whole house surge protector

• they have to be in the very first position
  • i.e. right beside the the panel main breaker switch
  • so you might have to move some wirs

The difference between the first and last position in terms of propogation of voltage is really very small. The speed of electricity assuming a 2' long back plane means that a surge propogates in about 2 nanoseconds. MOV’s typically have response times around 100 nanoseconds.

So, sure, put it at the top if you can, but practically speaking it’s about he same in either location.

The issue might be inductive reactance.  Inductance is likely in order of 300nH/ft.  It is not a lot but even the smallest reactance with thousands of amperes clamped (my Boltshields are rated 60kA each) will produce big voltage drop.  Sensitive circuitry powered closer to the power entry will see this as additional voltage on the top of already high clamping voltage.   Same goes for plain resistance of the copper bar in the panel.  Even if total resistance is in order of 10mohm it will produce 100V drop at 10kA current.  We're talking extremely short spikes (1-30us) of huge energy.  It is always good practice to place clamping device like MOV or TVS close to power entry.

This is so helpful and you guys are great!  I will tell my electrician to go ahead with whole house surge protector.

Thank you!

Margot

RE: protector placement - I was just quoting the installation instructoins that came with the unit. But the electrician told me this also

I assume the manufacturer knows what they are talking about🤔

Ans since we all follow the installation insrtuctions - I thought it best ot point it out😏

Regards - Steve

Just do it!

Had my whole panel replaced with dedicated circuits for audio gear but the first thing I arranged was a whole house Siemens surge protector.