Power surge over CAT5 ethernet?

[Jog On]

Got a weird one here at the moment.

A group of machines all in the same area randomly powering off and starting up (just the base units). The electricians are adamant that it's not a power problem, we've put in surge protected plug adaptors but it's still happening. They've put in some electrical measuring doo-dah that's not reporting anything out of the ordinary.

So far we've swapped out 2 of the machines with brand new ones and it's still happening. The electrics guys are trying to convince us that it's a PC problem still but it only ever happens to these 4 machines in the same little area of the entire office and absolutely nowhere else…..

Is it possible that power surges/spikes/shorts can happen over ethernet maybe from a dodgy switch? The electrics guys say that all the machines are on different circuits and because it's only happening to the base units and not the screens "maybe it’s a software problem"….. (yeah fooking right!)

I'm pretty sure it's electrical but I'd like to rule out the possibility of a problem in the switch because they are patched into the same switch. I know there is such a thing as power over ethernet but I'm pretty sure the hardware has to be specialised for power to travel over ethernet (haven't investigated fully - doing that now)

It does only seem to happen when they are doing networky type things like printing, saving a file and eve in one case accepting the dialogue box requesting permission for me to remote control one of their machines…

Anyone got any ideas?

[Kyajae]

Got a weird one here at the moment.

A group of machines all in the same area randomly powering off and starting up (just the base units). The electricians are adamant that it's not a power problem, we've put in surge protected plug adaptors but it's still happening. They've put in some electrical measuring doo-dah that's not reporting anything out of the ordinary.

So far we've swapped out 2 of the machines with brand new ones and it's still happening. The electrics guys are trying to convince us that it's a PC problem still but it only ever happens to these 4 machines in the same little area of the entire office and absolutely nowhere else…..

Is it possible that power surges/spikes/shorts can happen over ethernet maybe from a dodgy switch? The electrics guys say that all the machines are on different circuits and because it's only happening to the base units and not the screens "maybe it’s a software problem"….. (yeah fooking right!)

I'm pretty sure it's electrical but I'd like to rule out the possibility of a problem in the switch because they are patched into the same switch. I know there is such a thing as power over ethernet but I'm pretty sure the hardware has to be specialised for power to travel over ethernet (haven't investigated fully - doing that now)

It does only seem to happen when they are doing networky type things like printing, saving a file and eve in one case accepting the dialogue box requesting permission for me to remote control one of their machines…

Anyone got any ideas?

Even if it was the electrical supply, the thing about the monitors means nothing as they would power on almost immediately. It can't be software related on 4 machines - too coincidental.

This sounds like the electrical supply is suffering a brown-out, i.e. the voltage drops momentarily enough for the ACPI BIOS to kick in a reboot.

Do you have a spare UPS avaialbe perhaps to run one PC on. If you do get a brown out the UPS alarm will trigger as it supplies power during voltage loss - source of problem sorted.

[NoddY]

Even if it was the electrical supply, the thing about the monitors means nothing as they would power on almost immediately. It can't be software related on 4 machines - too coincidental.

This sounds like the electrical supply is suffering a brown-out, i.e. the voltage drops momentarily enough for the ACPI BIOS to kick in a reboot.

Do you have a spare UPS avaialbe perhaps to run one PC on. If you do get a brown out the UPS alarm will trigger as it supplies power during voltage loss - source of problem sorted.

I agree. I had a similar problem in the house - reboots for seemingly no reason. It did turn out to the quality of supply. What convinced the man from the electric board was the lights slightly flickering and buzzing.

What was interesting was their solution. He said they would send a massive current through the cables in the street to 'melt them' and this would improve their conductivity! And it worked.

[buffdaddy]

I think your power outlet is overloaded (the old V=IR)

Voltage is constant (220-240 volts)
Resistence (load) varies. If this goes up, the current supplied to the computers will drop, forcing a reboot

Try to run a lead onto another "area" which is not too loaded and therefore spread the load.

[VectraMan]

I thought it was possible to get a DC current along a network cable if you have different equipment on different mains supplies. The answer is an optical link. But I certainly don't claim to be an expert.

Sounds more likely to be the brown out theory. Get a UPS?

[Jog On]

Going with the UPS chaps and chapesses. (I'll propose to the client they buy one to test this out)

Many thanks to y'all and that.

Much appreciated and if y'all in the west end sometime the drinks are on me.

*I have no idea where that deep southern US accent came from but the West end offer remains the same*

[Paddy]

Got a weird one here at the moment.

A group of machines all in the same area randomly powering off and starting up (just the base units). The electricians are adamant that it's not a power problem, we've put in surge protected plug adaptors but it's still happening. They've put in some electrical measuring doo-dah that's not reporting anything out of the ordinary.

So far we've swapped out 2 of the machines with brand new ones and it's still happening. The electrics guys are trying to convince us that it's a PC problem still but it only ever happens to these 4 machines in the same little area of the entire office and absolutely nowhere else…..

Is it possible that power surges/spikes/shorts can happen over ethernet maybe from a dodgy switch? The electrics guys say that all the machines are on different circuits and because it's only happening to the base units and not the screens "maybe it’s a software problem"….. (yeah fooking right!)

I'm pretty sure it's electrical but I'd like to rule out the possibility of a problem in the switch because they are patched into the same switch. I know there is such a thing as power over ethernet but I'm pretty sure the hardware has to be specialised for power to travel over ethernet (haven't investigated fully - doing that now)

It does only seem to happen when they are doing networky type things like printing, saving a file and eve in one case accepting the dialogue box requesting permission for me to remote control one of their machines…

Anyone got any ideas?

Never believe an electrician.

Surge protectors can cause more problems than what they are worth so best remove them for trouble shooting purposes.

If you have a clean power supply, use an extension cable or move one PC to a new power outlet.

Try running a PC from a proper UPS.

Start cross swapping PC parts one at a time and back again with a known working PC.

Problems are most likely to be with RAM or system boards and then PSUs.

Many years ago I worked for a third party maintenance company, it was not unusual to get batches of new PC failing on the same faulty component at the same time but in various parts of the country. Eg: If a system board failed on a new model after six weeks of use you could safely bet a dozen others would do so in a matter of days.

Mains monitoring is a whole branch of science on it's own and you need special equipment to monitor the sin waves properly. (frequency, strength, noise, synchronization and even the curvature of the sin wave). If you have access to an oscilloscope (buy one on ebay?) it will help.