ARTICLE 650 Pipe Organs.

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.

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

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

650.4 Grounding. The rectifier shall be grounded accord­ing to the provisions in 250.112(B).

650.5 Conductors. Conductors shall comply with (A) through (D).

(A) Size. 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 (ROP 16-19).

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

C) Conductors to Be Cabled. Except for the common-return conductor and conductors inside the organ proper the organ sections and the organ conductors shall be cabled. The common-return conductors shall be permitted under an additional covering enclosing both cable and return conductor, or 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. (ROP 16-20).

     FPN: One method of determining that able is resistant to flame spread is by testing the cable to the VW-1 (vertical wire) flame test in the Reference standard for Electrical Wires, Cables and Flexible cordsANS/UL 1581-1991. (ROP 16-20).

650.6 Installation of conductors. Cables shall be securely fastened in place and shall be permitted to be attached directly to the organ structure without insulating supports. Cables shall not be placed in contact with other conductors.

650.7 Overcurrent Protection. Circuits shall be so arranged that 26 and 28 AWG conductors shall be protected by an overcurrent devise rated at not more than 6 amperes. Other conductor sizes shall be protected in accordance with ampacity. A common return conductor shall not require overcurrent protection. (ROP 16-21).

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