Problems with 'flashing' sockets!

[tom-the-sparky]

Hi Everybody,

Has anyone encountered 'flashing' sockets before? A client has a problem with plug in appliances in that when the socket outlet switch has been turned off, and the item removed an electrical spark/arc occurs?

Any ideas about this oh wise ones?

Thanks

 

[telectrix]

and of course, no electricians ( or apprentices ) were harmed during the filming of the experiment

 

[topquark]

It will, to some extent, depend on the load.

This is the text of the PM I sent to @SMB:

The point I was trying to make is that it won't make any difference if the appliance is "off" for the same reason as the socket. IE that the appliance will be switched in the same way as the socket, IE on the line side. So anything that's plugged in will be live (and may be a load ... ie transformer with capacitor, short etc).

Hope that makes sense mate

Cheers
Martin ...

 

[Marvo]

Don't try this at home but I have reversed the polarity on a socket to put the theory to the test.

Is the socket switch single pole or are the live and neutral switched?
What appliance are you plugging in for your test?

 

[SMB]

I think I need to start drinking again, I feel a bit left out on this thread :-(

Marvo...you are one of the more intelligent people here.....please don't start drinking.

 

[SMB]

Sintra.....live electricution....i wish i had a web-cam.

 

[Sintra]

Don't try this at home but I have reversed the polarity on a socket to put the theory?[QUOTE/]
Is the socket switch single pole or are the live and neutral switched?
What appliance are you plugging in for your test?

Tried it with an old iron that was in the shed.

The socket has single pole switching.

 

[Sintra]

Sintra.....live electricution....i wish i had a web-cam.

Sintra not dead yet.

 

[topquark]

Tried it with an old iron that was in the shed.

So the load there will be the element, when plugged in it will draw a current as a load (even more if the element is starting to breaking down).

 

[Marvo]

Lol, what's going on with the bb-code on this thread? I never said that Topquark

 

[topquark]

Lol, what's going on with the bb-code on this thread? I never said that Topquark

Ooops, that'll be me trying to highlight something when rat *****! ... I'll edit it now

 

[SMB]

Tried it with an old iron that was in the shed.

The socket has single pole switching.

how big was the arc ?

 

[topquark]

Ooops, that'll be me trying to highlight something when rat *****! ... I'll edit it now

Hmmm, well I can't edit the post so not sure what's happened there. Perhaps some kind moderator could do the honours.

 

[pushrod]

Cheers sintra. Had just worked out (on the back of an envelope) that with the switch in the neutral (cross polarity) and with the switch off you would still have the possibility of arcing. As you have seen.

Just before the plug is pulled the N socket terminal is at 230V and so is the N pin of the plug. (even though the switch is open and no current flowing)

At the moment of separation the N pin falls to 0V but the N terminal of the socket is still at 230V so you get your arc.

If the switch was in the line and open, both the terminal of the socket and the pin of the plug should be at 0V so when they are separated there is no arc.

Nice thinking Tel but

 

[topquark]

Cheers sintra. Had just worked out (on the back of an envelope) that with the switch in the neutral (cross polarity) and with the switch off you would still have the possibility of arcing. As you have seen.

Just before the plug is pulled the N socket terminal is at 230V and so is the N pin of the plug. (even though the switch is open and no current flowing)

At the moment of separation the N pin falls to 0V but the N terminal of the socket is still at 230V so you get your arc.

If the switch was in the line and open, both the terminal of the socket and the pin of the plug should be at 0V so when they are separated there is no arc.

Nice thinking Tel but

Eligantly put, have a beer!

 

[RogertheBodger]

Well I,ve had a beer to get up to speed on this thread, but my one beer brain still can't get around the idea that if the single socket switch is off, there can be no circuit, no load and no arc, reverse polarity or not.

It was the only beer in the fridge too so we need to sort this quick.