When it comes to electrical safety in the workplace, one of the most important concepts is that of assured grounding. This simply means that there is a path for electricity to follow to the ground in the event of a fault. This is typically accomplished by grounding all of the electrical equipment in the area.
One of the most important aspects of assured grounding is that it provides a path of least resistance for electricity to follow in the event of a fault. This is important because it reduces the risk of electrical shock or fire. Additionally, it can help to prevent damage to electrical equipment.
There are a few different ways to provide assured grounding. The most common method is to ground all of the electrical equipment in the area. This can be done by connecting the equipment to a grounding rod or by using ground wires. Another method is to use grounding transformers. These devices are designed to create a path to ground in the event of a fault.
Assured grounding is an important concept for electrical safety in the workplace. It can help to prevent electrical shock, fire, and damage to equipment. There are a few different methods for providing assured grounding, but the most common is to ground all of the electrical equipment in the area.
Electrical Protection of Employees on Construction Sites
OSHA requires that employers shall use either ground-fault circuit interrupters or an assured equipment grounding conductor program to protect employees on construction sites.
Ground-Fault Circuit Interrupters
All 120-volt, single-phase 15- and 20-ampere receptacle outlets on construction sites, which are not part of the permanent wiring of the building or structure and which are in use by employees, shall have approved ground-fault circuit interrupters for personnel protection.
Receptacles on a two-wire, single-phase portable or vehicle-mounted generator rated not more that 5kV, where the circuit conductors of the generator are insulated from the generator frame and all other grounded surfaces, need not be protected with ground-fault circuit interrupters.
Assured Equipment Grounding Conductor Program
The employer shall establish and implement an assured equipment grounding conductor program on construction sites covering all cord sets, receptacles which are not a part of the building or structure, and equipment connected by cord and plug which are available for use or used by employees. An assured equipment grounding conductor program shall comply with the following minimum requirements:
A written description of the program, including the specific procedures adopted by the employer. The description and procedures shall be available at the jobsite for inspection and copying by OSHA and any affected employee.
The employer shall designate one or more competent persons to implement the program.
Each cord set , attachment cap, plug and receptacle of cord sets, and any equipment connected by cord and plug, except cord sets and receptacles which are fixed and not exposed to damage, shall be visually inspected before each day’s use for external defects, such as deformed or missing pins or insulation damage, and for indications of possible internal damage. Equipment found damaged or defective shall not be used until repaired.
The following tests shall be performed on all cord set, receptacles which are not a part of the permanent wiring of the building or structure, and cord-and plug-connected equipment required to be grounded.
All equipment grounding conductors shall be tested for continuity and shall be electrically continuous.
Each receptacle and attachment cap or plug shall be tested for correct attachment of the equipment grounding conductor. The equipment grounding conductor shall be connected to its proper terminal.
All required tests shall be performed:
- Before first use.
- Before equipment is returned to service following any repairs.
- Before equipment is used after any incident which can be reasonably suspected to have caused damage (for example, when a cord set is run over).
- At intervals not to exceed 3 months, except that cord sets and receptacles which are fixed and not exposed to damage shall be tested at intervals not exceeding 6 months.
The employer shall not make available or permit the use by employees of any equipment which has not met these four requirements.
Tests performed as required in the preceding paragraph shall be recorded. This test record shall identify each receptacle, cord set, and cord- and plug-connected equipment that passed the test and shall indicate the last date it was tested or the interval for which it was tested. This record shall be kept by means of logs, color coding, or other effective means and shall be maintained until replaced by a more current record. The record shall be made available on the jobsite for inspection by OSHA and any affected employee.
One of the methods listed by OSHA as part of acceptable record keeping is to establish a color code for marking cord sets and cord- and plug-connected equipment. The table below lists a color code that is in wide use by electricians and contractors. Colored plastic or vinyl electrical tape is placed on one or both ends of cords and cord- and plug-connected equipment to denote the month that the tests were performed.
|Assured Equipment Grounding ConductorProgram Color Code|
|Month #||Month Tested||Color of tape(s)to apply to cord|