Are you still making these electrical design mistakes?

Construction design drawing is the premise to ensure the stability and safety of building construction, and is a crucial measure to prevent from happening. With the rapid development of the construction industry today, its importance is also increasing. It is precisely because of the strict inspection of construction drawing that the construction quality is kept stable, which effectively avoids the occurrence of safety hazards and quality accidents and safeguards the interests of the general public.

This paper analyzes several aspects of electrical construction drawing examination and verification, mainly involving power supply and distribution system drawing examination and verification, fire equipment distribution, lightning protection grounding design, lighting design, etc.

High - pressure system diagram review common fault

1. Whether the primary wiring diagram of high voltage is reasonable; Has the consent of the power supply authority been obtained?

2. There is no special metering cabinet.

3. Whether the standard drawing is correct.

4. Whether the relay protection mode is reasonable; Is the setting calculation and selectivity correct?

5. Whether the connection of incoming, outgoing, contact, voltage transformer, metering and other circuits is correct.

6. Whether the secondary wiring diagram is correct, whether the terminal wiring diagram is complete, whether the incoming line, contact and other security blocking device.

7. Whether the specifications and models of high-voltage cables are correct; Whether the thermal stability problem is taken into account, and whether it is calculated.

8. Whether the specifications and models of the hV bus are selected correctly; The choice of high voltage electric appliance and switch cabinet are in accord.

9. Whether the instrument is fully equipped and the specifications and models of ammeter and current transformer are correct.

10. Whether the specifications and models of voltage transformers and circuit breakers meet the requirements of the high-voltage switch cabinet?

Low - pressure system diagram review common problems

1. Whether the breaking capacity of main switch and outlet circuit switch can meet the requirements.

2. Whether the transformer is suitable for matching with ammeter and watt-hour meter.

3. Whether the installation of low-voltage bus is reasonable and whether there is any problem when entering the switch cabinet.

4. Whether the transformer capacity calculation is correct and the capacitor compensation is appropriate.

5. Whether the distribution circuit is calculated, and whether the wire specification and model are wrong.

6. Whether the selection of the protection switch and the fit of the conductor are correct, and what is the selectivity between the upper and lower levels?

7. Whether the protection and measurement meet the requirements of the specification, and the provisions of the power supply department.

The fault power system diagram review diagram is common

1. Whether the generator is automatically started and automatically switched.

2. Whether the layout of generator room meets the specification requirements.

3. Whether the generator room has ventilation and smoke exhaust equipment, how to deal with the installation of fuel tank, and whether it meets the requirements; Whether the storage capacity meets the requirements of the local fire department; How to solve the oil depot.

4, substation fire alarm and how to solve the fire, whether there is gas fire extinguishing facilities, whether to meet the requirements of the code.

5. How to solve the smoke exhaust of the generator in the basement and whether it can meet the requirements of smoke exhaust and air exhaust?

6, generator noise, vibration isolation how to solve, whether to take measures.

Power system chart review is common

1. Whether the protection of the power system is correct and whether the wire specification is compatible.

2. Whether the wire specification and pipe diameter of each branch and each section (that is, from the distribution box to the first section of the distribution box) are clearly marked.

3. How to solve the problem of small switch and connection of main line?

4. Whether the switches, fuses and other specifications and capacities of distribution box branches have been clearly marked.

5. Whether the output switch capacity of the distribution box branch has been clearly marked.

6. Loop number, whether the pipeline specification has been specified.

7. Whether the wire and pipe diameter match correctly.

Lightning protection grounding design explains related problems

1. Whether the classification of lightning protection is correct and whether the drawings are specified.

2. What is the required value of grounding resistance? Is there any explanation?

3, material anticorrosion, galvanized whether there are requirements, there is no description.

4. Whether the conductor (including steel bar) is connected by welding, and whether there is any explanation.

Flash connection design problem

1, lightning belt material, such as round steel or flat steel specification is appropriate.

2, lightning rod height and support installation is reliable.

3. Whether the installation of lightning belt on parapet, cornice and roof ridge is reliable.

4, lightning belt across the settlement joints, expansion joints and other appropriate practices.

5. Whether it is reliable to use steel roof truss and iron roof to connect the flash device.

6. Whether the metal parts high above the roof, such as ventilator, flagstaff, masts, lamp posts, water tank and cooling tower are reliably connected with the lightning protection device.

7, parallel with the festival lights, lightning belt height is higher than the festival lights.

Standard practice of referrals

1. Whether the root number and distance of lead-off line meet the requirements of the specification.

2. When the longitudinal main reinforcement of the column is used as lead off line, whether the connection of the reinforcement meets the specification requirements and whether the welding length is required.

3. Whether the open lead downline is reliably connected with other parallel metal pipes, such as downpipes and breathable pipes.

4. Whether the root of the lead off line with open installation is protected by threading.

5. Whether the open or dark installation leads are made with broken wire clips, and whether it affects the appearance of the building.

6. Test clips were made by using column reinforcement for lead off line, and whether the number of positions was reasonable.

7, anti lateral lightning strike whether to do the cage type lightning protection measures.

Summary of grounding device design and installation problems

1. Whether grounding and zero connection have been fully considered, and whether there is repeated grounding of the incoming line.

2. Programmable telephone, programmable elevator, computer room, fire control center, control center, audio center, etc., whether an independent grounding system is needed and whether the grounding resistance meets the requirements.

3, in the same electrical system whether there is zero and ground mixed phenomenon.

4, lamps, switching equipment, electrical equipment and other outer skin, safety protection grounding is reliable, grounding connection is meet the requirements.

5. Whether the metal shell of all pipes, cabinets, boxes and other electrical equipment is reliably grounded.

6, there is no anti-static measures, whether reliable.

7. Whether the materials and specifications of the artificial grounding body meet the requirements and whether the anti-corrosion treatment is reliable.

8. Whether the number of artificial earthing bodies meets the requirements, how to deal with the soil with high resistivity, and whether it is reliable.

9. Whether there is a natural grounding body nearby and whether it is fully utilized.

10. Whether the main reinforcement is welded when the foundation plate and beam are used as the grounding body.

11. Whether the elevation and position of external reinforcement are appropriate; Whether the phenomenon through the waterproof layer, how to deal with, whether reliable, there is no explanation.

12. Whether the gate is equipped with equalizing pressure or insulation measures.

13. Whether the embedment depth of grounding body meets the requirements of the code.

There are common problems in the examination of lighting plan

1. Whether the direction and position of the power supply are reasonable, whether the phase number is appropriate, and whether it has been indicated on the figure.

2. Whether there is an incoming line master switch, and whether the loop number and wire specification have been indicated.

3. Whether the height of overhead inlet line can meet the specification requirements, and whether the power and lighting are separately mounted.

4. Whether the location of the distribution box is appropriate, whether the light and dark installation is appropriate, and whether the adjustment location and size have been required.

5. Whether the load of each phase is balanced, whether the capacity of single channel is appropriate, and whether the number of each street lamp head meets the specification requirements.

6. Whether the branch length is appropriate, whether the voltage drop can meet the requirements of the specification, and whether it is calculated.

7. Whether the number of wires is wrong, and whether the number of wires is reasonable with the pipe diameter.

8. Whether the laying method of pipelines is reasonable and whether the explicit wiring and the implicit wiring are consistent with the structural form.

9. Whether the accident lighting meets the requirements, how to solve the power supply, and whether there are omissions in the lamp cap line and switch line.

10, local lighting installation height, use voltage, wire section, etc. Is reasonable.

11. Are the specifications, models, installation methods, installation height and number of bulbs clearly marked?

12. Whether the installation details of non-standard lamps and lanterns are complete and whether the lamps and lanterns with decoration requirements have been specified.

13. Whether the illuminance is appropriate, whether it is calculated, and whether it meets the requirements.

There is a common problem in the lighting system

1. Whether the distribution box model, number, code and capacity are clearly marked.

2. Whether the number, code, section and pipe diameter of the incoming cable in the distribution box have been clearly marked.

3. Whether the cable or conductor specification and pipe diameter from distribution box to distribution box have been indicated.

4. Whether the switch (or breaker) conductor diameter of the distribution box branch circuit has been clearly marked.

5. How to solve the wiring problem of large-section cable and DE6 type switch?

6. What is the selectivity of switch protection at all levels and whether it meets the requirements?

Accident lighting is common in drawing examination

1. Whether the emergency lighting power supply is reliable, and whether the automatic switching device is at the end.

2. Whether the corridors and evacuation exits are equipped with evacuation indicator lights.

3. Whether the location distance and installation height of the evacuation lights are appropriate.

4. Whether the illuminance of the battery-operated lamps meets the requirements.

There is a common problem in lighting control system

1. Whether the position of the lighting switch is appropriate, and whether it is convenient to turn on and off the light.

2. Whether the corridor and staircase are double-control switches and whether the number of control wires is wrong.

3. Is the control of lamps decentralized or centralized? Is it reasonable?

4. Whether the control schematic diagram is reasonable if there are requirements for dimming and dimming.

It is a common fault that fire equipment does not adopt separate power supply circuit design

The elimination and non-elimination of common distribution lines and distribution boxes. Such as:

1. All kinds of fans have mixed names and mixed lines.

2. When the elimination control room and the weak current center are used together, the power supply is also used together.

3. Connect the roof fire control pump to the lighting box.

4. Connect the drainage pump at the bottom of the ladder to the distribution box of the life pump.

5. Connect the drainage pump of the elimination pump room to the non-fire fighting power supply.

6, connect the small capacity exhaust fan on the distribution box of smoke control and exhaust fan (do not benefit small, do not cheat small).

7. Connect the power supply of the fire alarm device to the lighting box nearby.