GROUND BONDING STRAP/ROD MISSING/LOOSE

K.  GROUND BONDING STRAP/ROD MISSING/LOOSE:
The grounding wire (should not be spliced) in the main panel connects the neutral bus bar, the panel enclosure, and all other ground wires.

When remote subpanels are utilized, the ground wire must not be connected to the neutral in the sub panel while the ground wires should all be securely mounted on their own bus bar.  The bonding screw on the neutral bus bar of a sub panel should be removed.

The grounding wire that runs from the ground bus within the distribution panel (Fig. K1, Item A) must be connected to a proper ground.  Traditionally, the ground has been the metal plumbing supply pipe feeding the house from the main line in the street.  Plumbers often remove these ground wires from pipes to work on them. Quite often, they forget to replace them when the work is completed (Fig. K1, Item C).  Often too, an effective ground is lost when old street plumbing line is rejuvenated with a new plastic one.  The new electric code also specifies that it must run to a grounding rod driven approximately 8 feet into the earth  (Fig. K1, Item B).

Fig. K1

Sometimes work around the exterior of a house cuts the strap or wire to the grounding rod.  Occasionally the rod is snapped or loosened in the earth.

Bonding of plumbing to bridge some inline plumbing equipment is now required in new construction. Some of these items (not a complete list) are: water heaters, water treatment equipment, water meters, back-flow preventers, pressure reducing/regulating valves, etc. The absence of these bonding wires may create situations wherein the plumbing could become electrified and go unnoticed as a contact hazard.

WHAT TO:   HOW TO:
The grounding of an electrical system must be maintained.  If a wire is found loose or missing, it simply must be replaced.  The same applies for grounding rods on the exterior of houses. Splicing of ground wires is theoretically not permitted but occurs frequently. 

If the ground wires are not bonded to the neutral bus bar at the main panel, the breakers/fuses will not trip/blow when a short circuit occurs.  When the ground and neutrals are not isolated from each other at sub panels, then both wires will carry current back to the main panel.  This can cause possible arcing in concealed spaces and the electrical energizing of pipes and other bonded components.   This could be a severe shock hazard.

Amateurs beware: Repairs and modifications to ground systems should be made only by professional electricians.

REFERENCE: E1, E2, E4, E5, E9, E17