Surge voltage

[OK Sparky 93]

I am trying to be educated. Not sure if it is working.

I am not sure where it is sourced from, but everything I read tells me that 0-169 volts is, let’s say acceptable, and once it exceeds 169. Look out!

My question how is that 169 volts determined.

How did they come up with that number?

 

[ron]

For 120V surge protectors, the MCOV is the maximum rms voltage that may be continuously applied to the SPD (Surge Protection Device) for each connected mode.
Considering the regularly occurring transients that happen on the utility lines, many SPDs have an MCOV of 150V. That gives some headroom before the MOV would turn on and burn up if the overvoltage was sustained.

 

[Jraef]

When we say that a circuit is "120VAC", that is really "120V AC RMS", where RMS stands for "Root Mean Squared", a complex form of averaging of a moving value like a sine wave. The actual PEAK voltage is higher by the square root of 2, so 120VAC RMS = 120 x 1.41 = 169V Peak.