920SIGN LIGHTING

920.1DESCRIPTION —This work is the furnishing and installation of a complete electrical distribution,

control, and lighting system for the illumination of indicated signs.

920.2MATERIAL—Section 1102. Certification and warranties, as specified in Section 910.2(c).

920.3CONSTRUCTION—As shown on the Standard Drawings, as indicated, and as follows:

Do not alter sign structure members to attach electrical items, unless indicated. When necessary, drill during structural fabrication.

as specified in Section 910.3(j). If the luminaire is provided with a remote ballast, mount the remote ballast over the shoulder. Submit mounting method and materials for approval.

Unless another method is specified, attach exposed conduits to sign structures using galvanized or stainless steel supports and U -bolts or two-hole straps with spacers and expansion bolts, and attach the conduit to sign columns and shafts with clamping bands and bolts.

Deviation from the indicated layout may be allowed if it is necessary to overcome obstacles during construction, provided that drawings showing the deviations are submitted for approval. Extend cables from the breakers of each sign structure mounted lighting panel to each ballast and sign lighting fixture. Attach exposed cable runs to the structures using 1/2 -inch stainless steel straps or black plastic tie straps, as directed, at intervals not exceeding 3 feet.

grounding conductors, bonding jumpers, and necessary devices to limit the voltage to earth on the exposed normally non-current carrying metal parts of the entire electrical system and sign structure. At the power supply, connect one end of the No. 4 AWG grounding electrode conductor to the breaker panel ground bus and the other end to the ground rod at the service pole. At each sign structure install a ground rod and install a No. 6 AWG grounding electrode conductor through the sign column shaft and attach to the grounding lug accessible from the handhole. Connect the ground wire to the ground rod with an exothermic weld or a bronze clamp. Do not ground the system neutral conductor. Ground the equipment grounding conductor and enclosure using a connection on the grounding lug in the column shaft. Drive the ground rod vertically into the ground a horizontal distance of 1 foot from the foundation and opposite the roadway side of the shaft.

at the supply side of the highway sign lighting circuit, and make readings at ballasts. Provide a voltage drop not exceeding 5% of the rated voltage at the service point when under full load at the lamp ballast. Take current readings on the load side of each main breaker and neutral circuit. Take current readings at nighttime and at daytime with the lighting systems in normal operation.

920.4MEASUREMENT AND PAYMENT—Lump Sum

The price includes furnishing personnel, equipment, and the costs of electrical energy for the tests.