"Mandatory Provisions of Engineering Construction Standards" (housing construction part) (hereinafter referred to as "Provisions") has been issued for more than a year, and construction drawing review agencies in various places have also carried out review work one after another. Undoubtedly, this work will play an important role in improving design quality and ensuring engineering construction safety. As the "provision" has risen to the high degree of enforcement of laws and regulations, it is also closely related to the survival and development of design units and the technical career of designers, so it has attracted great attention from the design community. At the second session of the fifth session of the Standing Committee, the Electrical Professional Committee of the Provincial Civil Engineering Society organized all the Standing Committee members to study the provisions in depth, communicated the common diseases and common faults found in the review work in various places, and also expressed their opinions and heated discussions on controversial issues, reaching a preliminary understanding. Recently, the executive director of Fuzhou and some examiners exchanged views again at a small-scale meeting. Everyone agreed that it is necessary to publish the collected common problems that violate the "provisions" in the construction drawing review, so as to play a warning role and prevent similar mistakes from repeating. I analyze, summarize and sort out the common problems, and combine my own experience in the review work as follows. Due to the level and space, I don't do too much development, but just touch on it. The inadequacies only represent my personal opinions. Welcome to correct me.

(1) "The power load should be graded" (Article 2.1.1 of the "Provisions" GB51152-95)

1. The design document should explain the building area, height and use of the building, and determine its nature, fire protection category and power load level; It should not only be generally stated that the whole building is designed according to a certain level of load, but also that all power loads should be classified.

2. Load classification errors are common:

(1) For department stores, exhibition buildings and public buildings with a height of less than 24m and an area of more than 3111m2 per floor, the outdoor fire water consumption exceeds 25l/s.. "Code for Fire Protection Design of Buildings" GBJ16-87 stipulates that its fire-fighting electrical equipment shall be supplied with power according to the secondary load, and the designer has not looked up the relevant code or communicated with the building and water supply and drainage specialty, and thinks that it is a low-rise building, so it is blindly classified as the tertiary load;

(2) The same specification stipulates that the fire-fighting power load of factories and warehouses whose outdoor fire-fighting water consumption exceeds 31L/S should be Class II, but it is wrongly classified as Class III load;

(3) The kitchen power and cold storage in the first-class and second-class hotels belong to the first-class load, but they are designed according to the third-class load;

(4) Class I and Class II high-rise buildings are classified according to the habit of 51 meters height, without paying attention to their purpose and nature. For example, for an eight-story hospital with a height of 32 meters, or a comprehensive building with an area of over 1111m2 and a height of 28 meters, its fire power load should be classified as Class I but classified as Class II, and so on.

(2) power supply for class I load (GB51152-95, paragraph 2.1.2)

1. The "Provisions" stipulate that class I load should be supplied by two power sources, which is generally clear to designers. The main problem lies in the fact that many engineering substations are not designed synchronously or are "entrusted separately", and some areas simply stipulate that all substations of 11KV and below are supplied by power. In this case, the designer should put forward clear technical requirements for the power supply level. If only the terminal design is done, the entrusted party will blindly design according to the conventional system and cannot meet the load level requirements. The comparison in place can give the main connection mode of power supply and distribution system supplemented by the operation mode description, or classify each circuit according to load grade and power supply requirements in the form of a list.

2. For a class of high-rise buildings, when the diesel generator is selected as the second power supply of the first-class load, the design should clearly require that the diesel generator is equipped with a self-starting device and can supply power within 31S, so as to meet the requirements of "High Code" for fire protection design to supply power according to the first-class power supply.

3. When two power sources of a class of high-rise buildings are led from two feeders of a nearby switch station, it should be clear that the two power sources at the upper level of the switch station come from two different power plants or two regional substations.

(3) About the problem that "the emergency power supply and the normal power supply must take anti-misoperation measures". (Article 3.1.2 of the "Provisions" GB51152-95)

1. The design documents shall have relevant descriptions of the measures to prevent wrong juxtaposition and the design contents of the drawings.

2. The design should not simply state that "anti-misoperation measures should be taken". For the first-class load, special attention should be paid to expressing the self-starting conditions of the diesel generator, the electrical and mechanical interlocking conditions between the main switches, and the accessories that the main switches must be equipped with. The interlocking relationship between them should be given if the key switch is used for mechanical interlocking.

3. According to the interpretation of "Article", it is required that the self-starting signal of diesel generator should be taken from the auxiliary contact of the main switch of normal power supply, and not only from the voltage loss signal of the secondary circuit of the incoming voltage transformer on the high voltage side. (Examination consulting engineer)