National Electrical Code Top Ten Tips:
Article 522 -- Control Systems for Permanent Amusement Attractions
- Article 522 applies to control circuit power sources and conductors for permanent amusement attractions.
- A control circuit carries the electrical signals for controlling the equipment, but does not carry the power. Example: The 120V motor speed control and start/stop circuits belong to the controls, the 480V power to the motor itself does not.
- What does the NEC mean by "permanent?" For Article 522, it means that transporting or relocating the equipment is impractical [522.2]. That does not mean it's impossible. Basically, if you don't typically remove the equipment at the end of the season (or during), it's permanently installed.
- Only "qualified personnel" can service this equipment [522.7]. An untrained operator with a pair of pliers isn't a qualified person. A factory-trained technician with specific training on this specific equipment is.
- The two types of control circuits are power-limited (under 30V and under 1,000A) and non power-limited. The latter cannot exceed 300V [522.10].
- The overcurrent protection devices for power-limited control circuits can't be rated for more than 167% of the following: VA rating divided by the rated voltage [522.10].
- You can't use aluminum conductors in the control circuits [522.20].
- If using conductors 16AWG or smaller, ensure they comply with Table 522.22.
- Though it's a poor engineering decision, you can run control and power wiring in the same raceway. But to do so you must meet the criteria of 522.24(B).
- Where wet contact is likely to occur, ungrounded 2-wire control circuits are limited to 30VDC (or 12.4VDC peak for DC that's continually interrupted at a rate of 10 to 200 Hz) [522.28].