electricity in my place here is just plain weird

[irbirb]

Of course, poly-phase feeds can cause problems if one is not careful. I had a telephone technician blow two computers and interface boards before he called for help. It turned out that the outlets in the room were on different phases. The telephone switch was on one and the outlet he plugged his service PC into was on another causing a 208 VAC differential between the two hot sides instead of the expected 0 VAC. This was in Manhattan but it could have been almost anywhere.

hmmmmm. the electricity in my place here is just plain weird sometimes.
i wonder if that's not somehow related to it coming in as 3 phase.

 

[Reloadron]

hmmmmm. the electricity in my place here is just plain weird sometimes.
i wonder if that's not somehow related to it coming in as 3 phase.

Guess it depends on where your place is, and the definition of weird.

Also how it is configured.

Ron

 

[irbirb]

Guess it depends on where your place is, and the definition of weird.
Also how it is configured.

ah, yeah. well it's 3x240/400 @ 50Hz, 120° star arrangement. europe.

as for the weirdness...
okay, so, quite regularly i'm working with two laptops at the same time. both computers are basically the same, and both have metal (aluminum) cases.
it's not a nice idea to touch both laptops at the same time... the buzzing sensation this causes is quite uncomfortable, makes one swear loudly. not a static shock... just a current of some kind.

to make it more annoying, it's not always happening.
some days everything seems pretty normal.

there's all kinds of external harddrives, audio gear, and some video stuff connected.. i kind of figured that it's one of those peripheral devices making weird with it's smps or something. everything is on the same circuit (except lighting), so i'm not really inclined to suspect the poly-phase, but it's weird.

 

[Nigel Goodwin]

The situation in England is that the mains power is 230 V to ground, 400 V between phases.

To be more correct, UK mains power is 240V - it's only 'nominally' 230V.

In the past the UK was 240 and the rest of Europe 220V - so it was standardised at 230V - but this was only a theoretical change, we're still 240 and the rest still 220.

Both fall within tolerance of 230V, and all electrical goods now are rated at 230V, so they work on either 220 or 240.

Back before this happened 220V products from Europe commonly had short lives in the UK as 240V was just too high, and mains transformers very commonly failed.

 

[RODALCO]

-irbirb-
Are both computers fed from the same socket ?
It looks that one of the SMPS caps is on the way out and causes static voltage to built up on the outside casing.
It shouldn't make any difference if you have three phase star. as the computer only draws power off one phase to the neutral.
Unless the neutral is bad because of a loose connection, fluctuating voltages may occur.

 

[Reloadron]

My guess, and only a guess, would be a grounding issue. That or an incorrectly wired outlet? My personal laptop uses a 3 wire grounded plug to AC mains and that ground continues through the AC adapter/charger to the laptop frame. Ground is ground and that being true if correctly wired a hot case or chassis should be grounded. A grounded chassis or case to another grounded chassis or case should have a potential difference of zero volts (give or take a few ground loop mV).

Have you ever used a meter to actually measure the potential difference?

Ron

 

[KeepItSimpleStupid]

I'll go with the grounding issue. Been there, done that. 60 VAC between grounds and I can explain why.

 

[Gary B]

ah, yeah. well it's 3x240/400 @ 50Hz, 120° star arrangement. europe.

as for the weirdness...
okay, so, quite regularly i'm working with two laptops at the same time. both computers are basically the same, and both have metal (aluminum) cases.
it's not a nice idea to touch both laptops at the same time... the buzzing sensation this causes is quite uncomfortable, makes one swear loudly. not a static shock... just a current of some kind.

to make it more annoying, it's not always happening.
some days everything seems pretty normal.

there's all kinds of external harddrives, audio gear, and some video stuff connected.. i kind of figured that it's one of those peripheral devices making weird with it's smps or something. everything is on the same circuit (except lighting), so i'm not really inclined to suspect the poly-phase, but it's weird.

That is a symptom of either a polarity reversal, most likely, or split phase, less likely.

 

[irbirb]

Have you ever used a meter to actually measure the potential difference?

okay. wasn't doing anything yesterday, but today yes.

70VAC between cases. 100VAC if i unplug the firewire.
80 with no external monitor, 93 if i unplug the ethernet.

pretty wacky.

i'm going to go ahead and ground both laptops' power supplies instead of just one and... 114VAC

I'll go with the grounding issue. Been there, done that. 60 VAC between grounds and I can explain why.

yes i'd be curious of your answer.
i'm starting to formulate my own guess also.

That is a symptom of either a polarity reversal, most likely, or split phase, less likely.

i've been one to switch the AC plugs as helping to deal with ground-loop issues before. have even had some amplifiers with a built in polarity switch.... but that was in canada, and in this case it's having no effect.

 

[KeepItSimpleStupid]

OK, my answer that has happened to me. Picture an RF filter such as the one here: EP/VP Series The moddle cap is supplying one of the grounds and one of the grounds is lifted. I've seen it on outlet strips and I've seen it on individual outlets. On the individual outlets, the ground would lift when two devices were plugged in. There were 430 outlets in our building that potentially needed to be replaced. That drove me nuts. Very hard to detect, but I did develop a test for it.

We had this device which somebody made off with it with the 5 finger discount, but I'd love to find one again. It had 3 lights just like an standard outlet test and a GND lamp that checked the ground resistance and illuminated when it was bad. It looked like a can of vegtables. Not sure if Ideal's Suretest would work.

Because the caps are roughly the same the voltage is based on the volatage divider efect of the reactances. This is ABOUT 1/2 the line voltage.

This was two problems that I have personally seen. Two people tried for 8 hours to solve it. I solved it in 5.

 

[irbirb]

Because the caps are roughly the same the voltage is based on the volatage divider efect of the reactances. This is ABOUT 1/2 the line voltage.

This was two problems that I have personally seen. Two people tried for 8 hours to solve it. I solved it in 5.

well, shoot. no filters or ground lifts here as far as i can see. there's the meter, the breakers.. i see where it's grounded to the water pi.... wait a second, that's the gas pipe...weird...okay and there the ground wire continues into the hall-way and connects to... okay, well i think that's a water pipe.

 

[KeepItSimpleStupid]

The switching power supply has the filter in it. All you need to wreck havoc is two switching power supplies with a 3-wire cord (laptops), an outlet strip and no ground or a good ground and a bad outlet strip and probably other ways to create the glitch.