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For other uses, see Manhole (disambiguation).
PMG manholes in a city street, Perth, Western Australia.
Manhole in Belo Horizonte, Brazil.
This is a sewer manhole, exposed during construction. Typically, only the top ring and manhole cover (not pictured) would be visible.
Manhole cover of precast concrete in Germany

A manhole (alternatively utility hole, cable chamber, maintenance hole, inspection chamber, access chamber or confined space) 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.


Manhole closings are protected by a manhole cover (also known as a "biscuit"[citation needed]), a flat plug designed to prevent accidental or unauthorized access to the manhole. Those plugs are traditionally made of metal, but may be constructed from precast concrete, glass reinforced plastic or other composite material (especially in Europe, or where cover theft is of concern).

Manholes are usually outfitted with metal, polypropylene, or fiberglass steps installed in the inner side of the wall to allow easy descent into the utility space. Because of legislation restricting acceptable manual handling weights, Europe has seen a move toward lighter weight composite manhole cover materials, which also have the benefits of greater slip resistance and electrical insulating properties.

The access openings are usually circular in shape to prevent accidental fall of the cover into the hole.

Manholes are generally found in urban areas, in streets and occasionally under sidewalks. In rural and undeveloped areas, services such as telephone and electricity are usually carried on utility poles or even pylons rather than underground.

Composite manholes[edit]

Composite (fiberglass) manholes are commonly used in applications where infiltration, exfiltration, or corrosion by hydrogen sulfide (from sewer gas) are a concern, or where structures need to be factory integrated into a manhole before placement.

Structures commonly integrated into composite manholes include:

  • Flow inverts[1]
  • Flumes[2]
  • Drop structures from higher elevation flows to lower elevation discharge pipes

Occasionally, composite manholes will integrate:

  • Weirs[3]
  • Storm water screening structures[4]
  • Sewage grinders[5]
  • Energy absorbing structures to dissipate undesirable flow stream turbulence or velocity[6]

Hazards caused by stray voltage in manholes[edit]

In urban areas, stray voltage issues have become a significant concern for utilities. In 2004, Jodie S. Lane was electrocuted after stepping on a metal manhole cover, while walking her dog in New York City.[7] 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 ConEd and other utilities and municipalities in England, Europe, and Japan.[citation needed]

See also[edit]



  • Isles, Paul (2010). "Dover Engineering Works". Dover Life Magazine

Further reading[edit]

  • Ascher, Kate ; researched by Wendy Marech (2007). The works : anatomy of a city (Reprint. ed.). New York: Penguin Press. ISBN 978-0143112709. 

Original courtesy of Wikipedia: http://en.wikipedia.org/wiki/Manhole — Please support Wikipedia.
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4554 news items


Fri, 17 Oct 2014 07:39:32 -0700

Watch Manager Jim Farrell who was at the scene said: “There was lots of very thick, black smoke pulsing from the manhole and crews worked quickly to contain the fire. The Brigade goes to around 50 incidents involving electrical manhole covers every ...

Calgary Herald

Calgary Herald
Sun, 19 Oct 2014 19:44:56 -0700

There are three of them around the core: one just across the CP train tracks from City Hall, one in the shadow of the Husky towers on 9th Avenue S.W., and one near the Louise Bridge — about a block from the manhole the blue smoke of burning plastic ...

Arab News

Arab News
Thu, 16 Oct 2014 13:37:30 -0700

The Civil Defense officer, who rushed to save a father and son after they fell into a manhole in front of a mall in Jeddah on Tahlia Street, has cited new details of the incident that resulted in the death of Ali Mohammad Mansho and his five-year-old son.

Times of India

Times of India
Sun, 05 Oct 2014 16:48:36 -0700

A 66-year-old man, who was returning home after celebrating Dasara at a relative's house, died after he fell into an open manhole at Himayatnagar. Though he fell on Saturday night, the incident came to light on Sunday when locals and sanitation workers ...

Cibola County Beacon

Cibola County Beacon
Fri, 17 Oct 2014 07:35:01 -0700

Apparently, two service men from Gallup entered a manhole on the parking lot of Denny's on Grants' west end to work on the restaurant's waste system. Apparently, the service men were met with a toxic fume in the hole that caused them to lose ...
MSN Canada
Wed, 15 Oct 2014 05:05:03 -0700

In the blackout's fourth day, Enmax and Calgary Fire officials continued to avoid giving any indications about what they suspect caused the weekend's manhole blaze, though Mayor Naheed Nenshi clarified there's no evidence the small but vital concrete ...
Curbed National
Mon, 13 Oct 2014 08:04:32 -0700

Scrappers have taken to stealing Detroit's manhole covers, putting pedestrians at risk for an unexpected (and often deadly) trip to the city's sewers. This nightmarish problem is finally getting the attention it deserves, with the Detroit Water and ...

The Hindu

The Hindu
Fri, 17 Oct 2014 07:37:30 -0700

Due to huge water-logging in Whites Road where many government, private undertakings and banks are located, pedestrians struggled in between Patullos Road and Satyam Theatre junctions. A student fell into a manhole and was rescued by a passerby (in ...

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