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Do Commercial Lighting Circuits Need RCD Protection?

Ensuring your building’s commercial lighting circuits meet the required standard is part of your obligation to protect customers, employees and other visitors. Part of this obligation is the installation of the Residual Current Device (RCD).


In many cases, business owners don’t know whether these safety devices are required to protect against electric shocks and fires due to earth faults. For this, we look to the 18th Edition Wiring Regulations.


Let’s discuss everything you must know about RCD protection on lighting circuits.

RCD protection on lighting circuits: Explained

RCDs are safety switches designed to protect people from electrical shocks. Since electrocution can be deadly, especially when dealing with high-powered commercial circuits, RCDs are a common feature of practically every lighting solution. At Wells Electrical Contractors, we install them as standard.

Like any safety device, RCDs are effective but not 100% foolproof. It’s not uncommon for building owners to install but fail to check them regularly, leading to failed electrical safety audits. This is why the Health and Safety Executive (HSE) receives around 1,000 reports of burns and shocks annually.

Sadly, around 30 of them are fatal.

It underpins the importance of installing RCDs and instituting regular checks to ensure they’re still functioning.

Which circuits need RCD protection?

RCDs detect leaks that could cause electric shock. Conventional electrical currents are intended to travel via select conduits. When there’s a leak, electrical power can leave these conduits, creating a shock hazard for unsuspecting people.

An RCD detects these leaks and automatically disconnects the power source to reduce the risk of a shock. They’re not 100% effective against shocks, but even when shocks do happen, RCDs reduce the intensity, which could save somebody’s life.


But does this also apply to commercial lighting circuits?


The answer is yes. They won’t stop a blown circuit, but if your lighting is regularly shutting down, it indicates a problem with your circuitry. However, RCDs will prevent intense electric shocks.

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Is RCD protection legally required for commercial lighting?

All commercial lighting circuits supplying lighting fixtures are required to have RCD protection in place. Moreover, RCDs can only be installed by a fully qualified contractor within a commercial environment.

Although some people may install them using their DIY skills at home, this isn’t allowed in a commercial setting. This is why our clients turn to Wells Electrical Contractors - we’re a NICEIC-approved contractor with a full set of qualifications for each of our trained electrical engineers.

Wiring regulations for commercial property owners

RCD protection is often a confusing subject generally for businesses. We often refer to the 18th Edition Wiring Regulations, or BS 7671, because this is the Bible for using RCDs in the commercial world.

While socket outlets rated up to 32A in places like kitchens and bathrooms always need RCD protection, lighting circuits are an outlier because there are no exceptions. You always need RCD protection for any lighting circuits indoors and outdoors.


But what if you read that these regulations aren’t legally binding?

This is true. None of these regulations are by themselves legally binding and cannot be enforced by law. On the other hand, compliance with them is required to comply with rules that are legally binding.

For example, BS 7671 compliance is needed in England and Wales to meet Part P of the Building Regulations. Likewise, the Electricity at Work Regulations 1989 refers directly to BS 7671.

In other words, you can’t be taken to court due to non-compliance with BS 7671, but non-compliance with that means you’re failing compliance with other legally binding legislation.

On a side note, it’s important to mention that BS 7671 is also used by other parties, including safety assessors and insurers. For example, if there’s a fire or severe electric shock on your premises, your insurance will likely be null and void if it was found you didn’t have RCDs installed on your lighting circuits.

Wiring regulations for commercial property owners


Commercial property owners need to bear two things in mind:


1. All lighting circuits must have RCDs installed.

2. All RCDs must be installed by a qualified electrician.

But an RCD isn’t a bog-standard product you can install once and then forget about. Your legal requirements extend beyond the installation stage. Let’s discuss the three points you must know.


Choosing the right RCD


RCDs are not a one-size-fits-all product. Compliance means choosing the appropriate RCD for the appropriate circuit, which differs between businesses, whether hotels, shopping centres, or factories.


Some examples of factors to consider include:


  • Location

  • System type

  • Load type


Maintenance and Inspection


The biggest mistake businesses make is not inspecting or regularly testing their RCDs once installed. These processes are essential for ensuring they operate safely and efficiently for years to come.


Again, the 18th Edition Wiring Regulations have specific sections outlining precisely what must be done to maintain RCDs.




Like other aspects of your electrical infrastructure, RCDs must undergo regular testing to confirm that they are fit for purpose.

It’s recommended that RCDs are tested at least every three months as standard. Furthermore, additional tests are recommended after making any changes or repairs to your electrical system. Again, this is something only a qualified electrician is permitted to do.


RCDs protect commercial lighting circuits, but you must have the right RCDs installed, maintained and tested by a professional. Regardless of your electrical knowledge, handling any aspect yourself means automatic non-compliance and all the consequences that come with that.


Partner with an electrical company you can trust, like Wells Electrical Contractors. We support the UK’s businesses in ensuring their electrical circuits perform at their best while being safe to use. To learn more about our commercial electrical services, contact our team today.

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With a combined 65 years’ experience working nationwide, Wells Electrical Contractors are experts in electrical installation, maintenance and energy saving from conception to hand over in each project. Our engineers deliver the best electrical solutions to businesses in the UK and Ireland.

We understand that no two customers’ electrical needs are the same, and when it comes to making important decisions on upgrades, emergency repairs or installations, the more information you have the better. That’s why we offer a comprehensive range of solutions, as well as the knowledge to help customers make the right decisions.

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