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The practical half · printed pages 13 to 14

Direct Connection, and Street Lighting

The first choice whenever there is something safe to clip onto, worked through on a lighting column.

Direct Connection Using the Genny

Printed page 13

Ensure there is a noticeable drop in Genny tone when a direct connection is made to a metallic structure (except when the capacitance method is used). If no drop in tone is heard, ensure the connection or earth is good.

A suitable earth is: the supplied Genny earth pin in the ground, a buried metal structure (i.e. a manhole lid), or use of water on the earth pin or placing it in a puddle.

Earth pin in grass at a shallow angle with the Genny's earth lead clipped on.
Fig 01Earth pin in grass at a shallow angle with the Genny's earth lead clipped on.
Genny set up on paving with leads run out to the connection, and a water bottle beside: water used to improve the earth.
Fig 02Genny set up on paving with leads run out to the connection, and a water bottle beside: water used to improve the earth.

Locating Street Lighting Cables

Printed page 14

To locate street light cables, the Genny should be connected as follows:

  • 01Switch the Genny on and insert the connection leads.
  • 02Connect the black lead to a suitable earth as close to the column as possible.
  • 03Connect the red lead to the metalwork of the column.
  • 04Adjust the signal level control so that the CAT display is set to half scale.
  • 05Where possible, walk around the column making a note of any signal(s) detected.

Once a signal has been detected and the direction has been established, the route can be followed.

Cables to and from other street furniture may also be detected by making a direct connection to the metal structure.

Genny at the base of a galvanised lighting column: connection lead to the column, earth pin alongside.
Fig 01Genny at the base of a galvanised lighting column: connection lead to the column, earth pin alongside.
Operative circling a lighting column with the CAT while the Genny sits at its base: the search worked around the column, arrow overlay showing the path.
Fig 02Operative circling a lighting column with the CAT while the Genny sits at its base: the search worked around the column, arrow overlay showing the path.
Training group watching a locate at a lighting column on open grass.
Fig 03Training group watching a locate at a lighting column on open grass.
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Direct connectionEarthingCapacitance