothing to do with being considered a competent person to undertake an EICR, as it's not a Part P notifiable job, AFAICS. I think the main cock-up with Part P was making it a building regulation, so separating it out from the normal competency requirements for electrical work. I'm sure there are still electricians around who don't have a Part P accreditation and who have the same qualifications and certification that I hold, dating back to the 15th Ed. The onus is on them to stay competent, but as long as they don't undertake Part P work they can carry on doing any other electrical installation work, AFAICS.

Yes, chemically the same as limescale CaCO3, so any cleaning product for limescale will attack it, as will any acid, like the very weak acidity of urine (urine is usually has a pH of something like 6 to 7 in healthy people, IIRC, so varies from being slightly acidic to neutral).

I agree, @jack, I just have a very strong DIY tendency and have been wound up a bit by the surveyor (who was quite open to me about the wiring as he was doing the survey). @Stones, Re: the socket in the cupboard, it's not there - I took it out before the surveyor came around, just to be on the safe side, and there's no indication it's ever been there now. I needn't have bothered as he didn't look in that cupboard, anyway!

How on earth can stating the standard way that mixers have been used for donkey's years be condescending to anyone? I'm sorry, but I'm not likely to thank you for making the potentially dangerous suggestion that anyone should "use muscle power to help the first 10 degrees of rotation". To even think that was a reasonable thing to do shows a disregard for the obvious risks. The key here is the way in which information is conveyed, and whether or not a new member of this forum, with little or no knowledge, might assume from the author's writing style that he or she is knowledgeable and so their content should be trusted as being accurate and safe. I'm afraid many of your posts do come across as if you have become an overnight expert in several areas, when just a short time ago, in May of this year, you appeared to be disparaging about those of us here with years, or decades, of experience and admitted that you knew little about trades, when you wrote this: Apart from the above being factually incorrect, in that I cannot find a single reference anywhere in any of the content on this forum that states, or even implies, that "Early encounters with the good denizens of the BuildHub forum tarred me as a hopelessly naive computer programmer fit for little more than making tea onsite". All I can see are people offering free help and advice, coupled with responses from you which seem a touch arrogant and supercilious. This is a generally very friendly place, and a lot of that relies on give and take, plus members having a bit of humility when they make an error and correct it. It's not acceptable, in my view, to express arrogance, as in "These points are now clearly stated in the public domain because of my follow ups. You should be thanking me.", especially when the aspect in question, never hand assisting a powered mixer, has been in the public domain as plain safety common sense since I was a small boy. I've made enough errors here, and tried to correct them whenever I've found them or they have been pointed out to me, to have learned that it's generally more acceptable when trying to make a point to be slightly less assertive that I would be inclined to be normally. We all have to accept that there will always be members that hold contrary views to our own, and they are entitled to do so. The problem arises when contrary views are stated assertively and promote an activity that has long been known to be dangerous, and has caused a number of serious injuries on building sites over the years. As a forum, we should collectively try to make sure that we don't promote anything in an authoritative-sounding post that is potentially unsafe or unlawful.

Yes, but to be honest he's young, competent and dead honest, and I know he'd not want to work the system like that, but would want to check for himself, even if he does trust me. If push comes to shove and it really does look like it's going to be a problem, then I'll just buy a new CU and get him to wire and test it. I'm pretty sure I'd get "mates rates", so at most the whole job isn't likely to cost me more than £150. It may well be worth that just to stop all this faffing about.

It's the same situation we were in. The pole we wanted removed was an SSE pole but with an Openreach cable sharing it. Having got SSE to shift their cable (after months of delay) I struggled to get Openreach to move theirs. What's supposed to happen is that when SSE declare they are going to move a shared use pole, they are supposed to automatically send a request to Openreach (at Liverpool, IIRC) but in our case this didn't happen. Without the number of that request (I think it's called an ONR number) the local Openreach people can't shift their cable off the pole. The advice I had was to have all the new Openreach underground cables in place (they had been for weeks - we laid the ducts for them and pulled their cables through, leaving them coiled up at the base of the poles) and then, early one morning, "accidentally" snag the cable with the digger and immediately ring the Openreach hotline. We had an Openreach team there within about half an hour, they took one look at what had happened, saw the coils of cable waiting to be connected and said "This is a (name of local Openreach engineer) job, isn't it?" Worked a treat, though, except for annoying the lady up the road who had one of those emergency alarms, that started warning her that it wasn't connected, so she walked down the lane and laid into the Openreach guys until I calmed her down, saying it was just and accident and her line would be back up in a few minutes.