CHAPDISC: DH3, The Dursleys Departing

[Carol]

No: HPFGUIDX 177371

kneazlecat54 wrote:
> > <snip>
> > > Hestia tells Harry that Mad-Eye will give him the details, but
that the Dursleys must leave so that they will be far enough away to
Disapparate at the same moment that Harry leaves Privet Drive for
> > good, thus breaking the protective enchantment that Lily gave him.
> > <snip>
> > 
> > Carol responds:
> > <snip> Ihope you don't mind my pointing out here that the 
> protective enchantment that's ending is Dumbledore's, which was 
> based on Lily's blood protection. <snip> 
> 
> Laura:
> Really?  So the same protection wouldn't come into effect any time a 
> parent sacrificed him or herself for a child in the WW?

Carol:

Help. Let me see if I can clarify here. The blood protection that
*Lily* provided came about because she had a chance to live but chose
to die instead, apparently a unique occurrence in the WW until Harry's
choice to sacrifice himself in some ways replicates it. *That*
protection continues into the fight with Voldemort through the drop of
Harry's protected blood in Voldemort's veins that enables the soulbit
in the scar to be destroyed without killing Harry.

But the blood protection that *Dumbledore* placed on 4 Privet Drive is
different, based on Lily's sacrifice but using her blood connection
with Petunia to protect Harry. Essentially, Petunia sealed a magical
pact by taking Harry in. As long as Harry can call 4 Privet Drive
home, *there* (and only there) he cannot be harmed. *That's* the
protection that expires when Harry turns seventeen.

So, exactly. "The same protection wouldn't come into effect any time a
parent sacrificed him or herself for a child in the WW." Protection
like *Lily's* only came about because she had a choice to live and
chose to die instead. *That's* why the Killing Curse backfired for the
only time in WW history (until the plot arc comes full circle in "The
Flaw in the Plan"). But the additional protection provided by Harry's
staying with his sister's "blood" (Petunia) occurred because of an
additional protective charm placed by Dumbledore.

Carol, who can find the canon if necessary to clarify the distinction
between the blood protection placed by DD on Privet Drive and the
original protection provided by Lily's sacrifice, which DD's spell
builds on and extends