In article ,
Jeffrey J. Kosowsky wrote:
Someone told me that surge protection only *really* works when it is at
the Main panel.

- Is that true?

That statement is just TOO glib and simplified to be "true". What
seems reasonable: A surge protector in the main panel, with a good
connection to ground, is a very cost-effective first line of defense.
It might actually do all this is reasonably needed, excepting very
sensitive and very expensive equipment.

- Is it worth putting in when upgrading the main panel?

Given that it is quite cheap, and probably quite effective (assuming
you have a good ground at the main panel, without that it is probably
still somewhat effective), it seems to be a no-brainer to install it.

The ones that are easiest to install look like a 2-pole breaker, and
clip onto the distribution rails in the main panel like a breaker.
They have a ground/neutral pigtail hanging out, which you connect (via
the shortest possible path) to the ground/neutral bar. Remember, in
the main panel, ground and neutral are just about always bonded
together, with the main ground connected right there. We have a
Square D (I forget the model number) in our main panel.

- How much should it cost for a 200A supply?

That's a loaded question.

Let's look at one extreme: You have an existing main panel which has
spare space for the surge suppressor, and which has a really good
ground. You buy the surge suppressor at an electrical distributor,
through a drinking buddy who is an electrician and gets a good
discount. You install it yourself in 10 minutes. Total cost:
$50-$100 for the suppressor, and $3 for a beer for your buddy. Our
Square-D suppressor was about $70 plus tax, and I had left space for
it, and I know that there is an excellent ground right there.

Other extreme: Your main panel is stuffed to the hilt, so the surge
protector has to be in a separate box (requiring a hole to be drilled
in the main panel, and conduit fittings attached). There is no good
ground present (and never has been), and several grounding rods need
to be installed first; in extremely rocky ground this might require
trenching or drilling. And you don't want to do any of this yourself,
and hire an electrical contractor. As you should, you first pull a
building permit (in many jurisdictions, for example ours, a permit
would be required for this). At this point your are probably looking
at a few thousand $ (beginning with the permit fee of a few hundred
$), plus a visit from the building inspector. When the building
inspector comes by he finds that your whole electrical system is a
desaster waiting to happen (remember from above, it didn't have a good
ground either), and red-tags your house, causing the power company to
shut off power to you until you have the expensive contractor rewire
the whole thing. At which point you are better off mailing the keys
to the bank that holds the mortgage, declaring bankruptcy, and moving
to Canada.

[ For amusement, I can make the story a little nastier: Don't do like
a neighbor of ours did, when he had a "technical disagreement" with
the building inspector: He pulled out a loaded shotgun and pointed it
at the inspector. Good thing he didn't fire it. The building
inspector came back the next day, this time in the back seat of a
green car with blue lights on top, and two burly deputies in the front
seats. The relationship between applicant and building department
went down hill from there. ]

--
The address in the header is invalid for obvious reasons. Please
reconstruct the address from the information below (look for _).
Ralph Becker-Szendy