electrical safety and seldom used peripherals

  jack 08:53 24 Apr 2007
Locked

In a recent string a poster was commenting on the fact that his scanner kept coming on ,when he infact was not using it and was worried about the life of the unit.
Various answers ensued from unplugging it from mains and inserting a switch in the line .
discussing this with a chum yesterday over a cuppa at the Nat History Museum raised this very query -what should he do about it.
He was all going for inserting a switch as unplugging it from the power strip buried under the desk would be a tad inconvenient.
And this raised the question- His scanner is powered from an 'In-plug' power supply in the power strip under the desk so he is contemplating inserting a switch in to the low voltage line to the scanner.
Is this a safe thing to do?
That is leaving a power supply connected to the main with no active outlet?

  €dstowe 09:16 24 Apr 2007

Is this a safe thing to do? NO!

Doing this leaves the low voltage converter still connected. Why not just remove from the power strip?

Other than that, remove the plug from the back of the scanner. That does leave the power unit still attached though - wasting energy and, small though it may be, a fire risk.

  €dstowe 09:17 24 Apr 2007

I should have added:

Move the power strip to somewhere more convenient - there may be other items that could be unplugged.

  wee eddie 09:20 24 Apr 2007

If you leave a Transformer plugged into the Mains, it consumes power whether it is drawing current or not.

For the approximate amount of power, see the articles relating to leaving Mobile Phone Chargers plugged in.

Un-plug it or switch that socket off.

  Diemmess 09:36 24 Apr 2007

Lash-ups take over when different situations interfere with original good intentions.

My own arrangement became similarly awkward to Jack's friend.
In my case the main sockets were behind a heavy victorian knee hole desk.

Now its not perfection, but safe.
I wall surface mounted a single switched socket, fed by flex from a plug into a conventional socket which is normally out of reach.

Now, at close of play, a single switch isolates the lot.
There is a real economic benefit as well as the safety angle.
click here

  Grantrh 12:15 24 Apr 2007

I have this problem too - I purchased a switched power supply such as this:
click here

  rodriguez 12:31 24 Apr 2007

Grantrh's suggestion is probably the best - you can then switch off each of the devices plugged in without having to unplug them.

  octal 13:02 24 Apr 2007

Yes you are correct, it's called eddy losses, that's what happens when the AC electricity is constantly changing the magnetic direction in the core. If the transformer has not got a load, energy is dissipated in the core in the form of heat.

  Diemmess 13:40 24 Apr 2007

The point in both the original post and my own is that the power strip is inaccessible without a lot of shifting and pushing.

In my case by connecting a new surface switched socket, accessible above and fed from below the desk, the power strip and everything else takes mains power from this one socket which is switched off after normal shut down.

In the long term if it is no longer needed, there is minimal effort to remove it leaving only two small screw holes.

  jack 16:49 24 Apr 2007

Thank you one and all - I think this will convince him that the way to go is unplug the mains unit,it may mean a little re arranging on his part- but he has a big desk.
I am fortunate that the Epson scanner I have, its PSU
is separate from the mains plug via a 'Philips' flat two pin lead -a simple matter to keep the PSU near by and and disconnect from the lead.

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