Article 645

Pipe Organs

1. Scope. This article covers those electrical circuits and parts of electrically operated pipe organs that are employed for the control of the keyboards and of the sounding apparatus, typically organ pipes.
   Informational Note: The typical pipe organ is a very large musi‐cal instrument that is built as part of a building or structure.N
2. Definitions.Electronic Organ. A musical instrument that imitates the sound of a pipe organ by producing sound electronically.Informational Note: Most new electronic organs produce sound digitally and are called digital organs.Pipe Organ. A musical instrument that produces sound by driving pressurized air (called wind) through pipes selected via a keyboard.Sounding Apparatus. The sound-producing part of a pipe organ, including, but not limited to, pipes, chimes, bells, the pressurized air (wind)-producing equipment (blower), associ‐ ated controls, and power equipment.Informational Note: The sounding apparatus is also referred to as the “pipe organ chamber.”
3. Other Articles. Installations of circuits and equipment shall comply with 650.3(A) and (B) as applicable. Wherever the requirements of other articles in Chapters 1 through 7 of this Code and Article 650 differ, the requirements of Article 650 shall apply.

1. ARTICLE 660 — X-RAY EQUIPMENT
   1. Electronic Organ Equipment. Installations of digital/ analog–sampled sound production technology and associated audio signal processing, amplification, reproduction equip‐ ment, and wiring installed as part of a pipe organ shall be in accordance with Article 640.
   2. Optical Fiber Cable. Installations of optical fiber cables shall be in accordance with Parts I and V of Article 770.
   Informational Note: Class 1 power-limited power supplies areoften utilized in pipe organ applications.
2. Source of Energy. DC power shall be supplied by a listed dc power supply with a maximum output of 30 volts.

ampacity. A common return conductor shall not require over‐ current protection.

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650.9 Protection from Accidental Contact. The wiring of the sounding apparatus shall be within the lockable enclosure (organ chamber) where the exterior pipes shall be permitted to form part of the enclosure.

Informational Note: Access to the sounding apparatus and the associated circuitry is restricted by an enclosure. In most pipe organ installations, exterior pipes form part of the enclosure. In other installations, the pipes are covered by millwork that permits the passage of sound.

or Double Insulation of the DC Power

1. Grounding
   1. The dc power supply shall be double insulated.
   2. The metallic case of the dc power supply shall be bonded to the input equipment grounding conductor.