Manhole
From Wikipedia, the free encyclopedia
A manhole (alternatively utility hole, maintenance hole or access chamber) is the top opening to an underground utility vault used to house an access point for making connections or performing maintenance on underground and buried public utility and other services including sewers, telephone, electricity, storm drains and gas. It is protected by a manhole cover, a (usually metal) plug designed to prevent accidental or unauthorized access to the manhole. Manholes are usually outfitted with metal or polypropylene steps installed in the inner side of the wall to allow easy descent into the manhole.
Manholes are generally found in urban areas, in streets and occasionally under sidewalks. They are usually in circular shape to prevent accidental fall of the cover in the hole.
In rural and undeveloped areas, services such as telephone and electricity may be carried on pylons rather than underground.
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[edit] Hazards caused by stray voltage in manholes
In urban areas, stray voltage issues have become a significant concern for utilities. In 2005, Jody Lane was electrocuted after stepping on a manhole cover, while walking her dog in New York City. One solution is the Electrified Cover Safeguard invention, which is an on site, real time stray voltage warning system which is being used in the street lights in New York City and is also being tested by Con Edison and other utilities and municipalities in England, Europe, and Japan.
[edit] Feminist issue with manhole name
In 1990, the city of Sacramento, California officially renamed all their manholes to "maintenance holes" out of concern for the equality of both genders [1]. The name "maintenance hole" was selected because the term shares the same initials as the word "manhole," thereby eliminating the need to change the MH labels on the city's utility maps.
