Section 27-505. Illuminated signs

General. All ground signs, wall signs,
  roof signs, projecting signs,  and  marquee  signs  may  be  lighted  by
  internal   or   external  sources  when  complying  with  the  following
  requirements:
    (1)  ILLUMINATION.  No  sign  shall  be  illuminated  by  other   than
  electrical  means.  All  wiring and accessory electrical equipment shall
  conform to the provisions of the electrical code  of  the  city  of  New
  York.
    (2)   MATERIALS.  Every  illuminated  sign  shall  be  constructed  of
  noncombustible materials except as permitted in section 27-507  of  this
  article.
    (3)  PERMISSIBLE  PROJECTIONS.  Lighting reflectors may project beyond
  the top or face of all signs, provided that every part of such reflector
  is at least ten feet above the ground or  sidewalk  level.  In  no  case
  shall  such  reflectors  project beyond a vertical plane two feet inside
  the curb line. Reflectors shall be constructed, attached, and maintained
  so that they shall not be, or become, a hazard to the public.