Ultimate Guide for HDB rewiring Licensed Electrical Worker (LEW)

Licensed Electrical Worker (LEW) services are essential for ensuring the safety and compliance of electrical installations in residential and commercial properties. 

The two main types of LEW services discussed in this guide are LEW single line wiring endorsement and Singapore Power (SP) wiring inspection services. 

Single line wiring LEW endorsement involves certifying the Single Line Diagram (SLD) by a licensed electrical worker to ensure compliance with safety standards. 

Singapore Power (SP)wiring inspection services encompass a comprehensive assessment of the electrical wiring system by SP to verify its safety and adherence to regulatory requirements. 

These services are crucial in maintaining the integrity and safety of electrical installations. 

This guide provides valuable information for electrical workers, licensed electrician preparatory, office, and plumbing professionals.

What are the types of Licensing Electrician Rewiring Work? (LEW)

The types of Licensing Electrician Rewiring Work (LEW) are namely LEW single line wiring endorsement and Singapore Power (SP) wiring inspection services. 

LEW single line wiring endorsement involves the certification of the Single Line Diagram (SLD) by a licensed electrical worker (LEW), ensuring compliance with safety standards and approved load capacity. 

On the other hand, Singapore Power (SP) wiring inspection services encompass a comprehensive assessment of the electrical wiring system by SP, verifying its safety and adherence to regulatory requirements. 

These services play a crucial role in ensuring the integrity and safety of electrical installations in residential and commercial properties.

A) LEW single line wiring endorsement (For individual use)

The Single Line Diagram (SLD) is a crucial component of the licensing electrician rewiring work endorsement process. This diagram serves as the birth certificate for the entire wiring plan in the house, similar to a construction ISO drawing. 

It is drawn by Lito Electrical Service, a certified licensed electrical worker (LEW), confirming their expertise in installing, maintaining, commissioning, and operating electrical systems.

To certify the SLD, it is necessary to have the EMA LEW chop or stamp the diagram, along with their electrical work license number. 

The license number can be obtained from the Building and Construction Authority (BCA) website. This endorsement ensures that the electrical work meets the required safety standards and operates within the approved load. 

With practical experience and expertise, licensed electricians and LEWs are well-equipped to inspect, install, and supervise electrical services in accordance with the Electricity Act.

B) Singapore Power (SP) (wiring) inspection services (Enquire after wiring)

When it comes to ensuring the safety and compliance of electrical installations, Singapore Power (SP) offers valuable inspection services. 

Once the wiring and electric work has been completed by a licensed electrician, it is crucial to schedule an inspection with SP. 

During the inspection, SP will assess the electrical system to ensure it meets the necessary standards and regulations.

If the electrical installation passes the inspection, SP will provide a comprehensive report. This report serves an important purpose, particularly for house fire insurance. 

It documents the compliance of the electrical system with the required safety standards, giving assurance to both property owners and insurers.

It is essential to have a licensed electrician perform the preparatory electrical works before scheduling an inspection with SP. 

The electrician must be licensed by the Energy Market Authority (EMA) and possess the necessary qualifications and practical experience. 

The license number of the electrician can be obtained from the Building and Construction Authority (BCA) website.

SP's inspection services encompass a range of electrical works, including the installation, maintenance, commissioning, and operation of electrical systems. 

They are carried out by licensed electrical workers, who are classified into three classes based on their qualifications and experience. 

These licensed electrical workers inspect the electrical systems to ensure compliance with the Electricity Act and other relevant regulations.

By engaging SP's inspection services, property owners can have peace of mind knowing that their electrical systems have been inspected and approved by a reputable authority. 

This helps to ensure the safety and reliability of the electrical installations in Singapore, adhering to approved load limits and providing a secure environment for both residential and commercial properties.

What is the difference between SLD & SP testing?

Between SLD (Single Line Diagram) and SP (Singapore Power) testing, the difference is in their respective scopes and objectives. 

SLD testing focuses on verifying the accuracy and integrity of the electrical system design, ensuring that it aligns with the intended specifications and requirements. 

On the other hand, SP testing is carried out by licensed electrical workers to inspect the installed electrical systems, ensuring compliance with regulatory standards and safety measures. 

While SLD testing primarily assesses the design aspect, SP testing focuses on the physical implementation and operation of the electrical systems, prioritizing safety and reliability. 

Both types of testing play vital roles in ensuring the overall quality and compliance of electrical installations in Singapore.

1) Cost

When it comes to cost, there is a notable difference between Single Line Diagram (SLD) and Singapore Power (SP) testing. 

The cost of SLD is relatively low, typically ranging from S$350-550. This cost includes the preparation of the diagram and the necessary documentation. 

On the other hand, SP testing incurs a higher total cost, typically ranging from S$800-1100. This cost includes not only the SLD but also the fees associated with the application, submission, scheduling, and inspection required by SP. 

It's important to note that the cost for SP testing is inclusive of the SLD, making it a more comprehensive and rigorous evaluation process for electrical installations.

2) Time

When it comes to the difference between Single Line Diagram (SLD) and Singapore Power (SP) testing, the time required for each process varies significantly. 

SLD, being a simpler evaluation, typically takes around 3-4 days to complete. It involves the preparation of the diagram and the necessary documentation by a licensed electrical engineer.

On the other hand, SP testing involves a more comprehensive assessment that requires applying, submitting the necessary documents, scheduling, and inspection by Singapore Power. This process can take anywhere from 3 to 6 weeks to finalize.

It is important to note that SP testing involves more extensive procedures and checks to ensure the electrical installations meet the stringent design acceptance criteria. 

To ensure compliance and quality, it is recommended to engage the expertise of licensed electricians and electrical engineers for both SLD and SP testing services.

3) Stricter Design Acceptance Criteria

When it comes to electrical installations, ensuring compliance with stringent design acceptance criteria is crucial for safety and reliability. While both Single Line Diagram (SLD) and Singapore Power (SP) testing play significant roles in the process, there are differences in the requirements.

SLD, although important for visual representation and understanding of the electrical system, does not typically require adherence to stringent design acceptance criteria.

It serves as a blueprint that outlines the electrical components and connections but does not involve comprehensive testing or inspection.

On the other hand, SP testing entails a more rigorous process that involves extensive procedures, checks, and inspections to ensure the electrical installations meet the stringent design acceptance criteria set by Singapore Power. 

This testing is essential to ensure compliance and quality standards for electrical systems.

To fulfill the design acceptance criteria for SP testing, it is highly recommended to engage the expertise of licensed electricians and electrical engineers.

These professionals have the necessary knowledge and experience to install, maintain, and commission electrical systems in accordance with the stringent requirements.

During the SP testing, wiring inspections and material evaluations are conducted, typically with a markup of 20-30% to cover the cost of the inspection services.

This ensures that the installed wiring meets the approved load and is in line with the regulations set forth by Singapore Power.

By adhering to the stringent design acceptance criteria and engaging the services of licensed professionals, you can ensure the safety, reliability, and compliance of your electrical installations, whether it's for interior renovation design, rewiring, or power upgrades for residential or commercial buildings.

4) Building Type: Electrical Testing and Inspection

When it comes to electrical works in residential buildings for BTO/HDB projects, the need for Single Line Diagram (SLD) or Singapore Power (SP) testing depends on the nature of the electrical work being carried out. If rewiring is done in residential buildings, the SLD or SP test is optional. 

On the other hand, for commercial buildings, if rewiring is done, the SLD or SP test is compulsory. This ensures that the electrical installations meet the approved load and comply with the regulations set by Singapore Power.

In the case of landed properties, if you want to upgrade your power supply from a 63Amp single phase to a 63Amp 3-phase, SP testing is compulsory. This upgrade may be necessary if you anticipate future needs such as installing EV chargers, having more air conditioning compressors, or additional kitchen equipment. 

It's essential to note that the cost of purchasing electricity from SP for a 63Amp, 3-phase supply is approximately S$6000 - 7000 (inclusive of GST), and the lead time for the entire submission process, from start to end, for SP upgrading supply can range from 3 to 6 months. 

Additionally, for properties where the DB box was previously located inside, it now needs to be relocated outside due to regulations.

This involves coordination with the Land Transport Authority (LTA) for open road access until the front of the house (car porch), allowing SP to conduct the necessary wiring work in the meter compartment.

Internal room connections are typically handled by licensed electricians, ensuring compliance and safety throughout the process.

When it comes to electrical testing and electrical inspection, it is crucial to engage licensed professionals who possess the necessary qualifications, practical experience, and license number. 

These licensed electrical workers have the expertise to install, maintain, commission, operate, and inspect electrical systems in compliance with applicable regulations. 

By working with licensed electricians, you can ensure the safety, reliability, and compliance of your electrical installations in various LEW building types.

Who can carry out electrical works?: Electrical Installation, Testing & Inspection

A licensed electrical worker (LEW) can carry out electrical works, including new wiring, rewiring, and extensions. 

These skilled professionals undergo rigorous training and hold the necessary qualifications, such as a Technical Education Certificate, to ensure the highest standards of safety and competency.

They operate in accordance with the Electricity Act and adhere to the guidelines set by the authorities.

The licensing process for electrical workers in Singapore involves a written assessment to evaluate their knowledge and understanding of electrical installation. 

The licensing is classified into three classes, with each class having specific qualifications and experience requirements. 

This system ensures that licensed electricians are equipped to inspect, operate, and provide services related to electrical wiring and installations.

Engaging an EMA licensed electrical worker is crucial to ensure that electrical works in residential installations are carried out safely and in compliance with regulations. 

It provides peace of mind and assurance that the work is performed by a competent professional who understands the technicalities and potential risks associated with electrical installations.

What are the general rules and guidelines for wiring of residential installation?

The general rules and guidelines for wiring of residential installation include performing routine home electrical inspections to verify proper operation, inspecting switches for any signs of wear or damage, and avoiding overloading your electrical circuits to prevent potential hazards. 

Additionally, it is advisable to install an arc fault protection interrupter (ACFI) to safeguard against electrical fires caused by faulty wiring or appliances.

When undertaking DIY projects, take necessary precautions to ensure safety, such as turning off the power supply before starting any work and using appropriate personal protective equipment. 

It is essential to engage licensed electrical service providers who have a valid license issued by the Energy Market Authority (EMA) and are registered with a valid identity card number. 

These professionals should also maintain a high standard of quality in accordance with the Electricity Act and adhere to the guidelines set by the National Institute of Technical Education (NITE) for practical experience and training. 

By following these guidelines and seeking the assistance of licensed electrical engineers or electrical technician(s), you can address all your electrical needs with confidence, knowing that the installation, maintenance, and repair of your electrical systems are undertaken under proper supervision and in compliance with the regulations set by the government of Singapore.

What is the lifespan of HDB wiring?

The lifespan of HDB wiring is dependent on various factors, with the average lifespan of PVC electrical cables being approximately 25 years. However, it's important to note that the life expectancy can vary based on different variations of electrical wires and installation practices. 

To ensure the safe operation and longevity of electrical systems, it is crucial to engage professional services for the installation, inspection, and repair of electrical components. 

In Singapore, electrical works should be carried out under the supervision and commissioning of qualified electricians who adhere to the guidelines and regulations set forth by relevant authorities. 

Regular inspections and maintenance are recommended to identify any potential issues and ensure the proper functioning of the electrical system. 

When it comes to HDB wiring, it is essential to prioritize safety and engage reputable electrical services for all electrical installation and repair needs.

If you have scheduled an appointment for LEW inspection, make sure you comply with this LEW inspection checklist: What are the SP requirements & what to look out for during inspection. Also What is a licensed electrical worker (LEW) in Singapore?