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

 

[topquark]

there is no way a plug will have arcing on it if the load is switched off.

thats it.....no load...no arc.

OK. So what is the load with a giraffe generator?

 

[telectrix]

45 posts to get nowhere. could have rewired the circuit by now.

 

[topquark]

there is no way a plug will have arcing on it if the load is switched off.

thats it.....no load...no arc.

What would happen with a high/medium/low resistance short in the plug, explain your reasoning (4 points)?

 

[RogertheBodger]

Lets have a beer, everyone else is.

45 posts to get nowhere. could have rewired the circuit by now.

 

[SMB]

I don't think a live/neutral reversal would cause any more or less arcing than a correctly wired socket. I also don't think it make a difference to the arc length or duration if the neutral was switched instead of the live. Static would discharge to the first earth available so this would happen before the plug was pulled out. I would guess at wear and tear on the internal brass rings of the socket. Possibly the outer edge of the ring is a loose fit on the plug pin as a result of plugs being inserted slightly skew over the years and this loose momentary contact with the plug pins as it's withdrawn is causing excessive arcing. The short answer I would say is replace the socket and the plug for good measure.

from my understanding 'double pole switching' could be the issue here.

if the socket does not have 'double pole switching' or the polarity is incorrect then the load will not be switched off when the socket is switched off and the load will arc when the plug is pulled out because the load has not been isolated.

reverse polarity or faulty socket.











perhaps?

 

[topquark]

I don't think a live/neutral reversal would cause any more or less arcing than a correctly wired socket. I also don't think it make a difference to the arc length or duration if the neutral was switched instead of the live. Static would discharge to the first earth available so this would happen before the plug was pulled out. I would guess at wear and tear on the internal brass rings of the socket. Possibly the outer edge of the ring is a loose fit on the plug pin as a result of plugs being inserted slightly skew over the years and this loose momentary contact with the plug pins as it's withdrawn is causing excessive arcing. The short answer I would say is replace the socket and the plug for good measure.

Do you think it makes a difference if it's an AC or DC load on the socket? IE an appliance that has a transformer?

 

[SMB]

What would happen with a high/medium/low resistance short in the plug, explain your reasoning (4 points)?

im afraid i dont really understand what your asking.

Im not trying to be clever.




If a socket outlet is arcing when you un-plug your kettle and the socket outlet is turned off, then what would you think?

easy innit.




snore.

 

[topquark]

Sorry, was trying to illustrate that the appliance being "off" doesn't mean much. There are other routes for current flow as soon as any device is plugged in to a socket.

I'll shut up and go away now.

 

[telectrix]

now we are digressing to the point of total and utter confusion.

need another beer to restore my sanity.

and a couple of funny smokes

where's that channel 4 programme being done?

my straitjacket is at the cleaners

and iv'e not fed the dragons yet.

van needs cleaning

lawn wants mowing

 

[SMB]

i would not suggest you go away.

explain if you would like to try to.





if an applience is plugged in and the socket switch is turned off then there should never be any arcing.

unless there is a problem....

ie

the socket is de-funct...or the socket does not have double pole switching and the polarity is incorrect.

 

[Marvo]

I don't think a live/neutral reversal would cause any more or less arcing than a correctly wired socket. I also don't think it make a difference to the arc length or duration if the neutral was switched instead of the live. Static would discharge to the first earth available so this would happen before the plug was pulled out. I would guess at wear and tear on the internal brass rings of the socket. Possibly the outer edge of the ring is a loose fit on the plug pin as a result of plugs being inserted slightly skew over the years and this loose momentary contact with the plug pins as it's withdrawn is causing excessive arcing. The short answer I would say is replace the socket and the plug for good measure.

from my understanding 'double pole switching' could be the issue here.

if the socket does not have 'double pole switching' or the polarity is incorrect then the load will not be switched off when the socket is switched off and the load will arc when the plug is pulled out because the load has not been isolated.

reverse polarity or faulty socket.
perhaps?

Sorry, I re-read the OP and if the switch is working then it can only be earth leakage current causing the flashing. I've seen a few appliances from the Far East where the power indicator neon is wired with one leg to earth but I'm not sure if this would present sufficient path to earth for an arc if there was leakage through it. I've also seen a problem with an old CRT type TV where the antenna amplifier in the loft caused a surface voltage (measured 106v with digital tester but only around 5volts with analogue) on the chassis of the TV, you could get what felt like a static shock from the TV when it was unplugged but again I'm not sure it would have been enough leakage to cause an arc when it was unplugged.

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

 

[SMB]

laugh.

i might take up a new hobby...


Electrics.....?





nah......fishing?

 

[topquark]

i would not suggest you go away.

explain if you would like to try to.





if an applience is plugged in and the socket switch is turned off the there should never be any arcing.

unless there is a problem....

ie

the socket is de-funct...or the socket does not have double pole switching and the polarity is incorrect.

Ang on, just sent you a PM ... will paste it here if that's OK?

 

[Sintra]

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

The outcome i am getting is that there is a flash from what should be the live terminal of the socket. My reckoning as to why this is happening is that the circuit is trying to flow from the neutral pin of the socket into the neutral pin of the plug top. Then through the appliance and back to the live pin on the plug top. Now with circuit broken at the point between the live pin of the plug and the live pin of the socket the pin on the plug will be at line potential so when inserting into and removing it from the plug causing an arc.

PS I have carried this experiment out in a controlled way and haven't put any members of the public in any danger.

 

[topquark]

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

The outcome i am getting is that there is a flash from what should be the live terminal of the socket. My reckoning as to why this is happening is that the circuit is trying to flow from the neutral pin of the socket into the neutral pin of the plug top. Then through the appliance and back to the live pin on the plug top. Now with circuit broken at the point between the live pin of the plug and the live pin of the socket the pin on the plug will be at line potential so when inserting into and removing it from the plug causing an arc.

PS I have carried this experiment out in a controlled way and haven't put any members of the public in any danger.

and no Giraffe's either I hope!