Homemade lamp and dimmer short


  #1  
Old 01-05-16, 01:11 AM
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Homemade lamp and dimmer short

Hi,

I'm building my third "pipe" lamp and when I was doing final testing yesterday before closing it up, it shorted and blew the main fuses (outside my apartment) so a pretty big short circuit... I triple checked for shorts and I also test on each stage of the build so I am really confused what happened. I drew a crude diagram of the wiring below.

I have 4 lamps connected in parallel and a dimmer rated at 250v, 3 amps, lamps draw max 1.8 amps and there was only one bulb connected. The dimmer blew but the bulb did not so the short must have happened before in the circuit.

Things I'm considering:
There was no ground - something I will do immediately for safety from now on.
I do not know if dimmer was connected on the live or neutral - ebay seller now tells me it "must" be connected on the live - I could have flipped the plug either way.

Dimmer is mark with D, yellow circle is where the connector is.
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Dimmer I used:
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  #2  
Old 01-05-16, 02:16 AM
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If you have not been welcomed to our forums.....welcome!
I would suggest that you go back and fill in your location in your forum profile.
If you are in Europe as I believe you are it would have a bearing on answers to your questions.

Although you should install the dimmer according to mfr's instructions it does not matter electrically which way you connect it on an AC power supply.
If the dimmer was damaged by an electrical short then the problem is either the wrong dimmer or an electrical short downstream of it.
Likely a pinched wire or bad connection on the lamp holders......maybe a forgotten insulator sleeve on the dimmer itself or on the lamp sockets?
 
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Old 01-05-16, 04:03 AM
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Thanks Greg
I am in Europe, yes. I though that it would not matter whether the switch is on the live or neutral that's why I didn't pay attention to that, just wanted to confirm since I just couldn't figure out what went wrong. I have used the same type of dimmer before with no issues... just have to be even more careful I guess.
I have another issue - I don't think that I have a "ground" wire coming from the ceiling - is it "legal" to ground the lamp from its metal body to the neutral wire from the wall.. probably not the best idea?
 
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Old 01-05-16, 07:39 AM
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s it "legal" to ground the lamp from its metal body to the neutral wire from the wall.
Never!. It can put dangerous current on any metal bodied grounded appliance or device.
I though that it would not matter whether the switch is on the live or neutral
Wrong. The neutral should never be switched. Further the neutral must always connect to the screw shell not the tab at the bottom of the socket if you are using screw base bulbs. If you are in the UK the plug should have an appropriate size fuse in it.
 
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Old 01-07-16, 02:04 AM
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Thanks Ray,

I will keep that in mind going forward. Can the neutral being switched or being connected to the tab of the bulb socket, cause a short... I don't see how but I am not an expert obviously.
 
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Old 01-07-16, 03:56 AM
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No, just unsafe. .
 
 

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