Potential safety hazards and remediation measures

Hidden dangers of electricity use and remediation measures at the construction site

1.1 the construction organization design and operation are not in place

the construction site is not only a special place for electrical safety technology, but also a place where [China Plastics News] Huafeng spandex (0020 has been modified and its fire resistance reaches A2 Level) people say it has special electrical hazards. Therefore, the Ministry of construction of the people's Republic of China has specially formulated the technical code for safety of temporary electricity use on construction site (hereinafter referred to as the code), which stipulates that construction enterprises must strictly prepare the construction organization design of temporary electricity use before construction, and formulate technical measures for safe electricity use (1) heating, melting and mixing, electrical fire prevention measures, etc. However, many construction enterprises did not strictly implement the code, or did not pay attention to the problem of construction electricity, and did not seriously carry out the construction organization design work such as technical measures, safety measures, management measures, etc. This is a common problem of construction enterprises at present

1.2 it is not standard for electricians to work with certificates

few direct operation electricians on construction sites have qualifications, and they have neither obtained the electrician entry permit nor the electrician certificate for special behavior issued by relevant departments. Most electricians have not been trained in strict electrician basic knowledge and power safety knowledge. Therefore, in the actual operation, it is inevitable that the power utilization technology and safety management are not in place, and the operator's self-protection awareness of power safety is relatively weak, resulting in the occurrence of safety accidents such as electric shock casualties and electrical equipment damage

1.3 lack of monitoring of dangerous points of power consumption

construction power consumption is mostly temporary power consumption. Therefore, the safety management of the construction site is often not paid due attention to and is not in place due to its temporary nature. For example, the implementation of electricity safety system is not specific, the necessary disclosure of safe electricity use to operators is lacking, and the necessary monitoring of important dangerous operation points is lacking. Another example is the lack of operation monitoring within the safe distance between the construction site and the adjacent overhead and laid power lines, the insulation monitoring of operating manual tools and instruments in special water drenched and humid environments, and the lack of disclosure on which operation points in the project are dangerous points for power safety, and what monitoring means and protective measures need to be taken, etc. Therefore, the direct construction personnel often do not pay attention to the rules and regulations, act according to experience, go their own way, and eventually lead to disaster

1.4 leakage protector installation has loopholes

the specification strictly stipulates that the construction site must strictly implement the "three-level distribution and two-level protection" of the general distribution box, distribution box, switch box, general protector and sub protector. However, many construction sites have not installed total leakage protectors and sub leakage protectors at dangerous points of operation. Even if a few construction sites have been installed, most of them do not fully consider the over protection. According to rich practical experience and mode current analysis, the residual current, short circuit, overload protection and other specific functions of the protector, the rated action (breaking) current of the protector, under the specific environment of the installation location such as water, rain, especially wet, etc, The selection of protectors and the coordination of the level difference of action current and action (breaking) time between protectors have great randomness in installation and use, and there is no regular inspection, test jump, inspection, test and record

1.5 "three-phase five wire system" is not implemented in place

the specification clearly stipulates that TN-S neutral connection system (i.e. "three-phase five wire system") must be adopted at the construction site to distinguish the working zero line from the protective zero line, so as to ensure the safety of personnel and equipment. The current urban power consumption basically adopts the neutral point direct grounding system (TT system) of "three-phase four wire system" and the single-phase power supply system of working zero line N line and protective ground wire PE line (i.e. TN-C system). Many construction teams do not use the "three-phase five wire system" power supply as required, or because they do not understand the "three-phase five wire system" wiring method or wrong wiring, they are actually still "three-phase four wire system". And most of them have no standardized distribution rooms, and the "four ones" Regulations of "one machine, one switch, one leakage and one box" are not strictly implemented for the switch box, and they do not pay attention to the rain and moisture prevention, protection, grounding and other measures of the switch box and distribution box