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In-Line Switch Wiring

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In-Line Switch Wiring

Just bought an "anglepoise" type desk lamp from Asda... (£17.00)..... the lead was not long enough, so I re-cycled the lead off my old desk lamp....
To make a "safe" connection, I decided to do it inside the in-line switch .... then noticed that the switch was actually wired across the BLUE wire....
Am I correct in thinking this is "not correct" ?  and it should be wired across the BROWN (live) wire? 
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Re: In-Line Switch Wiring

Is it the halogen type with a transformer or a standard mains one?
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Re: In-Line Switch Wiring

Standard mains.... uses E14 halogen candle bulb.... no transformer involved.
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Re: In-Line Switch Wiring

Make sure the plug is wired correctly as well, but yes it should be on the LIVE Brown wire.
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Re: In-Line Switch Wiring

I thought so.! ! .... good point about the plug wiring..... my replacement plug is wired correctly.... brown to fuse.... however... just checked the wiring on the original, and the live wire was the BLUE wire...    Shocked 
it is a moulded plug.... so had to check it out with the ohm meter...
I think I will write to ASDA and let them know about it...  !
Midnight_Caller
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Re: In-Line Switch Wiring

Did it have the kitemark or CE Mark?
[quote="BBC"]
In the UK, standards are regulated by the British Standards Institution (BSI). Products which meet these standards can be marked with the KiteMark.
There are also separate standards for the European Union. If a product meets these, it can be given a CE Mark. The marks show government officials that the product conforms to a standard, which enables it to be legally placed on the market within their country.

[Edit] Added some more info
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Re: In-Line Switch Wiring

Technically to conform to all the right standards it should be on the brown but it's AC anyway so it really makes absolutely no difference.
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Re: In-Line Switch Wiring

Not really as the N line can sometimes be tied to the E line. The L connection should always be switched. Since the blue was connected to the L it was switched correctly if all be it wired wrongly.
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Re: In-Line Switch Wiring

The colour of the wires makes no difference to the functionality BUT if neutral is switched instead of live then the lampholder remains live when switched off, even with an E14 (small Edison screw) it's too easy to stick your fingers into the fitting if you remove the bulb.  Also the live should be the bottom contact in the lampholder as this is more difficult to reach than the side contact.
If the plug got broken and someone replaced it following the correct wiring standards (brown-live / blue neutral) then this could be potentially very dangerous.
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Re: In-Line Switch Wiring

Quote from: w23
if neutral is switched instead of live then the lampholder remains live when switched off

And assuming that the neutral isn't earthed as HmB has said, it would still remain live even if the live was switched because the neutral would be carrying AC too.
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Re: In-Line Switch Wiring

The Neutral should always be <<50V if measured against earth, the live carries a nominal 230V (measured to neutral, so also roughly 230V to earth).
Call me 'w23'
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Re: In-Line Switch Wiring

Yes, it does have the CE mark on it.... I think the switch also had a kite mark on it... ( I have stuck it down to the base with araldite, for convenience, so can`t double check it now ! ! )...
There is no "Earth" connection ( only two wires Blue and Brown)...  The plug is fused.
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Re: In-Line Switch Wiring

Which CE mark does it have?

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Re: In-Line Switch Wiring

As above - live should always be switched and you can also switch both live and neutral if you have a double pole switch.
The neutral wire if you touched it by accident would not kill you or even give you a shock in 99.999% of the time but the live will always be potentially fatal.
Imagine if you came across a person being electrocuted and you turned the switch off. You'd naturally assume that by removing the power to the item (which would now appear dead) that you would not get a shock from touching the said person/appliance but if isolating the neutral instead of the live had been performed then you too could end up getting electrocuted.
Take another scenario : You have an unearthed badly wired metal desklight. The live wire goes through straight to one contact of the bulb. The other contact goes to the metal case and the neutral wire to the plug. Don't laugh - I've seen this happen.
With no bulb in, nothing is live
With the bulb in, the neutral wire brings the potential of the case back down to zero.
With the bulb in and the neutral wire disconnected, the case of the lamp is at the full 240 volts !
An extreme example but a company I once worked for had a similar scenario when they made a slight modification to a product which meant when the item was "off" there was a readily touchable 240v live metal part sticking out of it ......
This is also the reason that at your fuse box, the fuses are *always* inline with the live wire.
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Re: In-Line Switch Wiring

Quite a few years ago a neighbour brought round a non-functioning heated roller set for curling hair.
I took the cover off the plug and all was correct in there, red - live, black - neutral and green - earth.
When I took the bottom off the unit the connector inside was wired red - earth, green - live and black - neutral with the switch downstream of this connector making the whole unit live as soon as it was plugged in.
Fortunately all they had done was plug it in and switch it on with the insulated control.
I rewired and returned it telling them of their near miss.

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