A specific reply from JimB .. .. ..
The scope used to take that picture of the relay back EMF was an Agilent DSO3202A, a fairly new digital storage oscilloscope which is a bit beyond the price range which we are discussing here.
The vertical sensitivity ranges of that scope are switch selectable from 2mV to 5V per division.
If you look at the relay picture, you will see that there are eight major divisions on the vertical axis.
Also on that picture you will see that it is annotated CH1 50V/div at the bottom left hand corner.
In the set-up menu for the vertical axis, there is a place to manually set the division ratio of the probe which you are using, in this case I was using a X10 probe which made the 5V/div range into a 50V/div range.
Looking at my much older Telequipment D75 scope, the vertical axis scaling is from 5mV to 20V per division.
Using a X10 probe with that, you would have to look at the range switch, look at the probe and do a bit of mental arithmatic to arrive at 200V/div.
When you say:
However, I've been looking at spec's and they all seem to have a quoted voltage range way below such a voltage spike.
I guess that you are looking at the "Volts per division" and forgetting that there are probably eight or ten divisions, and that it is good practice to use a X10 divider probe for most measurements.
Why is it good practice to use a divider probe?
Expanding on what KISS says above...
The input impedance of 99.99% of all scopes is 1Meg Ohms with some value of capacitance in parallel, typically 20 to 30pF depending on the scope.
Using a length of screened cable or coax cable to connect the scope to the circuit under test will only increase the capacitance, and depending on what type of circuit you are connected to, the extra capacitance, and sometimes the 1Meg Ohm resistance can affect the circuit operation.
Using a X10 divider probe will increase the resistance to 10Meg Ohm and reduce the capacitance (theoretically) to 2 to 3pF. I practice the capacitance will be higher, but still generally less that 10pF.
JimB