Re: Tamper Contacts

["Frank Olson" <Please-use-the-email-links@xxxxxxxxxxxxxxxxxxxxxx>]

"Will" <DELETE_westes@xxxxxxxxxxxxxxxxxx> wrote in message
news:3vKdnTovqc_aQ8zeRVn-rA@xxxxxxxxxxxxxxx
> We are commercial not residential.  I'm inferring this from your
> description:  the purpose of the tamper is to determine if someone has cut
> wires while the alarm system is disabled?

That's only part of the reason to use it.  A dishonest employee could very
easily remove the cover from a motion sensor and wad it with toilet paper
(I've seen that done) so it won't sense anything.  In this instance,
employing the tamper would alert the CS who would in turn notify the
customer.


>
> If someone cuts the wire without the tamper wire in place, won't the panel
> sense this by some other means?

Sometimes.  If, for instance, end-of-line resistors are properly placed (at
the motion sensor for instance), then either a "fault" or "trouble" will
show up at the keypad preventing the end-user from arming the system until
the problem is repaired.  If, in the process of cutting the wire, the power
supply is also shorted out, then all the keypads in the system will become
inactive and a call for service will go out to the installing company.
However, if end-of-line resistors aren't used and the power supply is only
momentarily shorted (the panel employs MOV's or an automatically resettable
circuit breaker), then you could wind up with a short across the alarm
terminals.  The panel would never "see" an alarm from that zone and you
would have no way of determining at the keypad that something was amiss.


> On an Ademco 128BP, there would be no
> message on the panel?

Depends.  See above.


>
> What if someone cuts the wire while the system is enabled?   Does tamper
> help in this case?

If they happen to "cut the wire" on a system that doesn't employ properly
installed end-of-lines, and they happen to also *short* the alarm terminals
at the same time (or within the pre-determined alarm time threshold which is
usually in milli-seconds), then you're "SOL".  Chances are though, that if
someone deliberately cuts the wire on an *armed* system, the siren's going
to be going (unelss the zone's bypassed).

Bottom line - On commercial installations always use end-of-line resistors.
Use door and window contacts with built-in end-of-lines of the correct value
for the panel (these can be ordered through most alarm companies).  And
*always* utilize devices with built in tampers.