Shop clip for magnesium galvanic anodes, sold in standard weights such as 9, 17, 32 and 48 lb and prepackaged in backfill. High-potential magnesium alloy develops roughly -1.75 V CSE and standard alloy about -1.55 V, far more driving voltage than zinc, which makes mags the go-to for coated steel in dry or high-resistivity soil, tanks and service lines. In low-resistivity soil they burn out quickly and can overprotect.
Drop two 32 pound mag anodes at the low spot and tie them into the test station.
Also heard as
- mags
- magnesium anode
- high potential mag
Related terms
Sacrificial anode
Block of a more active metal such as magnesium, zinc or aluminum that corrodes to protect connected steel.
Zincs
Boat and marine slang for the sacrificial anodes bolted to hulls, shafts, outdrives and heat exchangers.
Soil resistivity
How strongly soil resists electric current, in ohm-cm, the main guide to soil corrosivity and anode design.
Test station
Above-ground post or box with wires bonded to a buried structure, used to take CP readings.