650.1 Scope. This article covers those electrical circuits and parts of electrically operated pipe organs that are employed for the control of the sounding apparatus and keyboards.

650.3 Other Articles. Electronic organs shall comply with the appropriate provisions of Article 640.

650.4 Source of Energy. The source of power shall be a transformer-type rectifier, the dc potential of which shall not exceed 30 volts dc.

650.5 Grounding. The rectifier shall be bonded to the equipment grounding conductor according to the provisions in Article 250, Parts V, VI, VII, and VIII.

650.6 Conductors. Conductors shall comply with

650.6(A) through (D).

(A) Size. Conductors shall be not less than 28 AWG for electronic signal circuits and not less than 26 AWG for electromagnetic valve supply and the like. A main common-return conductor in the electromagnetic supply shall not be less than 14 AWG.

(B) Insulation. Conductors shall have thermoplastic or thermosetting insulation.

Conductors to Be Cabled. Except for the common- return conductor and conductors inside the organ proper, the organ sections and the organ console conductors shall be cabled. The common-return conductors shall be permitted under an additional covering enclosing both cable and return conductor, or they shall be permitted as a separate conductor and shall be permitted to be in contact with the cable.

(D) Cable Covering. Each cable shall be provided with an outer covering, either overall or on each of any subassemblies of grouped conductors. Tape shall be permitted in place of a covering. Where not installed in metal raceway, the covering shall be resistant to flame spread, or the cable or each cable subassembly shall be covered with a closely wound listed fireproof tape.

FPN: One method of determining that cable is resistant to flame spread is by testing the cable to the VW-1 (vertical-wire) flame test in the ANSI/UL 1581-2001, Reference Standard for Electrical Wires, Cables and Flexible Cords.

650.7 Installation of Conductors. Cables shall be se- curely fastened in place and shall be permitted to be at-

tached directly to the organ structure without insulating supports. Cables shall not be placed in contact with other conductors.

650.8 Overcurrent Protection. Circuits shall be so ar- ranged that 26 AWG and 28 AWG conductors shall be protected by an overcurrent device rated at not more than 6 amperes. Other conductor sizes shall be protected in accordance with their ampacity. A common return conductor shall not require overcurrent protection.