Imac giving electric shocks. Should I return? Updated, Still not Solved

ding76uk

ding76uk

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Carl
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I have got the 27 inch imac i7, and am getting mad static electric (or otherwise electric) to the point of mini shocks when I tried to switch it on today.
It is coming from the back of the screen and is really quite severe.

Anyone else had problems with this? I am wondering whether I need to return my mac to Apple as I dont want to fry all my data and backups using this machine.

The computer is running on an extension plug if that makes any difference.
 
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Wearing nylon or other synthetic 'garments' can create unwanted static. :$
 
It's the patented jobs negative stimuli to make you buy more Apple Products. It reads your mind and everytime it senses "windows" or "pc" you get shocked.

:)
 
PsiFox said:
It's the patented jobs negative stimuli to make you buy more Apple Products. It reads your mind and everytime it senses "windows" or "pc" you get shocked.

:)
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Well I have been using paralells at work today:D

Just found out what it is. Bloody electrician has messed up putting in power to our wall mounted telly as you can feel the electric coming out of the wall to it, only discovered when turning mac off and felt all my arm hairs tingling. Changed plugs and presto no shocks and luckily for him one working mac with all backup drives fully functioning.

Electrician is about to get a nice call. Least mac is not messed up by it! Would have been more short and sweet if it was.
 
That electrician wants reporting! What else could have have screwed up?!
 
Earth and Neutral swapped?
 
arad85 said:
Earth and Neutral swapped?
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You shouldn't really get a shock from that fault - neutral in most houses is couples to earth at the head. The PSU should provide isolation anyway.

I'd get it checked by somebody competent :shrug:
 
Islander said:
You shouldn't really get a shock from that fault - neutral in most houses is couples to earth at the head. The PSU should provide isolation anyway.
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Yes, I know, but I can't think of anything else that would have shown the symptoms. If you have an RCD, putting live to earth should have tripped it immediately...
 
arad85 said:
Yes, I know, but I can't think of anything else that would have shown the symptoms. If you have an RCD, putting live to earth should have tripped it immediately...
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Or neutral to earth...

It's an odd fault. The first thing that came to mind was the backlight inverter shorting to the case but it doesn't seem that's likely.
 
ding76uk said:
Well I have been using paralells at work today:D

Just found out what it is. Bloody electrician has messed up putting in power to our wall mounted telly as you can feel the electric coming out of the wall to it, only discovered when turning mac off and felt all my arm hairs tingling. Changed plugs and presto no shocks and luckily for him one working mac with all backup drives fully functioning.

Electrician is about to get a nice call. Least mac is not messed up by it! Would have been more short and sweet if it was.
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A nice call - you are way to generous - he could have xxxxxxing killed somone - namely you
1. he shouldn't have screwed up
2. If he did some basic safety tests afterwards, he would have known
 
Well here is the next installment.

Electrician came today and tested everything. Works fine, not electric on the wall or anything, everything tripped fine, no readings out of normal, nothing. I also have had my Mac plugged into another socket in the same room and no static, no shock.

Obviously I don't want to risk anything by plugging my iMac back in, but I don.t want the cable trailing over my house when the plug near it is supposedly fine.

Anyone have any idea what this could be?
 
you mentioned a wall mounted telly. Did it by any chance include burying some cables in the wall and some plastering or filling in work? It just sounds like it might have been a dollop of damp plaster/filla touching a live terminal or a damaged positive wire. The moisture in the plaster is enough to allow electrical contact onto the wall or the metal plate of the socket, and then you get a shock much like severe static. When the plaster dries you no longer get the shocks as there's nothing to conduct the electricity.
 
Did the electrician stick a meter on the area of the imac screen you were receiving shocks from to check it for voltage?
 
Was the electrician that tested it the same one that installed it in the first place? If so, I'd get someone else to check in case the first one is a muppet. One of those voltage sensitive screwdrivers are handy to have. You can then check all round the case yourself.

If it only gives you a shock when plugged into particular outlet rather than all the time it rather points to that outlet being defective in some way.
 
srichards said:
Was the electrician that tested it the same one that installed it in the first place? If so, I'd get someone else to check in case the first one is a muppet. One of those voltage sensitive screwdrivers are handy to have. You can then check all round the case yourself.

If it only gives you a shock when plugged into particular outlet rather than all the time it rather points to that outlet being defective in some way.
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Don't use a neon screwdriver - those things are dangerous. They use your body to complete the circuit - a slight malfunction, damp or other problem could prove lethal.

The only safe way to test is with a proper meter and some expertise.
 
hepburn said:
you mentioned a wall mounted telly. Did it by any chance include burying some cables in the wall and some plastering or filling in work? It just sounds like it might have been a dollop of damp plaster/filla touching a live terminal or a damaged positive wire. The moisture in the plaster is enough to allow electrical contact onto the wall or the metal plate of the socket, and then you get a shock much like severe static. When the plaster dries you no longer get the shocks as there's nothing to conduct the electricity.
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I did bury the cables in but that was a month ago. The electrician tested using plug in meters and things, they came well recommended by several people. He checked everything. I plugged something in the plug but again it didn't repeat, and the mac is fine in the new plug.

Think I am going to have to plug mac back in and see what it was and whether if I do that it repeats. Going to leave backup drives well out of the way for the time being and see what happens.
 
It does sound like he tested the system properly. If you're still worried about things then do be very careful, keep one hand in your pocket at all times and only use the back of your hand to touch suspect areas and only lightly at that.

If you get a static shock then they tend to be sudden and very brief - the charge dissipates very quickly.
 
If you buried electrical cable in the wall, less than a certain amount (5cm depth if I remember correctly), there should have been capping over the cable, to protect it from drills (it should also mean that there was no wet plaster touching it).
If you did not do this, your electrician should not have signed off your work, as it shouldn't meet current building regulations.

If the electrician didn't do it when they just checked, you may wish to open the faceplates of the sockets, and check there is no discolouration in there, from sparking/bad connection.
(one of the circuits in my house, had had the earth cable cut out of a 2" segment, intentionally, it seems to stop arcing from tripping the MCB)
 
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Just to add that if you do decide to remove the sockets to check them, make sure you isolate them by switching the breaker off in the consumer unit first - then plug something in to check that it really is isolated.
 
coldpenguin said:
If you buried electrical cable in the wall, less than a certain amount (5cm depth if I remember correctly), there should have been capping over the cable, to protect it from drills (it should also mean that there was no wet plaster touching it).
If you did not do this, your electrician should not have signed off your work, as it shouldn't meet current building regulations.
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Is had a metal casing on it to protect it when it was installed. I will isolate it and check the wires. Is there a way I will be able to tell if something is up? What am I looking for in the discolouration, just a burnt type of colour?

Cheers for all the help everyone, it really is appreciated, I obviously don't want to fry my new Mac.
 
You mentioned an extension lead in post 1 - did the electrician test that in the wall socket when he came back?
 
ding76uk said:
Is had a metal casing on it to protect it when it was installed. I will isolate it and check the wires. Is there a way I will be able to tell if something is up? What am I looking for in the discolouration, just a burnt type of colour?

Cheers for all the help everyone, it really is appreciated, I obviously don't want to fry my new Mac.
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All you can really check for is noticeable darkening on the cables nearest the socket itself, that they aren't loose and check polarity i.e. live (brown or red depending on the age of the cable) to L, neutral (blue or black) to N, and green and yellow to earth.

If you do decide to check then after you've switched the breaker off, connect a lamp or something to the socket to make sure it really is isolated.
 
I may be way wrong here, but I'm pretty sure the iMac is not made of conductive material. Isn't it some sort of injection moulded plastic on the back of the display?
If so, then I would say you have a bad static build up from somewhere.
 
Johnny Thunder said:
I may be way wrong here, but I'm pretty sure the iMac is not made of conductive material. Isn't it some sort of injection moulded plastic on the back of the display?
If so, then I would say you have a bad static build up from somewhere.
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Older models had plastic back, newer ones are aluminium
 
I would still be amazed if this is any sort of mains problem.
The OP has a modern RCD protected installation, so assuming there are no major problems with the consumer unit, this would be a problem with the mac.
Any sort of fault which causes a shock would drop the RCD.
 
Johnny Thunder said:
I would still be amazed if this is any sort of mains problem.
The OP has a modern RCD protected installation, so assuming there are no major problems with the consumer unit, this would be a problem with the mac.
Any sort of fault which causes a shock would drop the RCD.
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Depends on how good the RCD is. Also, it depends on how large the ring main is (and whether it even has an RCD).
Also, if the earth wire isn't quite in, it is possible that the static could be being stored on the MAC, rather than the user.


As for checking, make sure that it is off, (use a lamp etc.), then release the faceplate. Make sure that there is no discolouration, then carefully with a (preferably insulated) screwdriver, gently move the wires going to the socket (try to only press on the insulated part of the wire for the moment), and make sure that they do not move within the screw holder. They should be tight within the screw-holder for each of the recepticles for the pins.
 
If a customer of mine contacted me after I had carried out a modification to their installation and reported they had suffered some sort of shock, then I would go through it with a fine toothed comb.
I am assuming the spark in question has done this and found no problems.

The earth can be disconnected, and the RCD will still drop. The RCD does not monitor the earth path. It checks that what is going out on the live conductor, is returning on the neutral conductor.




Carl, are you still getting shocks off it? If so, have you tried taking it to a friend, family or neighbour home and seeing if you still get shocks?
 
Johnny Thunder said:
If a customer of mine contacted me after I had carried out a modification to their installation and reported they had suffered some sort of shock, then I would go through it with a fine toothed comb.
I am assuming the spark in question has done this and found no problems.

The earth can be disconnected, and the RCD will still drop. The RCD does not monitor the earth path. It checks that what is going out on the live conductor, is returning on the neutral conductor.




Carl, are you still getting shocks off it? If so, have you tried taking it to a friend, family or neighbour home and seeing if you still get shocks?
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Hi John. I have it in another plug using the same extension lead and have had nothing off it and have had it running for 3 days now without being turned off.

The electrician using a thing along the line of the wire from the TV to the plug, then plugged some stuff into the plug, he didn't take it off though.

I'll have a look this weekend inside the plug. and see if anything is loose or disconnected and look for burn marks.
 
Carl, I am now assuming you can take a photograph of your consumer unit........;):)

If you can be arsed, stick a shot up of your ** mate.

It is a photography forum after all.:)
 
RCDs can develop faults - I've had to replace one on my ** myself. It does sound like the electrician tested the socket and lead correctly though and it probably was a static problem.

There would be a big difference between a shock caused by a static buildup discharging and a shock from a live/earth leak - a static discharge would be a single quick sharp shock whereas a shock from the mains would be constant.

I'm not advocating that anyone test this by deliberately allowing themselves to receive a shock by the way.

Electricity is dangerous mmmkay?
 
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