electric shock from outdoor security light

[aldo95]

I went to a job the other day to replace a security light. When i touched it i got a shock. After isolating the fitting, i removed the cover to have a look at the connections and all were securely in place. There was no water ingress inside the fitting either. I then removed the flex, turned on the power and checked to see if the flex had an earth. It did not. Can anyone think of a reason why i would get a shock? As i said before, all connections were tight and fully into the connector block and i also checked the halogen lamp connections at the lamp holder and they were fine. Any help about this would be great! THANKS

 

[AP Electrical]

Long shot,when the light was installed they havent damaged a wire from another circuit with lamp fixing?

 

[malcolmsanford]

We have this a lot out here in the middle east .....................where the earthing arrangements to say the least is poor, in many homes you will see a cable disappearing from a socket outlet to the nearest water pipe, to "earth" the plug.

This is normally done on either a piece of equipment that is faulty or in most of the cases a piece of old refrigeration equipment that the windings of the compressors are breaking down, not enough to cause a overload to trip the MCB, but enough to make the case a nice sensible tingle voltage ..............

So you are obviously making the path to earth when you touch the luminaire casing, and so there must be a reason that exposed conductive part of the fitting is LIVE. If there is no fault, or RCD protection then my guess is dampness, might be very slight, but enough to give you that nice wake up tingle.

Of course there maybe other ways, so over to someone else

 

[pushrod]

Do you mean it was a 2 core flex and a double insulated fitting or the supply wasn't earthed? Was the light working previously and was it working after you looked at it. Not that i have much idea at the moment tbh, but with more detail i or someone else might be able to suggest something.

 

[leolec]

How did you test the earth when you turned the flex back on?

 

[Dunc]

Was it fed off a socket circuit? If there was no earth continuity on a socket circuit and an appliance like a washing machine was plugged in you could get this issue due to capacitors inside the appliance dumping a voltage on to the earth. If there's no continuity all metal work on that circuit would have a voltage present on the CPC as it has nowhere to go.

 

[aldo95]

Long shot,when the light was installed they havent damaged a wire from another circuit with lamp fixing?

I don't think so as the bracket is screwed onto 14" thick sandstone, so i dobt i have damaged any cables behind the wall.

 

[leolec]

If you tested the earth by measuring the voltage between line and earth and the reading was zero then I would suspect the cpc is connected to line the other end, this is the only thing I can think of that would explain the shock

 

[aldo95]

Do you mean it was a 2 core flex and a double insulated fitting or the supply wasn't earthed? Was the light working previously and was it working after you looked at it. Not that i have much idea at the moment tbh, but with more detail i or someone else might be able to suggest something.

It's a three core flex and the supply wasn't earthed. The customer asked me to check it out as it wasn't coming on at night but this was due to the halogen lamp element broken. I have taken the light down till i find the problem

 

[aldo95]

If you tested the earth by measuring the voltage between line and earth and the reading was zero then I would suspect the cpc is connected to line the other end, this is the only thing I can think of that would explain the shock

Yeah, tested between line and earth and reading was zero. I will trace cable back to other end and see where it is connected into but i don't see any light switch to turn the light on and off. Maybe its coming straight off a wall socket or its a straight main from a lighting joint box.

 

[leolec]

Test the earth to neutral voltage - if that's 240 then cpc defo conected to line

 

[leolec]

Got to say that's not my preferred method to test circuits though!