Edison screw lamp - i received electric shock!!

[Column79]

I went to change the bulb on my mums reading lamp and when I tried to remove the bulb (Edison Screw) I received an electric shock even though the s/w was in the off position. I have a LV3 cert in electrical technical but I lack experience as I own mine own landscape business so it has been a while since I did something electrical.

If my memory serves me well (i did get distinctions! ) It is probably a polarity issue. The metal screw itself forms the contacts for the circuit. If it isn't wired correctly or if the plug outlet is non-polarized the metal screw can become energised which can, well it does, present a shock hazard to anyone changing the bulb. The NEUTRAL should be connected to the thread and the LIVE to the center pin or terminal. But the thing that is confusing me is it is just a reading lamp bought from a shop so i think the problem must be coming from socket outlet itself.

I guess these are the couple of questions I need to get an answer too:

1)I'm going to isolate the circuit before i visually inspect it but what might I find? Do i expect to see the LIVE and NEUTRAL in the socket outlet to be terminated in the wrong terminals? If so, I guess it is just a quick case of rearrange them?

2)If the LIVE and NEUTRAL are in the correct terminals I guess i would have to inspect the plug of the lamp itself. Which surely can't be the case as it is pretty much new, as far as I know?

3)Should i carry out a polarity test of the ring and thus go through continuity and insulation resistance as well if:

a) It is neither of the above two questions and the LIVE and NEUTRAL have been terminated correctly

b)Or, if it is the LIVE and NEUTRAL conductors, and they have been terminated incorrectly,, and a I rearrange them, is it advisable to still carry out a continuity test, insulation resistance test and a polarity as well just to be on the safe side?

I ask because i just feel a bit under confident about going ahead with it as i don't want to burn the house down! I have knowledge but just haven't applied it in a while.

If you can help I'd really appreciate it.

Thanks,

Regards Column79

 

[Stroppy]

Would be very easy to test the light for correct polarity with a meter or anything that shows continuity. One probe on the edison outer screw, one on the plug's Live pin. If you have continuity with switch either way = wrong polarity! Socket&see the socket, and get a sparks in if necessary.

 

[Column79]

Thanks for the reply


No I haven't mate

 

[trev]

I'm a little worried by you changing over the L & Ns at a socket outlet mate. What was the reason for you doing this? Did you remove the face and see that the terminations were wrong or did you have some other justification for doing this?
I don't want to sound like I'm having a pop at you because that's not my intention.

 

[Column79]

I'm a little worried by you changing over the L & Ns at a socket outlet mate. What was the reason for you doing this? Did you remove the face and see that the terminations were wrong or did you have some other justification for doing this?
I don't want to sound like I'm having a pop at you because that's not my intention.

The wiring in plug was fine but the s/w was off and i got a shock. I've isolated the supply and visually verified the core colours at the terminations. The neutral is in the s/w line. What I wasn't sure about was if after changing them back round would i have to do a continuity test on the whole ring again, and then insulation resistance test followed by the polarity. I suppose i would have to because other sockets on the ring might be non-polarized as well.

 

[trev]

I'd be looking at the full range of tests on that RFC mate as a matter of urgency.

 

[ayjay]

trev i don,t know why you post/respond on these threads
the poster is an idiot

 

[Column79]

The only idiot here is then one who cant read then thread properly

Now if you don't mind, **** off.

 

[Column79]

Thank mate but got someone coming round to have a look. I was just trying to remember some of the stuff I did at college. I don't think I'm that far off. I think avjay likes to think its all rocket science. Maybe it was for him

 

[markc123]

Well that took an unexpected twist!

 

[DPG]

trev i don,t know why you post/respond on these threads
the poster is an idiot

Ayjay, you are one of the reasons this forum is going downhill in my opinion (which may not count for anything). When you went out the door the other week, was it a revolving one? Apologies for the negative post. Daz