Why supply and install
It is a fair question, and it is usually asked for good reasons. The answer has less to do with the installation than with who is standing in the kitchen in year three.
The question comes up early, usually from a builder, and almost always in the same words: could you just supply the equipment and let our electrician install it?
It is a reasonable question. The electrician is already on site. They are already pulling cable. Adding a few more terminations looks like the efficient answer, and on a conventional job it often would be.
Baillie works on a supply and install basis, and it is worth setting out why, because the reasoning is practical rather than territorial.
The install is not the part that is hard
Mounting a keypad is not difficult. Neither is terminating a data point or hanging a speaker. A good electrician does all of that to a higher standard than most people would manage.
What takes the time is everything around it.
A system is not a box of equipment. It is a set of decisions, most of which are invisible once the walls are closed: which cable goes to which position and why, what the rack has to accommodate in three years, how the lighting panel is addressed, which circuit belongs to which scene, where the heat goes. Those decisions were made during design, and the person installing has to carry them accurately through to the wall.
Hand the equipment over and the decisions go with it, uncommunicated. The install becomes a reconstruction, and the reconstruction is usually close but not exact. Close is enough for a light to come on. It is not enough for a scene to be right.
Two trades, two scopes, one site
None of this means replacing the electrician. The electrician's scope stays the electrician's.
On a typical Baillie project the electrical contractor runs the cable at prewire to a documented schedule, prewires, cuts out and fits off the lighting side, and does the switchboard work. Baillie documents the positions and the cable types, builds and commissions the control side, cuts out and fits off the technology devices, and proves the whole thing works.
Where the line falls varies by discipline, and it is written down before anyone is on site. The lighting panel is designed and commissioned by Baillie while the electrician prewires and fits off. Ceiling speakers run the other way: documented by Baillie, cabled by the electrician at prewire, then cut out, fitted and commissioned by Baillie so levels are set in the finished room.
Two trades, working to one set of drawings, each doing the part they do best.
The factory is the reason it works on site
The part that makes this practical is that most of the installation does not happen in the house at all.
The rack is built at the studio. Every device is mounted, cabled, labelled, programmed and run as a complete system on the bench, for days, before it goes anywhere near the home. Faults get found at a workbench, where they cost an hour, rather than on site, where they cost a trade visit, a return booking and a client watching someone kneel in front of a cupboard.
By the time Baillie arrives for fit-off, the system already works. The site visit is short and clean, which is the outcome the builder actually wants, and it is only possible because the same party that designed it built it.
Supply only inverts that. The equipment arrives in boxes, the configuration happens on site, and the fortnight the builder was trying to avoid happens anyway, at the worst point in the programme.
Who the client rings in year three
This is the part that decides it.
A home automation system is not finished at handover. It gets added to, it gets firmware updates, it develops the small faults every system develops, and somebody has to answer the phone.
With supply and install, that is one number. The studio designed it, built it, commissioned it and documented it, so a call can usually be resolved by someone logging in remotely and looking at the same system the client is standing in front of.
With supply only, the question of who owns a fault has no clean answer. The integrator did not install it. The electrician did not design or program it. The client is in the middle of a conversation between two parties who each have a reasonable account of why it is the other one's problem. That conversation is unpleasant for everyone, and it tends to happen at the least convenient moment.
A system is not a box of equipment. It is a set of decisions, most of which are invisible once the walls are closed.
What a builder gets out of it
Set against the apparent saving of supply only, the trade is straightforward.
The technology scope has one party accountable for it, which removes it from the builder's coordination load. The fit-off is short, because the system was tested before it arrived. The defects period has a named party who can be called directly. And the handover is done in person, walking the house with the people who live in it, which is the thing the client remembers about the build long after they have forgotten who laid the floor.
None of that shows up as a line in a tender. All of it shows up in the programme.
The honest exception
There are jobs where supply only is the right answer, and they are usually small: a single zone of audio, a camera or two, a retrofit in a house that already has an installer it trusts.
On a whole-home system in a significant house, it is not, and saying so early is better than discovering it at commissioning. Where a budget does not reach a properly delivered system, a smaller system done properly in fewer rooms is a better house than a whole-home system done thinly. That is a conversation worth having at design, when it is still a choice.