10ax switch?

[sunbeam37]

I want to replace a light switch in the garage that controls a 100w incandescent bulb. Do I need to use a 10AX switch? The garage lighting circuit also contains 2 other 100w bulbs and 2 fluorescent lights all of which have their own switches that I am not replacing.
Thanks for any help.

 

[JohnD]

Short answer: Yes use an ordinary light switch which will be rated at 10A


(edited to remove errors)

 

[JohnW2]

Short answer: Yes use an ordinary light switch which will be rated at 10A (I don't know what your "x" means)

It's not "his x", "10AX" is a universal descriptor of such switches. IIRC, the "X" means that the 10A rating applies to both inductive and resistive loads.

Kind Regards, John

 

[JohnW2]

deleted - quoted instead of edited, yet again!

 

[JohnD]

oh dear

so it is

 

[sunbeam37]

Thanks to both Johns for your help.

 

[winston1]

FYI a 100W lamp uses 0.4 amps so a 6A MCB can supply 144 of them, which is much more than you will ever need, and a 10A switch is ample.

But you would never be able to switch them on as the cold starting current is a factor of several times that amount.

 

[JohnD]

don't care. nobody uses 100W incandescents any more, and nobody has 144 of them.

Though funnily enough, years ago we briefly used Type D MCBs for theatre lamps because of cold-start surge. Then reconfigured the dimmer packs and went to C. There must have been a design error as they were not supposed to cold start.

now they're LEDs with DMX control and you could almost run them off a torch battery.

 

[bernardgreen]

144 lamps would use (1440W divided by 240v) = 6A, near enough

Except when switched on from cold. The cold filaments would have a lower resistance than when they were hot so until the filaments are white hot the current would be higher than the 6 amps. If the lighting load is close to the MCB rating then a slow to operate MCB is needed or a staggered switch on sequence is necessary to avoid nuscience trips

 

[JohnW2]

FYI a 100W lamp uses 0.4 amps so a 6A MCB can supply 144 of them ...

6 divided by 0.4 used to be 15, not 144.

So a 100W lamp uses (240v x 0.4A), near enough ... 144 lamps would use (1440W divided by 240v) = 6A, near enough (edited to remove error)

Same error (despite your edit). 144 lamps would use 14400/240 = 60A.

Kind Regards, John

 

[EFLImpudence]

A gross mistake

 

[Echo the husky]

A gross mistake

Yes you won't get much work wiring domestic lighting circuits in 10.0mm² T+E!

I was taught at college the general rule was 12 fittings per 5A circuit, which allowed 100W per lighting point. Back when we wired pendants in each room, a batten holder in the bathroom and a fluorescent batten in the kitchen. How times have changed.

 

[ban-all-sheds]

6 divided by 0.4 used to be 15, not 144.

I blame the USA.

 

[Echo the husky]

I blame the USA.

That reminded me of this.

 

[sunbeam37]

I've just found out that the 1gang 1 way garage switch I wish to replace has 2 cables entering the switch box, I was expecting 1. One of the cables only seems to have a red wire coming out of it and is connected to the bottom of the switch, the other has an earth wire and a red wire connected to the top of the switch. Why are there no neutral wires?
Also instead of just replacing the old switch I wanted to extend the cable further up the garage to the new switch for convenience. I intended to put a 20 amp junction box where the old switch is and new cable from the box to the new switch. Inthe junction box is it ok to connect the new T&E blue wire to one of the old red wires, and the new brown wire to the other red wire, and the new earth to the old earth wire? Then the new blue and brown wires to the bottom and top connectors in the new switch. I don't know much about electrics so maybe that's all wrong. Would value any help.