A Comprehensive Guide to Commercial Electrical Testing Procedures

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Commercial Electrical Testing

Electrical installations done by professional installers have an exceedingly positive outlook in terms of longevity, efficiency, and most importantly, safety.

But what makes these systems so foolproof and efficient in the first place? Well, the answer to this has to do with the strict standards that certified electricians follow to ensure the integrity of a power installation in a commercial or private space.

One of the foundations of these standards is rigorous testing that ensures maximum efficiency and safety. In this guide, we will look at the various commercial testing procedures and the importance of following compliance in commercial electrical installations.


Electrical installations are highly complex tasks that require quite a lot of knowledge and experience. When done correctly, an electrical installation works in harmony with all the equipment installed within the system to provide maximum efficiency and peace of mind.

For example, when you plug a high-voltage appliance into a socket, the appliance draws power according to its wattage. If the load of the appliance is beyond the capacity of the socket or the fuse leading into the main power box at the property, it may result in a breaker failure or worse, it may damage the appliance.

However, professional installers take these scenarios into account and install high-capacity sockets with high-load fuses to counter any such problems. This type of electrical equipment is installed after rigorous testing by a certified professional who uses experience and strict testing procedures to identify potential problem areas.

In the same way, for commercial properties, the installer will first conduct a thorough survey and identify the overall power needs within the premises of the property. For example, an area within the property that handles heavy machinery might require extensive high-capacity or load-balancing electrical equipment. Once the survey is completed, the team will then begin the work accordingly.

During the electrical inspection and testing process, a certified professional, such as the ones at Calder Electrical will:


The only way to ensure the safety of an electrical installation in a commercial space is to have it checked out by a professional electrician. These electricians are the only trained and experienced personnel to handle testing procedures using the British Standards.

However, how do you know when you need to run these tests?

As per the wiring regulations BS 7671:2018, every commercial property’s electrical installations must be regularly inspected and tested every 5 to 10 years to rule out any defective electrical work and safety hazards.

This means that if your electrical installation is around or beyond the five-year mark, you should call in a professional as per their provided schedule to have the system checked for faults.

The reason why you do thorough testing after some time is because of wear and tear. No matter how well the installation was initially done, the equipment used in the installation will be subject to the test of time.

In other words, all electrical equipment depreciates over time and can wear down or accumulate damage over the years. When this happens, even a small fault as an exposed wire or a loose connection could potentially jeopardise the entire system.

Testing is also part of the regulations.

If you are a landlord who is renting out the property, you will be held responsible for the testing of the electrics as per the wiring regulations for commercial properties and businesses. Testing can also be carried out when a new tenant comes in to ensure the safety of the electrical equipment.

Please keep in mind that testing procedures add to the intrinsic value of the property. Businesses are usually busy places where a lot of people visit daily. This means that if the system is flawed, you might potentially be putting multiple lives at risk.

For example, if you are a landlord that doesn’t get the electrics checked and if an electrical-induced fire is caused, then the overall value of the property may go down – or worse, the reputation of the property may be impacted. However, by ensuring that you follow regulations, you can provide tenants peace of mind, ensure the longevity of the property, and avoid any type of risk associated with electrical damage!

This is especially important if you wish to sell your property in the future. Any potential buyer will demand an Electrical Installation Certificate (EIC) that proves the quality and the maintenance schedule of the electrical installation.

So, what are some of the important tests for commercial properties? Continue reading to find out!


Commercial electrical inspection covers a few important procedures that give the installer a good idea about the scope of work and the level of damage within the system.

The most basic one is a visual test that even property owners can conduct on their own! For example, property owners can detect faults in lighting systems, sockets, fans, ACs, appliances, machinery, or any other equipment connected to the main power line.

Here are a few common warning signs of a failing electrical system (or one that requires attention):

  • Flickering lights.
  • Excessive circuit breaker tripping, especially when powering on high-wattage equipment.
  • Sparks, burning, and discolouration near the power outlets.
  • A burning odour or distinct burning smell when powering on equipment.
  • Frayed wires and electrical shocks.
  • Broken sockets that won’t fully insert plugs.
  • Broken switches that won’t fully go to the “on” position.

If you notice some or all of the signs mentioned above, it is probably time to call in the cavalry. These warning signs may not look alarming but they can quickly lead to problems which is why it is recommended that the property owner gets in touch with a professional and certified electrical team as soon as possible.

Here are some of the most important commercial electrical testing procedures:

Visual Inspection

As mentioned above, one of the most basic ways to start electrical testing is to go with the old-fashioned visual inspection.

Please keep in mind that the differences between the visual inspection conducted by an unprofessional vs a professional will be huge! For example, you may conduct a visual inspection on your own, however, when a professional looks at circuits or equipment around the premises, they will use their experience to detect warning signs that you may easily miss.

For example, a loose rocker switch or a damaged socket board for a high-wattage appliance could quickly cause a lot of damage if not fixed – this type of scenario may be a non-issue for someone who is not well-versed with electrical equipment, but for a certified installer, it is grounds for immediate action.

During the visual inspection, a certified electrician will make notes and create a Visual Inspection Report (VIR) to provide an overall general summary of the health of the electrical system. This report is great for an overall outlook on the efficiency and effectiveness of the system.

Electrical Installation Condition Report

This is where things get more detailed! An Electrical Installation Condition Report (EICR) is the holy grail of testing procedures because it can help outline potential flaws in the system and provide a full look into the efficiency of an electrical installation.

Previously known as the Periodic Inspection Report (PIR), this tool can be used to conduct a thorough assessment of all electrical systems within the commercial property.

The EICR assesses the current condition of multiple systems using multiple tests. For example, the report will cover aspects of the electrical wiring, accessories, equipment, and any other component connected to the main line in the property.

An EICR is generated using functional testing where every electrical component is thoroughly checked and documented. This documentation can also help the electrician in creating an effective testing and maintenance schedule.

The benefit of Electrical Installation Condition Reports is that they are conducted at regular intervals and provide a holistic view of the system. So, even if a problem shows up after the inspection, you can rest assured that it will be caught and fixed during the next inspection.

Insulation Resistance Testing

Insulation resistance testing is an important testing procedure that checks the effectiveness and efficiency of the wiring in an electrical installation. Resistance is what allows current to flow effectively as per the load required to run equipment connected to the power line. However, if there is a fault in the resistance of the wiring, you can face severe consequences like electric shocks, and even fire.

This test is conducted by certified electricians using a high-quality and specialised tester that runs several sub-tests that confirm the effectiveness of the wiring during high load.

Earthing Tests

Testing the earthing system is vital in avoiding shocks, fires, and damage to the electrical system. This test ensures that all exposed conductive parts are fully connected to the earthing system within the commercial property.

If there is a problem with earthing, then you will likely feel an electrical shock (the severity of which could vary) when you touch an exposed conductive part of any appliance. A certified tester will carefully conduct a thorough analysis of the earthing system and highlight any current or potential problems within the system.

RCD Testing

Residual Current Device testing is an integral part of not just testing an electrical system but also ensuring its safety. An RCD test checks the safety devices installed within the system that trip, or in other words, disconnect the power to a socket during a power fluctuation.

These devices are integral in ensuring the safety of the device and can prevent shocks, fires, and even damage to electrical equipment. A certified installer will use specialised testers to check these devices and make sure that they are working as expected.

For example, the testing can reveal the lag time between the electrical imbalance and the shut-off of the circuit. A long lag or delay would indicate that the system isn’t working properly and needs fixing!

The combination of these tests can provide you with a comprehensive overview of your current installation. Once the testing is complete, the team will share the results with you and provide their recommendations.

We highly recommend that you go with professional installers who can provide all the services under one roof. Not every company offers testing, installing, procuring, and maintenance services. However, veteran companies like Calder Electrical are more than equipped to provide commercial property owners with peace of mind!


The only way to ensure the integrity of your current or new electrical installation is to go with a reliable and certified electrician who is experienced and trained to perform electrical tests.

Here are a few ways to get the right certified electrician for your electrical installations, testing, maintenance, and inspections:

  • Go to the Competent Persons Register – a database of the Competent Person Schemes (CPS) – and run a search using the name of the person or business you’re looking for. Try typing “Calder Electrical” and you’ll see it listed under the NICEIC registered businesses.
  • Do a thorough cost-benefit analysis. We recommend that you check the reviews of the installer to ensure that they are experienced and have great reviews on their professionalism, service, and after-service.
  • We recommend that you talk with the professional service team before the work begins so that both you (the property owner) and the team (installers) are on the same page when it comes to the testing of the installation. Professional installers, like Calder Electrical, always keep commercial property owners in the loop so that they know exactly what to expect from the visit.
  • Make sure that the electrician working on your property is insured and holds liability for any damages or unexpected incidents happening during the inspection. Calder Electrical provides fully trained and highly experienced individuals who perform their duties using the latest regulations to keep you safe from not just hardware problems, but also important legalities.


We have been providing electrical services to residential, commercial, and industrial properties for over 40 years and are specialists in all aspects of electrical installations, maintenance, and testing.

All our work is fully insured, and we work to meet the standards set by the NICEIC to make sure all your electrical installations meet the current regulations and all the notifiable work is signed off by the local authorities.

If you have unplanned issues within your home or business, we can provide a call-out service to rectify and solve any problems such as circuit tripping, loss of power, broken items that need repairing, or to check if you feel something is unsafe or a potential hazard.

Our team can generate a Visual Inspection Report (VIR) to identify anything visual that does not comply with the standards or looks unsafe, as well as a full Electrical Installation Condition Report (EICR) where we will identify and test each circuit to make sure they are not deteriorating and are safe for use within the current standards and regulations set by the BS 7671.

We can also provide PAT testing of appliances to make sure that any items such as kettles, computers, and microwaves are safe for use in the home and workplace.

Contact us here or call us at 0800 612 3001 to get in touch with our professional electricians for more information on commercial electrical testing procedures.

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