Everything is normal (by alaric)

I'm back in Cranham after another week away. I came back late on Friday, and the first thing we did Saturday morning was go and pick the van up from Holbrook Garage, where it had been in for some minor repairs: the reversing lights had stopped working, the right headlight was being intermittent (sidelight and full beam mode worked OK, but when set to dip, it was merely sidelight-bright, but sometimes it worked OK), and the coolant temperature gauge only ever read above 'very cold' when we were sat in a creeping traffic jam in bright sunlight for a few hours.

All niggling little things that I had wanted fixed for a long time, and had had brief attempts to fix myself, but now we have some money coming in, fixing niggling little problems like that is on the cards once more (before they become expensive problems).

The van was ready and waiting for me, and the first thing we noticed as Sarah and I set off down the M5 for a day out was that the temperature gauge did indeed rise until it gratifyingly pointed to "Normal":

It's nice to know you're normal.

Anyway, we proceeded to visit Bristol for lunch and a walk about, then headed over to explore Weston Super Mare and see the seaside (even though it's not really the sea per se, it's the Severn Estuary), before making our way back home.

Then on Sunday we took Jean out. We tried to go to Bristol Zoo, but all the car parks were full, which lead us to suspect it would not be a pleasant time to visit, so instead we walked around Bristol again with her.

We came across a green square, where some air cadets where dismantling a glider and putting it in its trailer, while some army cadets were taking down a portable climbing wall. I presume there had been some kind of event on, which we had missed, but Jean was entranced by the glider. She demanded to go and see it, shouting "Plane! Plane!". Afterwards, we saw some people doing acrobatic leaps in the square, and Jean tried to copy them, which was rather cutely comical, too.

We had a relaxing weekend, since we'd both had a hard week beforehand (I worked all day and spent most of my evenings in a data centre fixing things!), and we have a hard week ahead of us.

Which I am now starting... with a bad cold. Sigh...

Big Voltmeter (by alaric)

My mate Seth brought me back a lovely big AC voltmeter from India, where the power distribution systems tend to reflect an earlier, more exciting, time where things arced and crackled, and everything was made of Bakelite.

Anyway, it's meant to mount on a panel, and the rear of it just has two exposed screw terminals. So I had to do a bit of work to make it usable.

Firstly, I obtained some crimp terminals - a nice set with eighteen different kinds, including rings, spades (male and female), forks, and butt splices in three different sizes.

Anyway, I really wanted it for the ring terminals, which would securely attach to the screws on the back of the voltmeter. So upon returning to home, I went to Maplin and obtained a large enough box, then spent a pleasant hour or so in the workshop with my father in law drilling holes in the box so that I could mount the voltemeter on it. We also scraped away some paint from the inside of the mounting holes, exposing the bare metal, so that I could attach another ring crimp terminal to the mounting bolt as an earth connection. Better safe than sorry!

The end result is a nice box with the voltmeter mounted on it, with no exposed live metalwork, and a standard mains plug on the other end so it can monitor my mains voltage. This is a pretty useful tool, since we do get power cuts and brownouts and so on quite often out here, and the lights often change brightness at random...

As I write, it's reading a bit over 230v, while earlier, it was reading more like 225v. At some point I'll ask Sarah to turn the shower on (our biggest load) and we'll see how much the voltage drops - because I know the lights usually dim when the shower comes on 🙂

People leave cool things on the kerbside in London (by alaric)

Like this rather large power supply, spotted on Tottenham Court Road:

I'm glad I didn't have the van, or I'd have felt compelled to take it home and try to fix it!

Backup Power (by alaric)

As I have mentioned before, we have a petrol genset that we use to keep things going during our frequent power cuts. Immediately after the flood, too, when we had to shut down the house power since one of the outlets was submerged, I ran the computers off of the genset.

However, it is a pain to have to run the nice cable I made around the house, reach behind a filing cabinet to unplug the UPS that feeds the computers from the wall and plug it into the generator cable, unplug the fridge freezer, stretch cables about, etc...

So the logical next step would be to fit a second consumer unit, move the 5A lighting circuit over to it, and run a 15A circuit to a few strategically placed sockets around the house - where fridges and freezers are likely to ever be, and of course, up in the office where the computers live, and where the incoming phone lines are (where the ADSL router goes).

This consumer unit can run from a single 30A fuse in the main consumer unit (the slot currently taken by the lighting circuit will do nicely), but via a pair of 32A IEC 60309 connectors. The circuit from the main consumer unit would come out via a female socket, and the feed into the new consumer unit via a male socket.

Then the two can be connected by a short length of 32A cable with appropriate plugs on each end. And when the power goes down, I can turn the emergency circuit off with the master switch on the secondary consumer unit (because it's bad to use a plug and socket as a switch, interrupting a flowing current and arcing in the process), unplug from the useless incoming circuit, and plug into the genset's output... The genset can only produce about 10A; in practice, that's more than enough to run everything, and it has a 16A outlet on the front, but I'd feel compelled to see if I could find a 10A circuit breaker nonetheless, since with proper sockets stationed about the house, it might be easy to accidentally overload it. But I'm designing the system around a standard 15A socket circuit and a 5A lighting circuit, so that in future, I can get a bigger genset and power more stuff without needing to rewire it all.

What I wonder, though, is if this arrangement would actually be legal under the stringent UK wiring laws. As far as I know there's nothing wrong with having a 32A socket coming from a 30A fuse (after all, a standard 15A circuit feeds many 13A outlets); the question is, is it OK to have a lighting circuit and a set of outlets coming from a consumer unit fed from a 32A inlet socket?

I hope so, since it'd really make switching over to backup power easier than it currently is. And since anything I connect between those two sockets isn't a fixed part of the house wiring it would, I presume, not be governed by regulations, so fiddling with alternate power sources (such as turbines and battery arrays) would be a lot easier.

CSS (by alaric)

I read this interesting article, which I found via reddit:

Lexical File Names in Plan 9 or Getting Dot-Dot Right

I found I liked the styling. At first I'd assumed it was a PDF, since it looked like the output of TeX or Lout, but it was suspiciously in a web browser rather than a PDF viewer.

"Oooh," I thought, "I wonder if the CSS they used for that is freely licensed? I'd quite like to use it to give my own writings that academic feel, so that people trust them uncritically, thus advancing my world domination plans."

But upon viewing the source, I had a nasty shock - every element was individually styled with its own style= element. Ugh. Looked like something had autogenerated it, most likely from something intended to be turned into a PDF. The result looked lovely, but was implemented terribly.

So I decided I'd sharpen my decidely rusty CSS skills a bit by cloning it properly.

The end result isn't a perfect copy, but looks good enough for me, and I'd like to share it if anybody else wants it. Here's a sample of it in use. And feel free to download and copy the CSS, subject to the nice license at the top.