High Voltage Gloves
Electricity can be deadly – anything above 32 volts is considered dangerous, but the real danger is not the voltage but the current. When you touch a doorknob in the winter and get sparked, you are feeling about 50,000 volts! Why doesn’t this kill you? The current is minimal and for a very short time. Typically, a current flow below about 1 milliamp is too low to feel, and anything above about 15 milliamps will kill you. With that being said, if you work on power lines you know it is both critical to your life and it is legally required that you use the correct protective equipment. Part of this PPE is the correctly rated gloves, and they must be worn correctly.
High Voltage Gloves are required by OSHA to be calibrated at first use and at least every 6 months thereafter. As the only Houston area laboratory, we can give better turnaround time on your high voltage gloves because there is minimal shipping time to other parts of Texas or to other states.
Gloves need to be cleaned, checked for any mechanical defects, checked for holes, and then for electrical withstanding voltage. Once they have passed this process, they can be marked to indicate the date this testing was performed. We start by washing the gloves in a solvent that removes surface contaminants without degrading the rubber used in the gloves. Next, the gloves are visually examined, looking for cracking and similar defects cause by incorrect storage.
Once this step is concluded we check for holes. This inflated state also allows for a secondary visual check while everything is stretched tight. To check for holes the glove is typically inflated with air and then checked to verify the air doesn’t leak out. Once a glove has passed the inflation test, it is taken to our automated electrical tester for the electrical withstanding voltage testing; first, you need to know to what Class the gloves need to be tested. For example, if you are working on a 32 kV system you need Class 4 gloves. This class is tested to 40 kV. How do you get this voltage all around the glove? The glove is filled with water to within a specified range of the top of the glove (the cuff) and this is dipped into a water bath up to the same distance from the edge of the cuff. The system ramps up the voltage until it is at the required test voltage. During this time the system constantly checks the leakage current to verify that it never exceeds the spec (if it does the testing is stopped). The 40 kV test voltage is applied to the water bath for one side of the voltage and to the water inside the glove for the other side of the voltage. This voltage is applied for a specific time (typically 60 seconds but it could be longer) and any leakage current is monitored. If the leakage current is below the maximum limit, the glove passes and is marked to indicate it passes for use at the appropriate class and the date of this test.
We have an automated system that does most of this process without human intervention, so it is very consistent in the way this calibration is performed. The gloves are dried, given a quick visual check for any damage that may have occurred during the testing process, and then carefully packed for return to the customer.
visit our laboratory today, to see our equipped facilities to help provide electrical safety in the place of work through a proper high voltage glove.