Hydro Excavation

Hydro Excavation Safety

The risk to Hydro excavation operators and directional boring equipment operators, when daylighting is higher than many would expect. Even when not purposefully excavating Under Ground Power Cables the risk for electrocution is very real.  

Hydro Excavation Operators when excavating are exposed to the risk of electrocution from several different ways:

 

 When excavating Under Ground Power Cables – On purpose or accidentally

 When Excavating Water Lines – Metallic water lines can and have carried electrical current.  

When Excavating Under Overhead Power Lines – Hydro Excavating under overhead power lines can and have resulted in fatalities.

 When Excavating Around or Near Under Ground Power Cables – even with properly marked cable locations.  As an example an incident occurred where a Hydro excavation operator was daylighting a waterline and seepage of water from the excavation “flowed” over to a poor electrical under ground splice and knocked the operator off of his feet from the electrical shock.

With the proper training and equipment risk of electrocution can be significantly reduced.  The way that operators are protected is by making them like a bird on an energized wire, where the entire system can be energized but the operators hands and feet are all at the same potential, thus there will be limited current flow through the operator.  This is called an Equipotential Zone.

Better Understanding an Equipotential Zone – Voltage is the pressure that will push the current or amps through the electrical system.  The amps or current is the part of the electricity that will hurt or kill you, so the objective is to reduce the amount of current or amps that can flow through the operators body.

Step Potential The Hidden Risk – One of the other things about electricity that must also be explained, is what happens when electricity enters the earth and what happens when there is a line strike.  Any time electricity enters the ground or earth there will be “rings” of different voltage levels around the equipment involved in allowing the electricity to enter the earth.  These rings in the ground are called Step Potential.  In other words, a person can be standing on the ground not touching anything and get electrocuted by step potential in the ground.

 

Due to the inherent risk many utility companies are requiring Hydro Excavation Operators to become qualified for exposing high voltage cable and develop safe work practices such as the utilization of the Kri-Tech Bond Mat.

Properly applied the bond mat accomplishes compliance with the OSHA 1910.269 requirement which states

“Equi-Potential Zone: temporary protective grounds shall be placed at such locations and arranged in such a manner as to prevent each employee from being exposed to hazardous differences in electrical potential”

You can request a copy of the recommended safe work practice guidance document and vehicle set up document (request information here) to review how the bond mat can be implemented into your safe work plan.  Please note local laws / regulations take precedents over the described methods.

The portable mat consists of a high-ampacity tinned copper braid cable sewn in a grid pattern on to a high strength flexible membrane.  The braid has an inner conductor and a separate outer perimeter conductor for superior protection.