All low-voltage systems, one contractor

All six are with us — the scope list above sets them out item by item. One contract, one site manager, one acceptance test.

We also write down what falls outside scope — items such as civil works, conduit chasing and painting usually sit with the site's own contractor. Rather than hiding these behind "not included" in the quote, we list them as a separate line.

We survey first. Cabling category and run lengths, the location and spare capacity of existing panels, the brand and firmware version of the panel/recorder in use, the power and cooling condition of the system room. Whatever is usable stays.

The typical outcome is a mix: the backbone and conduit infrastructure is kept, endpoints and central devices are renewed. A from-zero build is recommended only when the existing infrastructure cannot carry what the target system needs, and the reasoning is written into the quote.

Floor area on its own is misleading — two facilities of the same size can come out many times apart depending on point density. In order:

• Number of points — cameras, card readers, speakers, outlets, detectors.
• Cable route difficulty — in an existing building, the condition of suspended ceilings, conduit and risers; in a new building this item is almost absent.
• System class — camera resolution and recording duration, whether access control includes biometrics, whether the announcement system needs evacuation certification.
• Depth of integration — whether the systems trigger each other.
• Commissioning and training — the item most quotes forget, and the one that takes the most time on site.

Brand choice is usually secondary next to these five items.

Most of the installation is done while the facility is running. The steps that require a shutdown are known and few: panel connections, the cutover moment from the old system to the new one, and acceptance tests. We schedule these between shifts, on a weekend, or during a planned stoppage.

We provide, in writing, before work starts, which step requires how much downtime — the schedule comes as an appendix to the quote. The total commissioning time varies with the size of the project.

This is where integration is actually tested. The typical scenario: when a fire alarm triggers, the access control doors on the escape route release, the announcement system delivers the evacuation message to the relevant zone, and the cameras flag the event and tag the recording.

For this to work, three things are needed: the systems speaking a common protocol, the scenario written down on paper in advance, and each step tested individually at acceptance. And a shared time reference — for logs to be correlated, all the systems need to see the same clock, which is exactly why master clock is on this list.