Which push button ratings should be considered due to its datasheet?

Question

I'm planning to use this normally on push-button switch According to the datasheet it says:

Contact Current Rating: 650 mA @ 30 V dc

But in my application the button will be pushed less than a second where the voltage across it will be 48 V and the current through it will be 48 mA for less than a second.

Should I look at the power (P = IV = 30*0.65) in this case, or I shouldn't use it since it says 30 V in its ratings?

Push-button controls 48 V supply and is normally open. Here is the part of the circuit where the switch is in LTspice(I didn't check this in scope):

Points A and B represents the terminals of the push-button. Below green plot is the potential difference across the switch terminals A and B:

And the blue plot below is the current through the switch:

And finally, I zoom to see both the voltage across the switch and the current through the switch:

What I understand from the above plots, the switch is exposed to 48 V whenever it remains open. The moment the switch is closed, the potential difference drops quickly in nanoseconds to zero volts and micro-ampere level current passes through it.

What I understand from the first answers is that, the problem with this push button is that if I use them in my circuit, they will be exposed to 48 V all the time when the switch is normally open. So the real problem does not occur the moment I push the button but it occurs when the push button is not pushed at all.

Is that correct?

Answer 1

Arcing distance is determined by the voltage. Since the voltage in use is higher than the rating, either the switch may become damaged over time due to the contacts either eroding away or welding closed, or opening the switch may not reliably break the connection since arcing will occur.

Answer 2

A rating of "650 mA @ 30 V dc" is just a shorthand notation that tells you that the contacts can handle at most 650 mA when closed and at most 30 V when open. If you violate either of these specifications at any time, you have exceeded the ratings of the switch.

Multiplying the numbers together is completely useless.

Answer 3

The reason the DC voltage ratings are so much lower then the AC ones is that a DC arc will not self quench, and 48V is more then high enough to sustain an arc across typical switch contact gaps if there is enough current flowing.

You want a switch rated for more then 48mA AND more then 48V DC, either one on its own will not really suffice.

Of course you could try to qualify a switch for operation outside the datasheet ratings, but you are pretty much on your own at that point (With your very current limited load, and the modest overvoltage) I might try it if reliability and cycle life did not need to be very extreme, but it is not something I would do in a production product.