DOT•PLUG Breakaway Wiring System for Roadway Lighting Systems
AASHTO Breakaway Wiring Requirements
In 1996 McGraw/Hill published the first edition of the "Highway Engineering Handbook" introduced a new breakaway wiring methods/products that were being pioneered by MG Squared for the Alabama DOT at the time. Following this publication, the Federal Highway Administration (aka FHWA, US DOT) issued their own publication and guidelines - No. FHWA-HI-97-026: which duplicated the standards and designs based upon the MG Squared breakaway system set in the Highway Engineer Handbook.
In 1998 AASHTO addressed their concerns in regards to the electrical wiring inside breakaway (frangible) roadway lighting poles and issued an Interim to the Standard Specifications for Structural Supports for Highway Signs, Luminaires and Traffic Signals stating:
MG Squared's pioneering breakaway cable system had become the sole standard for a true AASHTO compliant system. Referred to in these early publications as a "Modular Cable System", "Modular Pole Cable Distribution System" (MCDS), "Pole Cable Distribution System" (PCDS, MG Squared decided to name their breakaway cable system the DOTPLUG breakaway cable system and is marketed under this name today.
Soon after 1998 AASHTO interim, some state DOT engineers were aggressive to meet these new safety standards while many have ignored and not enforced the breakaway wiring requirements. By the new millennium, research and studies revealed more and more documented cases of motorists who survived the impact with a luminaire pole, only to be subsequently killed from the resulting explosion, fire, or electrocuted from exposed conductors on, near or under a vehicle. The explosion and fire are usually caused when the fuel tank ruptures, the vehicle having been caught on an improperly constructed foundation, and the electrical system sparks repeatedly until the fuel explodes. In other incidences, medical personnel have been delayed from attending to victims because of the risk of electrical shock from exposed conductors near or under a vehicle (McGraw/Hills "Highway Engineering Handbook, 2 ed.").
In 2001 AASHTO updated their standard specifications once again for structural supports to read as:
The MG Squared DOTPLUG breakaway cable system is still today the leading system that meets current AASHTO
standards and avoids the electrical and fire hazards of the conventional
wiring method. Avoiding these hazards also greatly reduces the
liability of the DOT, Utility Companies, design engineers, and others in
relation to the electrical wiring system. Another benefit from the use of
this type system is the reduction of maintenance/repair cost and time.
Further advances like the incorporation of a "ground fault circuit
interrupter" (GFCI/ELCI) into the wiring systems is helping avoid fatal
and costly accidents resulting from worn or poorly maintained Municipal
lighting systems. It is essential that as a DOT, Municipality, Utility
Company or as a electrical engineer; that they be educated to avoid these
hazards and to abide by all current AASHTO and/or Electrical Standards.
Copyright MG Squared 2012