Basics 11. Planning the light in a room: layout, channels, power, rigging

Theory is over — we are going to the venue. This lesson is about what happens before the first cable comes out of the case: how many fixtures you need, where to rig them, whether you have enough channels and, above all, whether the electrics will take it.

Light starts with roles, not with fixtures

A common mistake is buying «nice effects». Light in a venue solves several different jobs, and spectacular beams are not the first of them.

Three typical layouts

Which fixtures exist and what each can do we covered in lesson five.

DJ booth (a small party). Two wash fixtures at the edges of the booth aimed at the dance floor, plus two effect fixtures behind or above. A hazer to the side. Four or five fixtures in total — the minimum kit that already looks like a show.

Small venue (banquet, wedding, 80–120 people). Six to eight wash fixtures around the perimeter (colouring the walls and setting the mood), two to four heads over the dance floor, a strobe or blinder for accents, a hazer. An important detail: washing the walls creates the feeling of a «dressed room» far more than any beams do.

Stage (concert, showcase, conference). Four to six front fixtures on the front truss, the same number of backlights behind, side light at the edges, a wash on the backdrop. Effects come on top of that, if budget and truss allow.

Practical guidelines on geometry:

• front light at roughly 45° from above: higher gives shadows under the eyes, lower shines into them;
• backlight goes higher and behind the performer, so the beam does not hit the camera lens;
• fixtures over the dance floor are rigged so that beams do not hit seated guests in the eyes;
• beam heads and lasers must never be aimed at face level.

Count the channels in advance

This is the simple arithmetic from lesson three, but it has to be done before you buy, not at the venue.

An example for a small venue:

128 out of 512 is a comfortable margin: you can add fixtures without rebuilding the line. If the total is creeping towards 450–500, plan a second universe straight away.

While you are at it, draw up an address map: fixture — address — mode. A sheet of paper or a note on your phone will do. On site that map saves tens of minutes.

Electricity

Light runs off ordinary mains, and the main risk is overloading a circuit.

What you need to know about load. A normal domestic socket on a 16 A breaker takes roughly 3.5 kW, and loading it to the brim is unwise — a sensible limit is around 2.5–3 kW per circuit. LED fixtures are frugal: a wash light draws 50–150 W, an LED head 100–300 W. A fog machine with a heater, however, draws 900–1500 W, and it is the greediest device in the rig.

Let’s estimate that same venue:

That is already close to the limit of one socket circuit — and the same circuit usually carries the sound system, chargers and everything else.

Practical rules:

1. Spread the load across different socket circuits — lighting on one, sound on another.
2. Put fog machines and hazers on their own circuit. Their heaters cycle on and off, creating surges.
3. Use extension leads with adequate conductor size, and unwind cable drums completely: coiled cable overheats under load.
4. Check that the venue’s main breaker will take your lighting alongside the sound and the kitchen. In an unfamiliar venue, ask the management what power is allocated.
5. When in doubt, call an electrician. Connecting to a distribution board, three-phase supply and changing breakers are not a lighting operator’s job.

Rigging: rules that are not up for discussion

A lighting fixture is a lump of metal weighing anywhere from one to thirty kilograms, hanging over people’s heads.

• Clamp — the standard fixing to truss or a bar. Tighten it fully and check it by hand.
• Safety cable — mandatory for every rigged fixture. The steel cable goes around the truss and hooks into the dedicated eye on the housing. It holds the fixture if the clamp fails.
• Load ratings of truss and ceiling. Every structure has a limit; rigging «by eye» is not acceptable. Attaching to building structures must be agreed with the venue.
• Do not rig fixtures directly above people where it can be avoided: over walkways, the bar, the guest area.
• T-bar stands — use counterweights and do not exceed the stated height and load. A stand is easily knocked in a crowd, so keep it out of walkways and barrier it off if you can.
• Check after rigging: give it a tug, look at the tightening, make sure cables are not taut and not pulling on the fixture.

A plan on paper is the best investment

Before the get-in, draw a plan view of the room: where the stage is, where the fixtures go, where each one points, what address it has. Half an hour at a desk replaces two hours of running around on site.

A minimum packing list: fixtures, power and DMX cables with spares, XLR 3↔5 adapters, terminators (two), a spare interface, extension leads, cable ties, tape, tools, the address map, safety cables.

Key points

• Light is planned by roles: front, backlight, side, background wash, effects, atmosphere.
• Front light is mandatory if there is video; beams must not hit guests in the eyes.
• Count channels in advance: the rig total with a margin, otherwise you will need a second universe.
• An ordinary socket circuit is about 2.5–3 kW; put fog machines on their own, unwind cable drums.
• A safety cable on every rigged fixture; clamps tightened and checked.
• Fixtures get hot: air around them, distance to surfaces, and only protected models outdoors.
• A room plan and an address map save more time on site than any skill.

Coming next: the final lesson — troubleshooting. We will gather everything we have learned into one «symptom → cause → what to do» routine, and leave you a cheat sheet with every term from the course.