On 26-Feb-12 15:49, Roland Perry wrote:
In message , at 14:30:31 on Sun, 26 Feb
2012, Stephen Sprunk remarked:

The pumps had a sign suggesting that Electron card users put in at least
GBP 20 worth or else a larger amount of the balance on the associated
account would remain earmarked for a few days.

Sounds like they're authorizing the card for GBP 20, as discussed
elsewhere in this thread.

Not authorising, because that's "Electron" is a debit card on an account
which doesn't allow an overdraft. They will be deducting the £20
straight away, and allowing only up to £20 of fuel. If you buy less, it
sometimes takes a while for them to credit it you with the balance.

This may actually be an artifact of the authorization/posting separation
that you don't otherwise see.

It sounds like the pump is authorizing the card for GBP 20, so the
issuing bank puts a "hold" on GBP 20 in the account, reducing the
"available" but not "posted" balance. The bank may list this as a
"pending" transaction.

Then, at some point later, the transaction is actually posted by the
merchant, say for GBP 15, referencing the prior authorization for GBP
20. The "hold" for GBP 20 is removed and a debit of GBP 15 is posted to
your account.

It's possible that your bank records this scenario as two separate
transactions (a GBP 20 debit and a GBP 5 credit), but that's not how
it's "supposed" to work.

S

--
Stephen Sprunk "God does not play dice." --Albert Einstein
CCIE #3723 "God is an inveterate gambler, and He throws the
K5SSS dice at every possible opportunity." --Stephen Hawking