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Significant changes in article 600 - Electric signs and outline lighting

1999 National Electrical Code

Section 600-6 Disconnects

Revised ROP 18-98, 101 ROC 18-82a

This section has been revised by clarifying that each sign and outline lighting system, "or feeder circuit or branch circuit supplying a sign or outline lighting system," shall be controlled by a disconnecting means. New wording has also been added to require signs and outline lighting systems located within fountains to have a disconnect located in accordance with Section 680-12. The required disconnects shall be within sight of the sign or outline lighting, or where not located within sight shall be capable of being locked in the open position. The revision clarifies that for multiple section signs a disconnect is permitted but not required for each section. A single disconnect in each feeder or branch circuit would be permitted if it met all conditions. This section previously was misinterpreted to require a single disconnect regardless of how many circuits fed a multiple section sign.

Section 600-7 Grounding

Revised ROP 18-103 ROC 18-89

(Note - As used in this article, the use of the words "grounding" and "bonding" are intended to have different meanings. Bonding is a more accurate term with regards to conductivity of metal parts in secondary sign circuits). This section has been revised to permit listed flexible metal conduit or listed liquidtight flexible metal conduit that encloses secondary circuits as a bonding means in lengths not exceeding 100 feet. Small parts not exceeding 2 inches in any dimension, not likely to become energized, and spaced at least 3/4 inch from neon tubing are not required to be bonded. Flexible nonmetallic tubing has been deleted as an acceptable wiring method. However, listed nonmetallic conduit is permitted (rigid or flexible). If nonmetallic conduit is used, a bonding conductor not smaller than No. 14 copper shall be installed separate and remote and be spaced at least 1-1/2 inches from the conduit when the circuit is operated at not over 100 Hz, or 1-3/4 inches at over 100 Hz. Spacing of bonding conductors is necessary to reduce the deteriorating effects of corona and ozone on the nonmetallic conduit. Metal parts of buildings shall not be used for grounding purposes. A new Fine Print Note refers to Section 600-32(j) for restrictions on lengths of secondary conductors in metal raceways (20' maximum).

Section 600-23(f) Marking

New ROP 18-118

This new section has been added to require that transformers and power supplies shall be marked to indicate they have secondary fault protection. To reduce the risk of fire, the 1996 NEC was revised to require listed transformers and electronic power supplies to have secondary ground-fault protection. The two previous exceptions were converted into positive code language. (Note - The availability of such equipment with secondary protection has significantly improved. Unless otherwise exempt by the NEC, the Board of Electricity will be enforcing the requirement for secondary ground -fault protection commensurate with the adoption of the 1999 NEC in Minnesota on July 1, 1999). The ground-fault protection required by this section should not be confused with GFCI protection for personnel.

Section 600-32(a) Secondary Wiring Method

Revised ROP 18-122, 124 ROC 18-111

This section has been revised by deleting electrical nonmetallic tubing as a permitted wiring method for neon secondary conductors over 1000 volts. However, listed nonmetallic conduit is permitted (rigid or flexible). Nonmetallic conduit that encloses a conductor that is operated at 100 Hz or less shall be spaced 1-1/2 inches from grounded or bonded parts (1-3/4 inches when operated over 100 Hz). Spacing is necessary to reduce the deteriorating effects of corona and ozone on the nonmetallic conduit. ENT was deleted as an acceptable wiring method because it is too flexible and maintaining the required spacing is very difficult.

Section 600-42(f) Wet Locations

Revised ROP 18-131 ROC 18-133

This section has been revised and the rules for "electrode receptacles" are separate from "bushings". Where electrode receptacles penetrate a building, a listed cap shall be used to seal the opening between the neon tubing and the receptacle. Where a bushing or neon tubing penetrates a building, the opening between the tubing and the bushing shall be sealed. The previous wording requiring "silicon sealant" has been deleted so as not to limit the methods of complying with the code.

Section 600-42(g) Electrode Enclosures

New ROP 18-132

This new section requires electrode enclosures to be listed for the purpose. The substantiation for this new section was to reinforce the rules in Section 600-42(b) that already require connections to be electrically and mechanically secure and be in an enclosure listed for the purpose. (Note - Electrode receptacles and electrode enclosures perform a similar function except in the way the connection is made between the neon tubing and the GTO cable).

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