Electrician is one of the most dangerous professions. In order to maximize the safety of personnel, the company provides it with protective clothing and shoes with protection against electric arc. To this, personal protective equipment (PPE) and a professional power tool are also issued. Particular attention is paid to work under voltage and at height. For this, workers are provided with additional equipment with protective properties from an electric arc. These include safety harnesses, stepladders, rugs. One of the interesting devices that can be attributed to personal protective equipment and tools is an insulating rod.
What is she doing? This type of equipment allows you to work with electrical installations that are energized, but not more than 550 kV. Depending on the functionality, these tools are divided into two main types. There is an operational and measuring rod. We will consider their features later in our article.
Design Features
The tool is a handle, which can be divided into three segments. This is a handle, insulating, as well as a working part. Such an instrument for an electrician can be precast or telescopic. The main thing is to provide the insulating element with strong link grip.
For this, special metal fasteners can be used, but their total length should not exceed five percent of the length of the insulating part.
The working tip is made of metal or some dielectric material and, depending on the purpose, can have a different shape and functionality.
The insulating part is made of materials that do not conduct current. For example, it can be hard rubber, bakelite, wood and others. By technology, they are carefully boiled in linseed or hemp oil, dried. After that, the material is coated with an insulating varnish on top to protect it from moisture penetrating inside.
The handle is most often made of the same material as the insulating part. Between these sections a restrictive ring should be arranged, which during operation will prevent the contact of the hand and the insulating section. The limiter must protrude at least ten millimeters and have a height of at least three millimeters.
The total length of the rod according to state standard number 20494-2001 ("Insulating operational rods and portable grounding elements - technical conditions") depends on the voltage of the electrical installation on which the work is performed.
In installations with a voltage of more than 350 kV, tools are used for the work of two electricians, using a supporting device.
main parameters
The weight of equipment for one person should not exceed eight kilograms. The force on one arm for measuring rods should not exceed 80N, for other types up to 160N. The length of the insulating part and the handle depends on the voltage, according to GOST 20494-2001.
The scope of the elements
Performance of work under voltage with the help of a rod can be carried out in closed electrical installations, or on the street, but in dry weather. In no case should you use this device in rainy, snowy weather or during fog, drizzle.
Under such weather conditions, there is a high risk of electric shock, which in some cases can lead to fatal consequences.
Using this tool, operations are performed with disconnectors, changing fuses, installing parts of arresters, checking insulation on power lines and substations, applying portable grounding, using it as a means of freeing an injured person from electric current, and performing measurement work.
Modifications and capabilities of each type should be considered in more detail.
Operational bar
There are four types of basic functionality:
- SHO (operational isolation). It is used for a large number of works due to the replaceable head. Applied on electrical installations with voltage up to 220 kV with direct or alternating current.
- SCO (rescue). With its help, you can rescue a person from the affected area with a voltage of up to 110 kV. Emergency release measures increase the chances of resuscitating the victim.
- SHOW (universal insulating bar). It is used on electrical installations similar to SHO. At the same time, the maximum number of replaceable working parts increases the functionality.
- ShZP (grounding). Also used in electrical installations with voltages up to 220 kV with direct or alternating current. This device allows you to approach areas with residual voltage or partial shutdown of the installation. Due to work with SHZP the number of electric injuries is significantly reduced.
The operational bar allows you to perform the necessary work under tension. This eliminates the risk of electric shock. The main thing is to follow the rules for the operation, inspection and testing of PPE.
"Ticks"
A separate position is to isolate ticks. The element allows the replacement of fuses in electrical installations up to 1 kV and higher. They are also used to remove heads, fences in installations up to 350 kV inclusive.
It is allowed to replace this type of equipment with a universal operational bar, with an appropriate working head.
The size and weight of this equipment should ensure comfortable operation for one person. The insulating part and the handle should be made of materials with dielectric and antistatic properties.
The mites themselves can be made of electrically insulating materials or metal. Oil-resistant tubes must be worn on metal sponges so as not to damage the surface of the cartridges during operation.
The length of the insulating tongs also depends on the magnitude of the voltage:
- At voltages from 1-10 kV, the length of the insulating section is 450 mm, and the handles are 150 mm.
- At voltages from 10-35 kV, the length of the insulating section is 750 mm, and the handles are 200 mm.
Measuring
Using this professional power tool, it became possible to determine surges, voltage drop in parts of the electrical installation, which is in normal operating mode. Two methods are distinguished: by measuring the temperature of the contacts or by directly measuring the power surges.
The measuring head is a spark gap configured in the laboratory. The minimum allowed value is set. The working head through parallel connection to the test site, using indicators, indicates the presence or absence of voltage. It is important that at the time of monitoring the electrical installation is in normal operating mode.
Three main types can be distinguished:
- SHIU. This device provides the ability to change the distance between the electrodes, which allows you to most accurately obtain measurement data.
- SHI. In such devices, a pointer microammeter is installed with an additional resistance of up to 160 megohms. Depending on the measurement method, the set of probes with conductors that are connected to the clamps changes on the working section. The probes are placed on a controlled insulator, parallel connection occurs. The arrow of the microammeter indicates the result of measurements.
The SI device is also used for the second method. The probes are installed to measure the temperature at the contacts.
- Electrical measuring pliers. It is a current transformer with a detachable magnetic circuit. For the primary winding, a conductor with a measured current is used, and the secondary is shorted to the measuring device either arrow or digital.
Operating conditions
The insulating rod should be used in an external environment with a temperature regime from minus 45 ° to plus 40 ° at a relative humidity of 98% at 25 ° .
The use of devices is not allowed:
- Not having the appropriate certificates, and not having passed the test, respectively, not meeting the safety standards.
- Malfunctioning. Such devices must be repaired. After which the tests were conducted. And only according to the data received, a decision is made on the further use or disposal of the device.
- With high humidity. In wet weather.
- Using supports (stepladders) for measuring work.
Work on electrical installations is permitted to workers with appropriate approvals. Each employee should be equipped with a full set of PPE, including dielectric gloves, dielectric bots, protective clothing with electric arc protection, safety glasses and a respirator. All this will help protect the employee from electrical injuries as much as possible.
Before work, the insulating rod must be subjected to visual inspection.
If a malfunction is detected, it must be replaced by another instance.
During operation, mechanical tests are not carried out. Planned and unscheduled can be carried out in the event of the fall of the device, the detection of flaws. Previously, the device is subjected to repair.
Testing
Since work on an electrical installation is classified as hazardous, a tool for an electrician is subjected to careful inspection and control. Moreover, depending on the equipment, tests are carried out at the manufacturing plant. According to GOST 20494-2001 they can be:
- Acceptance. Spend for each product.
- Periodic. Each bar must be exposed.
- Typical. Three samples of the same species are selectively tested. All types of testing will be required.
All test activities are carried out by the manufacturer with the help of specially trained people who have a certain level of tolerance and who have been trained and certified.
These operations must be completed in a timely manner; the life and safety of an electrician's health depend on this.
Test list:
- Visual control. Checking the completeness, marking, packaging. The presence of the required documentation and compliance with the required safety are checked.
- Verification of compliance with factory drawings. Produced using measuring tools, there should be a complete coincidence of the parameters.
- Checking the electrical insulation for strength. They produce AC voltage of industrial frequency with a single application for no more than five minutes. In this case, the voltage increase to 1/3 of the value can be arbitrary. Further increase should be smooth. The working and insulating parts of the rod are checked. If it is not possible to conduct a test with a full measuring section, then this part of the rod is checked by segments. If breakdowns, local heating from dielectric losses, surface discharges are not detected, then it is considered that the product successfully passed the test.
- Tensile test. One end of the rod is fixed, the other with the help of a load or a winch is subjected to an allowable load. The test was successful in the absence of visible damage.
- Bending test. The product is fixed horizontally at two points at the restrictive ring and the end of the handles. The boom sample was tested in the absence of visible damage.
- Checking the greatest effort on hand. The horizontally fixed rod is fastened with two points - the front (50 mm from the limit ring) and rear (50 mm from the end of the handle) supports. Measurement is made on the front support and the indicator should not exceed 160N. Insulating rod up to 1000V is not subjected to this type of test.
If the result is negative, repeat the procedure with a large number of samples. If the data is repeated, the entire type of product is seized and the release of a new batch is prohibited until the causes of negative indicators are clarified and eliminated. In such situations, the test stamp is crossed out by a red line.
All tests are carried out in accordance with applicable standards.
For operational devices, tests are performed once every two years, for measuring devices - once a year.
Equipment selection
In order for the employee to be provided with the right PPE and tool, the relevant state standards and norms should be studied. This will help to choose the right kit for each type of work.
The price set on insulating rods will play an important role for the consumer in the matter of choosing a fixture. On average, it is 500 rubles. But do not chase cheap devices. You should carefully study the warranty obligations of the manufacturer and the package of documents provided to them. All products must pass pre-sale tests and have the appropriate stamp.
Total
In conclusion, I would like to note that the modern world does not imagine itself without electricity. And that means you cannot do without measuring rods.
It is hard to imagine what would happen if the power supply was cut off worldwide. Probably there will be chaos and panic. Therefore, you should pay great respect and respect to people servicing electrical installations, and the relevant authorities to provide them with all necessary personal protective equipment as much as possible.
So, we found out what constitutes such a technical tool as an insulating rod.