National Electrical Code Top Ten Tips: Article 540, Motion Picture Projection Rooms
- While these rooms are becoming increasingly scarce, they still exist. If you want to operate a professional projector, you have to operate it in one of these permanently constructed rooms [540.10].
- A professional projector is one that uses 35 or 70mm film that has 5.4 perforations per inch. Or, it's one that uses carbon arc, xenon, or other light source that develops hazardous gases, dust, or radiation. Thus, the special room [540.2].
- Motor generator sets and transformers for the supply or control of current to the projection equipment must be in another room if nitrate film is used [540.11(A)]. Oddly, 540.11(A) also says, "Where placed in the projection room...." followed by a set of requirements. Since the goal is to keep ignition sources and fuel separate, go the safe route and simply place the two in separate rooms.
- Here are those other requirements just referred to. If in the same room as the projection equipment, motor generator sets and transformers for the supply or control of current to the projection equipment must be of the enclosed, fan-cooled or enclosed peip-ventilated type [540.11(A)(1)] or comply with one of the other five requirements listed in 540.11.
- Overcurrent devices not normally required or used for projectors cannot be installed in projector rooms [540.11(B)]. This means you can't locate a branch circuit panel in that room. Do you see the common theme runnnig through Article 540? Keep ignition sources away from the fuel.
- Any emergency systems associated with these rooms must comply with Article 700.
- You must provide a minimum of 30 inches of working space on each side of each motion picture projector [540.12]. Same for the rear. If you honestly think 30 inches is sufficient, you're ignoring the expansion of waist sizes that has occured over the past few decades. Allow a realistic amount of clearance, if you can get it.
- Supply conductors for outlets for arc and xenon projectors can't be smaller than 8AWG [540.14]. This doesn't mean you can't make them bigger.
- Any cords used on portable equipment must be approved for hard usage [540.15]. Be sure you route them out of harm's way and use cord protectors where applicable. A hard usage cord that gets stepped on a few times or that gets rolled over by on chair wheel of a desk chair occupied by a 220lb man is no longer suitable for hard usage.
- You can also use nonprofessional projectors in these rooms [540.31]. Even if the room is thereafter used exclusively for nonprofessional projectors, that's OK. You don't have to revert anything.