UKC

Hi. Anyone know what amps I need? For a floor lamp.

Seems most switches are 6amp but some are 2 amp. 

Divide the Wattage of the lamp by 230.
6 Amps is enormous for a lamp!

Only you can say and it will depend on the current protection of the circuit/ device. If it is plugin, then check the fuse in the plug.  You need to use a switch with a higher rating then the fuse.

Put a 1A fuse in the plug and buy the switch you like.

jk

It depends on the power consumption of bulb, and you can work it out yourself. Amps equals watts divided by volts. UK domestic voltage is 240V. So if your lamp has eg. a 60W bulb then the current flowing will be 60/240 = 0.25A.

choose the switch that looks safeest and well made, to standards, and fits any aesthetic considerations you have

I know from personal experience that these switches are best not operated with wet hands!

My first memory is of unscrewing one of these switches when I was young enough to be in bed with both of my parents and of the electric SHOCK! I got.

That is poor advice.  Fit components that are rated for the highest possible fault current; NOT the operating current.  In practice, this means referring to the circuit protection rather than the appliance.

I've had a quick look at this, and, on a 6A MCB you're looking at a minimum fault current of around 35A.
In practice that is really low.  Even so, a fault current of that order would take out a 3A BS1352 fuse in under 0.02 seconds. Specified disconnection time is 0.4 seconds. A 2A switch would laugh in the face of that. >35A the fuse would operate virtually instantaneously.

Remember the current rating of electrical equipment is the maximum current for continuous use, not under fault conditions.

When you say minimum fault I presume you mean the minimum short-circuit current.  In reality, a fault current can be any value (even less than the normal current) depending on the impedance of the fault circuit.  When you design a circuit, you have to consider the worst case scenario i.e. a fault current that is just less than the operating current of the circuit protection.  You make sure that all components can take a current a little higher than the rating on the fuse (or MCB) without setting your house on fire.  That's what I do anyway.

2 amp will be fine. 

I think you mean the highest current that could possibly be drawn without operating the circuit protection (which in this case will be the fuse in the 13A plug). The maximum prospective fault current will be somewhat higher than what the circuit is protected at.

Thanks.  Yes, that was what I meant.

So, as JKarren said above, the correct fuse to put in the plug would be 1amp, meaning the 2amp switch is perfectly fine.  Probably a 3 amp fuse would also be fine in reality as a 2 amp switch would have a safety margin.  

I don't really understand why it need be any more complicated than that.  Nor was the advice given above wrong.  

I was criticising advice (from a couple of people) to rate the switch based on the expected draw of the appliance, which is dangerous (all else being left the same).  As you say, if you modify the circuit protection to suit the switch then you are effectively doing the same as I suggested.  If that suggestion had been part of the answer, then I wouldn't have bothered replying.  

I think you already know the answer to that.
He's a bloke on UKC imparting his expert advice.
Enough said...