A Practical Guide to the Supply Installation Licence in Singapore 

In Singapore’s fast-paced construction and industrial sectors, one of the most frequently misunderstood compliance requirements is the Supply Installation Licence. As a practicing LEW and the director of RES Engineering Services, I’ve handled countless temporary supply setups for contractors, builders, event organizers, and facility operators who need short-term electrical power. Over the years, I realized that many clients, especially those running construction sites or temporary facilities, don’t fully understand what a Supply Installation Licence is, when it is needed, or why the Energy Market Authority (EMA) enforces this regulation so strictly.

This blog is designed to simplify the process and answer the common questions that usually arise whenever companies prepare for a temporary electrical supply.

What Exactly Is a Supply Installation Licence?

A Supply Installation Licence (commonly called SIL) is a mandatory licence issued by the Energy Market Authority for installations that require temporary electricity, not permanent building power. This licence ensures the temporary system is safe, properly supervised, and compliant before SP Group energizes the supply.

Common examples include:

• Construction sites

• Temporary workers’ quarters

• Site offices and modular cabins

• Mobile equipment

• Events, exhibitions, and temporary lighting

• Temporary generator setups

• Tunneling and infrastructure works

Any installation that is not classified as a permanent electrical system will require a Supply Installation Licence before power can be turned on.

Why Is the Supply Installation Licence Important?

Temporary installations are often more exposed to weather, movement, rough handling, and changing site conditions. These risks make safety even more important than in permanent environments.

A valid Supply Installation Licence confirms that:

• The installation has been inspected by a licensed electrical worker.

• All wiring is safe and compliant with CP5 and EMA standards.

• The earthing system is adequate.

• Protection devices are functioning.

• The load is balanced and properly sized.

• No unsafe extensions or makeshift wiring exists

• SP Group can energize the supply without hazards.

In short, the licence protects workers, machinery, and the site from electrical fires, shocks, and equipment damage.

My Process for Managing the Supply Installation Licence

At RES Engineering Services, I personally handle each step of the Supply Installation Licence application to ensure smooth approval and safe energization.

1. Site Inspection & Assessment

I begin with a full inspection of the temporary installation. This includes:

• Checking switchboards and DBs

• Verifying cable sizing and routing

• Ensuring weather-proofing and mechanical protection

• Inspecting generator connections (if applicable)

• Verifying earthing, bonding, and lightning protection

Many delays happen when installations are done without early LEW guidance. My site involvement ensures problems are identified and corrected before submission.

2. Electrical Testing

Before submitting for a Supply Installation Licence, I conduct mandatory tests such as

• Insulation resistance

• Earth continuity

• Loop impedance

• RCD/ELCB testing

• Functional checks

• Load current verification

Test results assure that the installation is safe to energize.

3. Documentation & SP Submission

I handle the entire submission process, preparing documents such as

• Test reports

• Single-line diagrams

• Load schedules

• Photos of installation

• LEW endorsement

• SP application forms

Clients appreciate not having to navigate technical documentation or EMA/SP requirements on their own.

4. Final Endorsement & Energization

Once everything is ready, I endorse the installation as safe for energization. SP will only activate the supply after receiving proper LEW verification and documentation.

This end-to-end support ensures the site receives power quickly, safely, and without unnecessary downtime.

Common Issues That Delay the Supply Installation Licence

Some frequent problems I encounter include:

• Undersized temporary cables

• Poor earthing conditions

• Exposed joints or makeshift wiring

• Missing RCD protection

• Switchboards without a proper IP rating

• Overloaded temporary DBs

• Unapproved generator connections

• Missing or outdated SLDs

With proper planning and early supervision, these can be avoided completely.

Why Clients Choose RES Engineering Services

Clients choose RES Engineering Services because they want a partner—not just a signature. I provide:

• Fast turnaround for urgent site supply needs

• In-house testing and inspection

• Direct LEW involvement (no middlemen)

• Clear communication with SP and EMA

• Accurate documentation

• Practical advice for site safety

My focus is always on keeping your site energized, safe, and on schedule.

Final Thoughts

A Supply Installation Licence is more than an administrative requirement—it’s the foundation of safe temporary power. Whether it’s a construction site, generator setup, or temporary event, proper supervision ensures reliability and safety from day one.

If you need a smooth, compliant, and fast Supply Installation Licence approval, RES Engineering Services is here to support you every step of the way.