DC Switch Rating Confusion

[acoles1619]

Hey everyone,

Ok so here's the deal. I understand switch ratings for the most part, but I just can't figure this out. There is a consumer product that I own that uses a toggle switch to power the device on and off. The rating on the switch is 0.4 VA. This is the link to the exact switch. https://www.electro-tech-online.com/custompdfs/2010/08/gtogglesilluminated.pdf

Now the issue is that the product is used as a distribution box. You apply 12 volts at the input, and get 12 volts out at every output. It is poly fused at 6 amps total output. So it is possible to have 6 amps of current across this switch as I understand it. How is this possible? The unit is mass produced and has been in production for a few years, no one seems to have had any issues with the switch. Am I missing something here? Any input would be great. Thanks.

 

[OutToLunch]

It is likely just a logic level switch that is being used to drive/control larger devices that handle the loads.

 

[MrAl]

Hi,


Switches are rated in volts and amps. You have to have at least as high a voltage as your application can produce, and you have to have at least as much current rating as your load draws. Also, there are two different ratings for the switch, DC or AC. If you are using it in an AC application then you have to check the AC rating, and if DC then check the DC rating. These two ratings are usually different.
If the switch doesnt have a rating for DC or AC and you need that type, then you might have to look for another switch.

 

[acoles1619]

I really don't see how it could be a logic level switch. It's a power switch, it is connected directly inline with the power source which is a battery that outputs 16 volts DC. I understand that there are differences between AC and DC switches and the requirements for using them. Pretty much the function is this, you hook up the battery to the input, and use the toggle switch to allow voltage and current to flow to the outputs. It's a very basic setup. The switch is just really bothering me. It seems like it should not work in this application. Given the setup, doesn't the switch have the full 16 volts across it along with up to 6 amps of maximum current?

 

[crutschow]

It would appear that they are seriously overloading the switch, but apparently it tolerates the load.

 

[Mark_R]

Would you mind sharing what this "power distribution box" is used for? Just because it *can* pass 6 amps, doesn't mean it will in it's designed use. What is it designed to feed?

No matter what, the switch is only rated for 33mA at 12v, so yes, it's a poor choice if it's wired in series with the load.

EDIT: In fact, half of the switches capacity will be used just to switch the LED in the switch itself. That makes no sense whatsoever, you must be missing something. Are you sure there are no other switching components in there? (relay, mosfet, Etc.?)

 

[carmusic]

if it is really 6 amp that pass through the switch it would burn rapidly at 80 mohm contact! it is rated for 0.1A!! Im pretty sure that there is a relay contact (or mosfet, transistor) in parallel with the switch.

 

[acoles1619]

There is nothing else on the board. No relay or mosfet, nothing like that. The six outputs are used for equipment that draw anywhere from 170 mA to 1.2 A. I really don't see any way this switch should be working, but it is. A previous version of this product used a switch with gold contacts rated at 0.4va. This switch functioned without problems as well. I was hoping this would have been a simple thing I over looked but it appears to be defying the laws of electronics.

 

[OutToLunch]

do the loads reside on the board? how about a schematic? a picture? my guess is there is something there that you're not seeing or there is an incorrect assumption at work.

 

[acoles1619]

The loads are directly on the board. I will try to find a schematic, if not I can draw one up.