TEST LABORATORY FOR LIVE WORKING TOOLS, ELECTRICAL SAFETY EQUIPMENT AND INSULATED AERIAL DEVICES
At Kolab Ensayos we have a separate laboratory for testing different types of electrical safety equipment.
How and where do we carry out dielectric tests on live working tools, electrical safety equipment and insulated aerial devices?
Testing can be carried out either at Kolab or at the client’s facilities
At Kolab Ensayos we have a separate laboratory where we test different electrical safety equipment in compliance with the respective applicable standards. Just like the insulating rubber gloves, all equipment sent to Kolab for testing is given a KL serial number, which will be indicated in the Test Certificate, together with that specific item’s characteristics, and the test result (PASS/FAIL). After testing, a sticker is affixed on every piece of protective equipment, indicating the KL number and the test date.
Tests can be carried out either at Kolab or at the client’s facilities, which requires sending out a mobile test unit and setting up a portable test lab. Every piece of equipment undergoes prior visual inspection to verify that they are in good condition and have all the markings required by the applicable standard (rated working voltage, electrical hazard double-triangle symbol, name of manufacturer, etc.).
What are the main testing services provided by Kolab Ensayos?
In addition to insulated rubber gloves, Kolab Ensayos also provides a dielectric testing service for other types of tools and protective equipment used for electrical work, which also require maintenance and testing. These include:
Insulating Stools (UNE 204001 Standard)
The test consists in placing the stool on a grounded metal plate and placing another metal plate, acting as an electrode, on top. The specified test voltage for the stool’s voltage class is then applied. If the leakage current is within admissible levels, the stool is considered to have passed the test.
Dielectric Footwear (UNE-EN 50321 Standard)
Boots or overshoes are tested in the same way as dielectric gloves, by partially immersing them in water and partially filling them with water. An electrode is then inserted in the water inside the item and the applicable test voltage is applied. All footwear undergoes prior visual inspection to verify its condition.
Insulated Jumpers (ASTM F2321 Standard)
The insulated jumper is suspended by its end clamps from a chain hanging from a busbar and immersed in a grounded water tank. The specified test voltage is applied according to the jumper’s rated voltage for 1 minute to check the voltage withstand capability of the jumper’s insulating jacket.
Rigid Insulating Covers (UNE EN 61229 Standard) and Flexible Line Hose (UNE EN 61479 Standard)
Protective covers are placed over conductors or other items (disconnect switches, insulators, etc…) and their purpose is to protect workers against accidental contact with adjacent phase conductors (at different potential). They are tested by applying the specified test voltage inside them by means of a metal bar, and wrapping a grounded metal gauze around them. If they withstand the test voltage for one minute without puncturing, they are considered to have passed the test.
Voltage detectors (UNE EN 61243 Standard)
Voltage detectors alert workers to the presence of voltage in a system considered to be de-energised. The detector, fitted onto the end of an insulated hotstick, is placed near the voltage source, and this is raised until the detector emits a visual and sound alarm. The voltage at which the unit starts to detect voltage (threshold voltage) is noted and checked against the range of values specified by the applicable standard.
Insulating Blankets (UNE 61112) and Insulating Mats (UNE 61111)
Blankets serve the same purpose as protective covers, but are used for parts of an electrical system for which no suitably shaped cover is available. Mats serve a similar purpose to insulated stools. For testing, the blanket/mat is placed on a grounded metal plate and a second plate is placed on top. The top plate is raised to the test voltage specified by the applicable standard, which is held for one minute. If no puncturing occurs, the item is considered to have passed the test.
Hotsticks (UNE EN 60832 and other standards):
Hotsticks (insulated poles) are hollow tubes of epoxy resin-reinforced fibreglass, filled with insulating foam. Different types of hotsticks are fitted with a head or ferrule featuring a tool or accessory to perform a certain task (rescue hook, disconnect prong, ratchet wrench, grip-all clamp, wire holder clamp, etc.). They are tested by applying 100 kV by means of a spring that distributes the voltage around their circumference, and placing a grounded spring at the other end of the tested section. The resulting leakage current must not exceed the value specified by the applicable standard. Kolab Ensayos also offers an insulated live working tool repair service
Insulated Ladders (UNE EN 61478, UNE EN 50528)
Insulating ladders may be high voltage or low voltage. Ladders for barehand work (high voltage) allow a linesman wearing a conductive suit to approach the line and bond on to the phase conductor, while remaining insulated from ground potential. They are tested by sections, in a similar fashion to hotsticks. Kolab Ensayos also provides a barehand work ladder repair service, for ladders with broken rungs or requiring surface reconditioning.
Temporary Grounding Sets (UNE EN 61230)
These sets provide personal protection to individuals working on a de-energised system, protecting them against electrical risks caused by accidental re-energisation, induced voltages or other causes. They provide an alternative path to ground of lower resistance than the worker’s body, so that most of the current will flow through them rather than through the worker. Ground cable size varies according to the system’s rated voltage. Testing consists in verifying the integrity of connections to end clamps and checking the electrical continuity of the entire assembly.
Barehand Suits (UNE EN 60895)
These are conductive suits that use the Faraday cage effect to protect linemen when they become electrically bonded to a conductor, approaching it from an insulating structure such as an Epoxiglas ladder or an insulated aerial device. Verification consists in visual inspection (seams, absence of tears, etc.) and checking for electrical continuity.
Insulated Aerial Devices for Live-Line Work (UNE EN 204005 IN, UNE 61057)
Aerial devices with an insulated platform (bucket) and insulated boom, mounted on a truck or track vehicle. Their dielectric integrity is checked by visual inspection of the platforms (buckets) and inner liners and the surface of the boom insulating sections, and by applying the specified voltage at the upper boom tip (first step) and across the ends of the lower boom fiberglass insert (second step). In both cases, the leakage current must not exceed throughout the duration of the test the maximum value specified for the voltage category (A, B or C) of the aerial device.
As indicated earlier, we also offer the possibility of performing these tests at our clients’ facilities. This is done using a mobile test unit to carry all the equipment and materials and perform the desired tests at an extremely reasonable price.
