High voltage safety
Safety issues are an absolute priority when dealing with any high voltage product. To ensure the maximum level of safety for both company personnel and the customer, we proceed from the principle that there is no “safe” high voltage level. From this point of view, we consider any situation associated with the presence of high voltage as dangerous and posing a threat to life.
High voltage safety
We strongly recommend using protective Faraday cages, means of blocking access to any panels where high voltage may be present, using grounded rods to discharge high-voltage sources, external blocking circuits, and avoiding touching any parts of the circuit that have even the slightest possibility of contact with high voltage. Strict adherence to all safety regulations is the best guarantee of safe work.
To reduce the risk of electric shock, a number of measures are used, the main of which are: protective grounding; zeroing; insulation of live parts; use of insulating pads, rubber gloves, rugs, etc.
Protective grounding is a special connection to the ground of the enclosures of electrical machines and devices that may be energized. Protective grounding is done to reduce the voltage between ground and the unit's frame to a safe value. In the event of a breakdown of insulation between the phase and the casing of the installation, the current passing through the person is not dangerous. Protective grounding consists of an earthing switch (metal structures in the ground) and grounding conductors (steel or copper buses connecting the unit's housings to the earthing switch, which are welded or bolted to them).
Zeroing is the connection of the cases of electrical machines and devices that may be energized, not with the ground, but with a neutral wire. This leads to the fact that the short circuit of any of the phases to the body of the device or machine turns into a short circuit of this phase with a neutral wire. The short-circuit current triggers the protection and the damaged installation is shut down. The neutral wire should not have fuses and switches.
The danger of electric shock increases sharply in the presence of high humidity, high temperature, process dust, etc. Depending on this, the premises in which the electrical equipment is installed are divided into dry (temperature 27-30 ° C and humidity up to 60%), wet (humidity not more than 75%), damp (humidity above 75%), especially damp (humidity about 100%) and hot (temperature for a long time more than 30-35 ° C).
The peculiarity of the building material of the floors has a great influence on the working safety conditions in rooms with electrical equipment. A floor with a sufficiently high resistance (wood, asphalt) is especially dangerous, and a floor with a lower resistance (concrete, stone) is less dangerous.
The most complete safety precautions for working with high voltages are presented in an extract from the IEEE standard known as "The IEEE Recommended Practices for Safety in High Voltage and High Power Testing."
We strongly recommend using external electrical interlocks. An external interlock is a chain designed for customer use. Most of these circuits have two terminals located on a custom connector. To transfer the source to the "high voltage on" state, these two points must be closed. It is highly recommended to switch them using failsafe electromechanical elements (switches, contactors, relays) rather than semiconductor (transistor) components. If at the moment of breaking the connection between the specified points, the source was in the "high voltage on" (HV ON) state, then it will go into the HV OFF mode (high voltage off).
With this simple chain, an external interlock device can be connected to the source, the contact elements of which can be placed on the high voltage panel. If the panel is accidentally opened, the high voltage will be disconnected; this greatly reduces the risk of injury. Use blocking chains as often as possible.
It should be noted that only qualified, specially trained personnel who are familiar with all the potential hazards of high voltage are allowed to work with high voltage power supplies.
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