I disagree, solid can miss the screw altogether, with stranded something will grab.

"Not working at all" is a better outcome than "Being partially connected, yet not having the full wire size connected." The first is easy to troubleshoot. The second works, until it overheats the few strands that are connected and causes problems.

Time is a limited resource.

I agree, that's why I do it properly the first time, instead of constantly having to go back and check to see if I screwed up.

Nonsense. If you have a 5kW heater and only 2.5kW is needed to keep the room warm, it will cycle on/off at 50% duty cycle.

Fine, and entirely irrelevant. The wiring still has to handle the full rated draw, safely, for extended periods of time.

The general design of wiring and circuit protection, per what I'm familiar with, is that any wire must be rated to handle the full current the upstream protection device can provide - so if you have a 20A circuit breaker, the wiring had better be able to handle 20A indefinitely. The continuous load derating factors in here too.

All you need is "This is 20A wire. Deduct 20% if under insulation, deduct x% for this, y% for that."

As clearly stated in the various charts and correction factors you refuse to consider. "12AWG Copper 90C XHHW-2" is sufficient to answer all those questions. You're just insisting on your right to not have to bother.

What percentage of people die in a building fire? Probably a billion times less than a car accident or cancer. You sound like the UK government, concentrating on the wrong things.

US fire deaths are about 3800/yr, automotive fatalities are around 38,000/yr, give or take on both numbers. So, 10x difference, a couple orders of magnitude less than your guess.

And a good reason that the fire deaths are fairly low is things like the NEC, that dictates wiring standards in a fairly conservative manner, vs "Do whatever you want and hope it doesn't catch fire."

If the problem is that your wiring is undersized for the job and the bulk of the wire is getting hot, this will work. If the problem, as you seem to imply, is your connections getting hot, you've got a bad crimp job, an improper connector for the job, or the wrong sized connector for your wire gauge (connectors have a rating for what wire gauges they're designed to work with, though there I go, nerding out about complex arcane specifications like "8-14 AWG" and such). You can probably cobble around it with more wire and connectors, but if you're not fixing the root problem, it's a rather cost-inefficient way of solving the issue (throwing wire wire at a connection termination problem).

What sort of "hell of a lot cheaper" prices are you seeing on it where you obtain the stuff? I know it used to be the case, but I just went poking around the site I usually order a lot of my wiring from, and 8AWG copper and 6AWG aluminum are almost the same price - 6AWG THHN-2 Al is $0.52/ft, 8AWG copper is $0.56/ft. I can't even find smaller aluminum wire anymore. Both of these are good for a 50A circuit under mostly standard conditions.

It's marginally cheaper, and if it's a "run it once and be done" sort of situation, the differences don't really matter.

I tend to use the stranded stuff, though - as you note, it's a bit easier to work with. I don't mind working with solid wire, though. The house is wired up with 12AWG solid copper, and it's fine.

I'm pretty sure I used stranded for the solar runs. Solid is a bit easier to work with for some terminations, though.

Then I have zero idea why you object to doing something like "looking up some wire ampacity charts and figuring out the proper wire gauge for your actual needs." Design it right from the start, and you don't have to go around "touching wire to see if it's too hot."

I was asking if your wire which you claim is 8A rated was rated assuming continuous or intermittent loads.

Heating is by definition a continuous load, for any hard wired heaters.

And also generally useless in designing anything more complicated than an extension cord. Wire gauge, insulation temperature rating, and the rest of the factors flow into some pretty simple charts and calculation factors based on what you want to do - if you've got more wires in a conduit carrying current, they're each derated somewhat because of total conduit heat dissipation issues, if they're being used in a high temperature environment, they derate as there's less overhead between ambient and the insulation rating temperature, etc.

You seem oddly resistant to the concept that electrical faults are a major cause of building fires that very much do kill people. Cracked insulation from lower than designed temperatures is a genuine hazard - and even if it doesn't arc, it's still allowing water and other things in to corrode sections of wire that are impossible to inspect, because they're in the center of segments of conduit, walls, etc.

Won't they all go under 0C? People put wires outside all the time. My mother keeps her mower and extension cords in the garage and it gets to -10C there. They just go a bit stiffer.

Insulation not rated for the lower temperatures will likely get brittle. Norway and Finland often get -40C. When in the forces I saw insulation intended for warmer climes break. Some might be fine but just not been tested for lower temps but some not rated will almost certainly be dangerous.

It's stranded, I'm not counting those, why would that matter, I just twisted them up hard and measured the total.

This single statement clearly demonstrates your total lack of understanding of cable construction. Twisting cables in the manner you describe does not totally remove the packing space between the cores so the actual CSA of the metal is always less than that which you've guessed at.

You are lazy, arrogant and stupid - clearly demonstrated by your disabling the "not wearing your seat belt" alarm when driving - don't forget it's an offence which costs you money when caught. Boasting about such acts does eventually end you up in court.

I hope you also undertook the oh-so-bring task of counting the number of cores as well. (It's not too bad when there are only 7 cores, but did I get to 37 or 39 before Fred shoved a cuppa under ones nose?)

All compliant (stranded) with current standards cable, above about 1mm^2, is required to have the conductor cross section, and insulation class (which may include the type of insulation), printed on the cable at regular intervals. Thus the cable you are suing does not comply with current regulations, or is rather old, and may, or may not, be compliant. There's a lot of non-complaint cable coming in from the far east (India & China being the main sources).

...and then there are "Arctic grade" cables, which extend the range down to -20C (ore even lower!), which is quite useful if you want to use the cable outside when normal people want to stay inside hugging the heaters....

Most of us could reasonably claim to be short of money, but most of us do use the "right stuff".

It's cheaper for good reasons - not the least of which being that without the appropriate markings it is automatically non-compliant with current standards.

What defines someone as a narcissist?
Overview. Narcissistic personality disorder is a mental health condition in which people have an unreasonably high sense of their own importance. They need and seek too much attention and want people to admire them. People with this disorder may lack the ability to understand or care about the feelings of others.

GPU feeds, 12.6V, 4AWG ring. More the connections get hot.

The connections shouldn't be getting that hot - usually that indicates a poor crimp job, though if you're using aluminum wire (aluminium, however you want to spell it, same material - Al, of some reasonable alloy), you've likely got some oxidation issues going on at the connection. Oxidized copper conducts. Oxidized aluminum doesn't, and a high resistance connection makes for a lot of heat, and tends to make the oxidation issues worse until something stops working - or, more often than it ought, catches fire (I've seen research that the number of "thermally faulty" outlets in a fleet of houses with aluminum wiring vs copper is about 50x higher for aluminum - and that's before you get into the long term behavior of the wire, which is "less agreeable" in terms of work hardening, thermal hardening, etc).

There are reasonable places to use aluminum wire, but I'd argue (as a serious DIY sort) that aluminum wiring is best left to people doing it professionally, because it really helps to have things like explosively welded lugs on the end of large gauge aluminum wiring (they literally weld the lugs to the wire with explosives, and there's no way for it to oxidize at the joint as the metals are firmly bonded). If you try to treat it like copper wire, you'll have a genuinely bad time of it eventually, because it's not well behaved like copper is - it work hardens more easily, it's more prone to stress fractures and cracks, and you pretty much can't use it in screw terminals for the long term, because the thermal expansion and oxidation behavior will eventually make your screw terminals glow with any serious power through them.

Or just use regular stranded cable and skip the fine stranded for interconnects. I've got a range of good crimping tools, to include a DC wire crimper that will do up through 0000AWG or maybe a bit larger.

Wiring up high loads with "cables laying around," where you don't know the wire gauge, haven't calculated loads, etc, is the sort of "casually sloppy with high power things" I'm criticizing you for

in the sense of claiming that you don't have enough electrical background to be able to have any interesting conversations about your shortcuts. At least in your posts here, you come across as having a "Eh, whatever, it works for now..." attitude towards wiring.

Your wiring should (if it's halfway competent wiring) be labeled with wire gauge, either in AWG, or in cross sectional area, and it should also be labeled with the insulation temperature rating.

The lowest temperature wiring insulation in common use is 60C/140F rated

"Adding more when there's a problem" isn't a replacement for a properly designed system, as by the time you notice it's hot, you've likely already gotten things hot enough to start causing thermal damage and further oxidation.

8A continuous, or intermittent?

Typically, in electrical rating for wiring, there's a different rating for "continuous" (>3 hour) loads vs intermittent loads, and at least in the US National Electric Code, an 80% derating applies for continuous loads. So 90C 12AWG is rated for 30A, but for continuous loads, it's only suitable to 24A. This handles thermal mass and inertia in wiring - running a blender for 5 minutes is going to heat up wiring less than a heater, solar backfeed, EV charger, hot tub heater, etc.

This is why wire also generally isn't rated for "amps"

But at least there's an ocean between your place and mine.

Ah, a BT engineer told me this was why my 1979 phone line was rubbish. He said something about them coming loose. But for the price I'll stick to aluminium!

See Terry Pratchett.

The reason that the rich were so rich, Vimes reasoned, was because they managed to spend less money,” wrote Pratchett. “Take boots, for example. He earned thirty-eight dollars a month plus allowances. A really good pair of leather boots cost fifty dollars. But an affordable pair of boots, which were sort of okay for a season or two and then leaked like hell when the cardboard gave out, cost about ten dollars. Those were the kind of boots Vimes always bought, and wore until the soles were so thin that he could tell where he was in Ankh-Morpork on a foggy night by the feel of the cobbles. But the thing was that good boots lasted for years and years. A man who could afford fifty dollars had a pair of boots that’d still be keeping his feet dry in ten years’ time, while a poor man who could only afford cheap boots would have spent a hundred dollars on boots in the same time and would still have wet feet.

Peter. Do some quick sums to check the rating of the cable needed for you 5kw resistive heaters. Even doubled "8A" cable is way under sized:
5000/240 = 20.83A (assuming you actually getting 240v in your location) - so you need to at least use three cables, single in air;

but even that is marginal if the mains voltage droops to say 220v (which is still within spec of UK supply).

Oxidation of conductors is more often associated with environmental conditions than temperature of conductor (unless the conductor is REALLY hot - over say 200C). The most common to fail first at elevated temperatures is the insulation. The mode of failure depends on the insulation material and the conductor metal will delaminate from the conductor, or go "brown and crispy", or go soft and floppy.

Evil screw connectors - aluminium (miss-spelled by those led by the Americans for spelling as aluminum) conductors take very badly to being compressed by most screw terminals rapidly becoming work-hardened and so fracture. (Yet another good reason for not using aluminium conductors in domestic installations.)

And I do use decent thicknesses of cable for high voltages too, so the wire doesn't wear out. They tend to oxidise if they're warm all the time, then they end up not conducting at all.

How "warm" are you running your wires if they're oxidizing on you? And are you running improperly terminated aluminum? Copper doesn't do that at any sort of sane temperatures (I typically use 90C rated wire, though occasionally have to derate for 60C rated breakers/switches/etc).

(in the land of "Doing it properly," I've yet to use aluminum wire for anything, and never intend to - the slight extra cost for copper is totally worth the tradeoffs of "Isn't evil in screw terminals" like aluminum is)

Right. I'd forgotten your electrical knowledge was far enough off in the weeds that we can't actually have a reasonable discussion about what "shortcuts" are reasonable.

They are more important than you?

Yes. Absolutely. Without question. I'd rather not kill them to save a few dollars on doing a job properly, especially when I'm saving so much by doing the work myself.

I don't find "doing it properly" to be a particularly painful process, either.

In the context of electrical wiring, this means NEC wire gauge or larger (I discovered that past-self was clever enough to use the full rated wire gauge for a run from my charge controller to my batteries, even though I had a smaller breaker in place at the time, meaning that when I needed to upgrade the breaker to better match my increased production, I didn't have to replace the wire run), proper junction bars as needed, etc. And I have a thermal imager to find hot spots - it's quite the fun little toy that gets used often enough to verify things are running as expected.

And we go overboard with safety. Obvious safety is common sense and doesn't need legislation.

The history of industrial accidents, aviation accidents, and quite a few other things disagrees.

Quite a few things that matter to "not kill people" are not, in fact, "common sense" - or they'd have been done.

Further, there's a difference (to my mind, at least...) between "doing something stupid that kills yourself" and "doing something stupid that kills other people."

How pathetic. I use two hands and it won't kick right up to my face. If it did, it would cut out before it got that far. And kicking up is damn obvious for anyone who understands the most basic law of physics, equal and opposite reactions. If you don't understand it, I don't want you to live. Imagine a world where all the stupid folk had been killed off.

Man, you're an ass at times. I assume you do that on purpose. But it's far from the first time I've encountered that mentality.

I typically wear a helmet and hearing protection

when using a chainsaw, and as I have a perfectly good set of chainsaw chaps, I wear those often enough too. I know people who've gone through 6-8 months of rather extensive pain, suffering, and loss of employment from having a circular saw go through their leg on the job.

It's the same reason I wear competent motorcycle gear when riding.

Don't get me wrong. I fully support your right to use a chainsaw with zero protection at all. I fully support people riding motorcycles in shorts, a t-shirt, and flip flops. I just happen to think quite a few things like that are stupid. And I support my right to call people out for their overt stupidity.

I mean seriously, warnings on chainsaws not to stop them with your genitals?!

Where do you buy your chainsaws from? Neither of mine came with any such warnings!

And health and safety measures are only common sense for someone who fully understands what is involved. A chainsaw for example can under certain circumstances kick up which is why I always wear a safety helmet while using mine

Never understood why people need to be warm to take a bath. Cold temperatures are actually very good for your health.

I've no problem with it personally. I'll not fault my wife for raising the temperature up a bit with a 1 or 2 year old for bath time.

As for safety, that's for girls.

Uh... okay. Cool. I'll try not to burn down the house with my wife and kids in it, for the girls in it.

Complete. 12.8V 280Ah for about £500. Surprisingly large and heavy, similar to lead acid! I thought LiFePO4 was smaller and lighter?

It's smaller and lighter, especially if you're looking at derating for temperature and such. Just not as much as most people assume.

The 12.8V/400Ah EG4-LL is just under 100 pounds. The Trojan SPRE 06-415s are a similar rated capacity (somewhat less in practice, but they're broadly close), and a pair of them to make a 12V system would be 236 pounds. So, slightly more than twice as much for a similar capability.

My wife raising the temperature some Tuesday afternoon because one of our kids is taking a bath doesn't mean that the temperature needs to go up every Tuesday afternoon from there on out.

We've gone over this before, and I find nothing interesting about re-litigating it. You prefer to ignore the rules and build as cheaply as possible, my social group and I prefer to build better-quality-than-professionals sort of stuff for radically less money than it pays to get someone to slap it together. It's not hard to do it right, not significantly more expensive in materials, and it tends to both perform better long term and avoid some of the more energetic failure modes that seem to get YouTube views.

Bare cells, or complete packs with BMS?

If you're power limited, underclocking/undervolting (or just reducing the power limits, which gets you the same thing on any modern bit of silicon) will improve compute per joule substantially.

I can think of half a dozen ways to do it. But I'm a programmer, and I operate in the Linux ecosystem.

The house system is 15.9kW of panel, though optimized for "long solar day" production vs "peak kWh per panel kW," given what I expected to happen with net metering agreements out here.

For a DIY, code compliant

ground mound, grid tie solar install around here, $1/W is doable (I know someone who's done that), but batteries are just expensive.

That adds a LOT of power consumption for only marginally additional compute power. I'd be surprised if you got more than about 10-15% extra compute from the 50% bump in power limit. If you're power limited, go the other way. I run my 2080 (240W nominal power limit) at 125W quite a bit of the time, and it definitely isn't halving compute power.

Yup. I poke the "suspend time" a couple times throughout the year, will manually change things as needed, but I've avoided too much automation on it. I just don't find automation helpful for a lot of this stuff, and I've seen it go badly wrong more than a few times. It's not a production system, it's a hobby system, but "the rest of my office" is a production system (I work from here), so I err on the side of battery state of charge when needed.

But I'm seriously overpaneled out here, so can make up a lot of it on "Well, I screwed that up, but 5kW of panels solves a lot."

... but that was 3 grand (UK money) of panels and batteries

I haven't totaled up my system... it's certainly far more,

but I also have a system suited to a small house

The same goes for GPUs - you can lower the power use on them, and substantially increase compute-per-joule.

But you can have a sunny week or a rainy week, where presumably you adjust something. Do you get computers to run for half the day? Or reduce the cores used?

If it's a sunny week, there's nothing to adjust. The computers just run. If it's particularly hot, I may let them sleep overnight to avoid cooling loads, though I'm planning to move some hardware into a box outside with filtered vent fans this year to help reduce the summer cooling demand.

If it's rainy, I'll only run one computer at a time, or let them sleep, though I try to avoid grabbing too many short-lived tasks if I know the weather is going to be cloudy in the next week or so - I just set my machines to not grab new tasks, drain them out, and wait until I have more power.

Solar and Boinc is no good for long tasks. Solar requires variation of the computer power.

I don't try to match instant power demand to solar production...........But there's also another thread, specifically related to off-grid solar, better suited to informing me how what I'm doing can't possibly be working.