Basic knowledge of electrical safety for charging stations

Basic knowledge of electrical safety for EV charging stations

I. The hazards of electric shock

1. Electric shock (electrocution): This refers to the passage of power through the interior of the body, affecting the normal function of the heart, lungs and nervous system. Electric shock can be divided into direct contact electric shock and indirect contact electric shock.  

2. Electrical injury (burn): is the electric current through the body can cause burns to the skin, muscles, or organs inside the body. Electrical injuries can be divided into the following types - electrical burns, electrical branding, mechanical injuries, and electro-optic eyes.

3. Fire and Explosion: Electric currents in abnormal or faulty conditions generate high temperatures, enough to ignite objects near the point of ignition, resulting in fire and explosion accidents. General causes of high temperatures include - electrical overload; damaged insulators, short circuits; inadequate maintenance of electrical appliances or wires; poor ventilation.

II. Basic measures to prevent electric shock during work on low voltage equipment

1. Completely disconnect all aspects of the power supply from the equipment to be de-energised, including the neutral line, and remove the fusible fuse and hang a ‗no closing, someone is working' sign on the operating handle of the cutter or switch; if necessary, install grounding wires on both sides of the cutter or switch or send someone to guard the site.   

2. Before work, a qualified test pen must be used to test the power to the outage equipment and surrounding equipment.   

3. Work to prevent accidental touching, accidental touching of the adjacent live equipment and measures to prevent short-circuiting of live equipment.   

4. Take measures to prevent accidental entry into adjacent live intervals and accidental boarding on adjacent live poles and towers. 

5. Prohibit the use of shouting and appointment of time for stopping and delivering power. Arrange commanders and guardians according to the needs of the site.

6. According to the work needs and site conditions to take other security measures.

III. The basic requirements of the electrically charged operation

1. Electricity work should be carried out by experienced electricians. At least two people should work at the same time, with a special guardian for supervision.   

2. Working with electricity should be carried out with qualified insulating tools and on dry insulating materials.  

3. The work with electricity should be taken to prevent phase short circuit and three single-phase grounding insulation measures. Take measures to prevent accidental contact and accidental touching of the surrounding low-voltage live body.   

4. When working first divided into the fire line, zero line, choose a good working position. Disconnect the line, first disconnect the fire wire, then disconnect the ground; lap the wire, the reverse order. The human body should not touch two wires at the same time.

IV. Electrical safety appliances

Safety appliances can be divided into two kinds of basic insulation safety auxiliary insulation safety appliances. Basic insulation safety gear is the degree of insulation is sufficient to resist the operating voltage of electrical equipment and direct contact with the power supply safety gear. Auxiliary insulated safety appliances refers to insulation strength is not enough to resist the operating voltage of electrical equipment, and does not directly contact the power supply safety appliances. Before using safety equipment, the appearance and function of the equipment should be verified, and auxiliary insulated safety equipment must be used when using basic insulated safety equipment.   

The following is a list of common safety appliances.

High-voltage basic insulation safety equipment: insulating poles, insulating clamps, high voltage testers (high voltage test pens)   

Low-voltage basic insulation safety equipment: insulated gloves, tools with insulated handles, low-voltage test pens    

High-voltage auxiliary insulation safety equipment: insulated boots, insulated gloves, insulated mats and insulated tables

V. Storage methods for common safety equipment

Safety equipment should be stored in a dry, ventilated place. Insulated ties should be hung or placed on a stand and should not be in contact with the ground or wall to prevent moisture; insulated gloves should be stored in a closed cabinet and stored separately from other tools and instruments; high-voltage testers should be placed in a moisture-proof box and stored in a dry place. Insulated boots should be stored in a cupboard and should not be used in place of normal rain boots. All safety equipment should not be used as general work.

VI. Zero grounding protection

The main purpose is to provide a low impedance path for the fault current to discharge after earthing when there is a leakage situation. That is, when the electric shock, the current to ground flow away and avoid entering the human body to cause injury.  

Zero: the metal shell of the equipment and the protection of the zero line connection, when a phase directly connected to the metal shell of the equipment, that is, the formation of a single-phase short circuit, short-circuit current prompted the line on the short-circuit protection device quickly, within the specified time will be the fault equipment disconnected from the power supply to eliminate the risk of electric shock.

Luoyang Grasen Power Technology Co., Ltd is a professional AC home charger and DC fast charger EV supercharger manufacturer for 11 years in China, the charging connectors can be any two of CCS1/CCS2/CHAdeMO/GBT. Please enter our website for more information: https://www.grasen.com. Please send email to sales@grasen.com for inquiry.