SECTION 920 — SIGN LIGHTING

920.1 DESCRIPTION — This work is the furnishing and installation of a complete electrical distribution, control, and lighting system for the illumination of indicated signs.


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


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

(a) General. Section 910.3(a) and as follows:
Do not drill sign structure members to attach electrical items, unless indicated. When required, drill during structural fabrication.

(b) Trench Excavation and Backfill. Section 910.3(c)

(c) Service Pole Installation. Section 910.3(k)

(d) Photoelectric Control Device. Section 910.3(m)

(e) Enclosure Installation. Section 910.3(n)

(f) Luminaires. Attach luminaires to the supports. Install the indicated lamp in each lighting fixture. Clean luminaires as specified in Section 910.3(j).

(g) Junction Boxes. Section 910.3(p)

(h) Conduit Installation. Section 910.3(g) and as follows:
Unless another method is indicated, attach exposed conduits to sign structures, using galvanized steel supports and U-bolts or two-hole straps with spacers and expansion bolts, and attach to sign columns and shafts, with special clamping bands and bolts.

(i) Cable Installation. Section 910.3(h)
The layout of cable or conduit indicated is subject to changes required to facilitate the work. Where necessary to overcome obstacles during construction, deviation from the indicated layout may be permitted, provided drawings showing such deviations are submitted for acceptance.
Extend cables, from the breakers of each lighting panel mounted on the sign structure 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 by the Engineer, at intervals not exceeding 3 feet.

(j) Cable and Conduit Markers. Section 910.3(t)

(k) Grounding. Install grounding wire, ground rods, connectors, and necessary devices to satisfactorily ground the entire electrical system and sign structure.
At the service pole, connect the No. 6 AWG ground wire to the breaker panel ground bus and to the ground rod.
At sign structures, install a No. 6 AWG ground wire entering the sign column shaft and attach to the grounding lug opposite the handhole. Connect the ground wire to the ground rod with an acceptable bronze clamp. Ground the system neutral conductor and enclosure, using an adequate 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, opposite the roadway side of the shaft.

(m) Tests. Section 910.3(u), except as follows:

2. Circuit Tests. Make voltage readings at the power supply side of the service pole equipment or 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 circuits. Take current readings at nighttime and daytime with lighting systems in normal operation.

3. Performance Test. As directed, take footcandle readings at several points on each sign face. Adjust the angle of the luminaire for the best light uniformity over the entire sign surface.

(n) Guarantee. Section 910.3(v)


920.4 MEASUREMENT AND PAYMENT — Lump Sum
Includes furnishing personnel, equipment, and the costs of electrical energy required for the tests.

No Supplement

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