Sir – It appears that the National Security Inspectorate (and others, I hasten to add) are telling installers that only Grade 3 protection intruder alarm systems are those with dual path.

This is largely because security installers will not bring to the attention of end users the statement requirement published as part of DD243.

That statement reads as follows: “Important: Your attention is drawn to the fact that failure or compromise of single path signalling cannot be passed to the police. While the system failure persists, subsequent alarms cannot be signalled to the Alarm Receiving Centre and then passed on to the police service.”

Kept in the dark, end users are purchasing systems that are more expensive than need be the case. Grade 3 can be achieved without costly dual path, and in truth is only necessary if sites are at high risk from a line fault/line cut. In other words, a perceived risk rather than a reality. Even a Grade 4 system can be single path if it boasts additional warning devices.

The EN Standards have been written to ensure that an intrusion is detected, or similarly any apparent failure in the communications path. They were not written to drive everyone towards dual path.

The grading of a system is driven by the lowest component – this may be a PIR or any number of things. The alarm transmission medium is but one factor.

In effect, this could drive 400K systems operating on redcare to be upgraded to GSM or DualCom at vast cost to the client without any good reason as to why.

Letter sent via e-mail, name and address supplied

Source

SMT

Postscript

The Editor replies: Installers now take liability for the systems they install. It makes good sense to use dual path signalling for Grade 3 systems. Indeed, many responsible security