Temporary Protective Grounding

Temporary protective grounds are recommended to be serviced annually or if damage is suspected. 

Temporary Protective Grounds (TPG's), Personal Protective Grounds (PPG's), Cluster Sets, Three-ways. Conductor size can range is size from #2, 1/0, 2/0, 4/0 as well as clamp and ferrule style.

The process for cleaning the TPG starts with the cable, soap, water and ISO-propylene if required. At the same time the cable is inspected for cuts (more then 50% of the jacket) kinks, bulges, flattened cable and exposed strands. If they do not pass the visual inspection the TPG is marked as failed until a repair is completed. 

If the cable passes the visual inspection, the next part of cleaning is servicing the clamps and ferrules. Both clamps are removed and serviced by cleaning the hardened debris and most importantly the contact points where corrosion and oxidization build up. A mechanical inspection is completed to make sure the jaw opens and closes correctly on all styles of clamps. The clamps are inspected for any cracking or looseness when tightened and if they are found non-compliant, they are visually failed until a repair is completed.

With the clamps still off the TPG, the ferrules are wire brushed removing any corrosion and oxidization. If the ferrule threads need to be rethreaded this is completed at this point. Strain relief is also assessed at this stage of inspection. If the strain relief is in good working order, it remains intact; however, if the ferrule or strain relief are damaged, they will be repaired.

Over time it is expected there will be an increase in impedance from normal deterioration of the assembly due to aging, contamination and corrosion, particularly in the contact areas of the cable ferrules and clamps. Therefore, the acceptable impedance should not be less then 95% of expected impedance value of the assembly.

Visual inspection criteria not being met and electrical failure.

 Proper storage of TPG’s can prevent mechanical, cable and moisture damage. Avoiding these specific types of damage will not only ensure the equipment works when required, it will also extend the life of the equipment. The following are recommendations on how to properly store TPG’s when they are not is service.

TPG’s when stored in the shop or in a truck should always be secured to a wall either by a hook or cable rack. If a hook is used it should have enough surface area as though it does not kink the cable. Storage off the ground will also ensure no moisture on the ground can contact the TPG and cause corrosion inside the cable or on the ferrules or clamps. Proper securement of the TPG’s will also ensure clamps are not being broken and cables are not being punctured by clamps.

Another option for the storage of TPG’s is bags for each individual TPG, however you want to ensure the TPG in the bag is stored off the ground away from moisture. 

Adhesive tape used to bundle TPG’s together is not recommended because the tape when removed leaves behind the adhesive that collects debris making it difficult to inspect for nicks or punctures on the cable in the field and may hide damaged cable. In addition when the tape is removed a sharp object is typically used to remove the tape and can lead to unnecessary cuts in the cable jacket.