Manholes are placed at intervals in the line of ducts to facilitate the drawing in and jointing of the cables, and surface boxes are placed in the footways for distributing purposes.
In one system the main cables terminate in large airtight iron boxes placed in the manholes.
In its more complete form a still has in addition the following fittings: - The dome is provided with openings to admit (I) the axis of the stirring gear (in some stills the stirring gear rotates on a horizontal axis which traverses the side and not the head of the still), (2) the inlet and outlet tubes of a closed steam coil, (3) a tube reaching to nearly the bottom of the still to carry live steam, (4) a tube to carry a thermometer, (5) one or more manholes for charging purposes, (6) sight-holes through which the operation can be watched, and (7) a safety valve.
In November they installed three manholes and the interconnecting pipes for the sewer diversion to be completed after the pound is lowered.
Other road defects that can cause damage to cars include sunken manholes and metal edges.