Hi folks,

First a quick "hello" since I'm a long-time lurker but this is my first post. I'm not a professional EC but do have a degree in Electrical and Electronic Engineering (wow, dangerous!). I've been fascinated by electricity for as long as I know, and having my Dad working at a power station during my formative years certainly helped light the fire. I progressed to electronics and then to IT (boo, hiss!) At the moment I'm working for what remains of the UK computer industry, formerly ICL, where we still make a meagre income from Mainframe computers. This won't last forever though, and a change of career may be on the cards...

Ok, to my question. Over the past couple of days the lights here at home have been flickering briefly, like they sometimes do in a thunderstorm, sometimes several times in succession a few seconds apart, other times not for a while. Working on the computer yesterday I noticed that the UPS was switching to battery for a few seconds each time too, and decided to try and find out what was going on, since this is most unusual and we're in the middle of town (Manchester, UK) with no local overhead wiring.

Finally managed to capture a blip on the 'scope:

[Linked Image from jusme.com]

The blue top trace is the secondary of a small LV transformer, the flat tops are probably from all the computer gear running on this ring!

Looks like something is arcing over on the peak, then clearing by the next cycle, or could it be HV switchgear somewhere? Could it be a local fault (no sign of smoke coming from the panel!)

I'm getting slightly worried by it, since it's been happening for two days now. Any suggestions?

Ian.