How does an electrician assess the size of existing conductors when he rocks up to a property to do a job?
Let's say he's adding a circuit and needs to decide whether the meter tails are 16mm^2 or 25mm^2 (or something else - imperial?). He could disconnect them and get out his callipers but that would mean popping the main fuse. Surely not for every job? Is there a trick to this?
Alex
You just can tell by looking and experience. It just the same as when my mechanic brother does some work on my van - he looks and thens says "pass me a 11mm socket".
Alas, I'm not there yet. Had a look in B&Q and could only tell 16 and
25 apart by weight. Admittedly looking through the shrink wrap but still.The situation I'm faced with is an economy 7 meter with two sets of meter tails feeding henley blocks, which branch off to 6 encosures/CUs with a variety of cabling. Some connected by more 'tails' (not sure you can call them tails really once they've branched) including some braided-fabric ones, other with 2-core flat sheathed cable. I'm trying to assess whether any of them are overloaded or unsafe.
Alex
One of my colleagues once listened to a mainframe booting, then said "it's only using half of the memory"....!
I can tell by listening to the dialtone whether the service is via a DACS.
They *** TALK *** to you as they boot!
Have diagnosed several hard-looping programs from sound alone. (That is, that fact of, not which program.)
When I was working for a minicomputer manufacturer many years ago, I was standing in the computer room talking with the operators whilst waiting for a System Generation to finish on my dev system. System Generation was our equivalent of a kernel build, and took around an hour, during which it went through 8 well defined phases. I had a new graduate working with me, and he said we better check if the System Generation had finished, and I replied without looking that it was still running Phase 7. He asked how I knew, and the answer was that I knew the sounds the disk head movement made during each phase. (These were 14" platter washing-machine sized drives, with 80Mb disk packs in them.) He was well impressed, and it became a long standing joke.
Old story but true. I can - or could - do the same booting PC unixes. Watching the disk light flicker.
Same here. But on PDP-11 UNIXes....!
The speakers on mainframes were incredibly useful. I could pretty well tell how our 2960 was running by listening to it.
I keep some labelled 8-inch lengths to compare with.
JGH
:-0
Owain
It's girth not length that matters.
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