A groundbed in which a string of anodes is suspended in a cased or open hole, typically 30 to 150 m deep, packed with conductive coke backfill and fitted with a vent pipe to release the gases formed at the anodes. Deep anodes reach low-resistivity layers below dry surface soil, use very little right-of-way and spread current widely with less interference. Gas blocking and cable failure are the common problems.
No room for a surface bed in town, drill a deep anode at the station and vent it properly.
Keep the vent pipe open. Gas from the anodes needs a way out, or gas blocking slowly chokes the bed's output.
Also heard as
- deep well groundbed
- deep anode bed
- deep well
Related terms
Groundbed
Group of impressed-current anodes buried in backfill that discharges rectifier current into the earth.
Coke breeze
Crushed carbon backfill packed around impressed-current anodes to lower resistance and extend anode life.
MMO
Mixed metal oxide anode: titanium coated with precious-metal oxides, the standard long-life ICCP anode.
ICCP
Impressed current cathodic protection: CP powered by a rectifier pushing current through long-life anodes.