Hello again,
In reference to posts 8, 9, and 10 by Eric and Roman here's my take after reading other posts here too...
The rating:
"5A. 14VT"
means the switch will operate just fine with a bulb that has a tungsten filament that draws 5 amps or less and at a voltage 14 volts or less, and that's all we have to know. By trying to specify whether or not that 5 amps is the "break current" or the "normal operating current" is futile because they are both the same, which would be 5 amps (max). So specifying either should be ok, knowing that the other is the same. I took it to mean the "normal operating current" but Eric's interpretation as the "break current" is equally valid.
We dont really have to think about the surge current, knowing it will be around 10 times higher for a tungsten bulb but will last only a short time.
So to put this into an application, with a switch rated 5 amps 14 VT or as pointed out by jpanhalt 5 A 14 V(T), that means we can go out and buy a 14 volt tungsten filament bulb that draws 5 amps nominally and expect reasonable life from the switch. That's as simple as it gets
There's still a little question however as to whether or not this works with DC as well as AC. But as one poster pointed out this rating of 14VT means either AC or DC. I do have to still wonder how well this would work with an inductive load like a motor however, where we break the current and there could be a voltage spike of very high value. Im thinking maybe some kind of snubber to keep the voltage a bit lower to protect the contacts. I think all switches have to 'wipe' at least a little though right?
I am glad i brought this up here. Looking on the web i dont see anything about this kind of rating. I see it in data sheets in different places, but not any clear description except of course for right here
AFTER reading this thread however, looking up "Switch Tungsten Ratings" turns up some very useful and interesting information:
To re-rate the switch of 125vac 1 amp for 12vdc for example i find the new ratings would be:
Resistive load: 1.25 amps
Inductive load: 1 amps
Lamp load: 0.31 amps
Motor load: 0.41 amps
Capacitive load: 0.31 amps
Where they got these numbers from i dont know so it is hard to judge the accuracy. Using this information for the original switch quoted in this thread, the rating is 125vac at 13 amps, so at 12vdc it should handle a motor load of:
13*0.41=5.33 amps.