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Electrical tests are the foundation for electric-related safety. They ensure that the electrical infrastructure is installed appropriately and everything is working as intended without the chance of failure.
These systems require periodic maintenance where a certified electrician will visit the property, conduct tests, and highlight and fix known faults.
However, you may have noticed that not all electricians provide the same results. Why does this happen? Is there any one result that you can depend on to ensure maximum safety?
The truth is that these differences are inherent to the nature of electricity and the components used to supply it. These variations don’t stem from competence but from the realities of electrical testing in the real world. Since multiple variables play a role, the test results can vary from one electrician to another.
Read on to find out all about electrical testing, how it is conducted, and why electrical test results vary between electricians:
The variance in tests can be confusing for homeowners and property owners. They can vary from one electrician to another, but they don’t happen because one electrician is better than the other.
It rather happens due to variables during the time of testing. We’ll cover these variables in a bit. Let’s first highlight an analogy that can help you understand the test results better.
You can think of electrical tests in the same way as the medical tests you would get done to gauge your health.
If you get tested for cholesterol, for example, in the medical report, you will get a result and a reference range.
This range accounts for all the normal variances that can cause the test result to change. Typically, if your result falls between the reference range, this means that your test results are normal.
Some people might have a result that sits at the very start, middle, or the very end of the range, but if you do not report any symptoms, then the report will be accepted as normal. In fact, it is even possible (and normal) to get different readings if you get two of the same tests done at the same time.
In the same way, electrical tests are conducted with reference ranges in mind. These ranges account for variables that can cause the result to fluctuate. If the results are within the range and there is no apparent sign of electrical problems, the report will be acceptable, and your installation will be deemed safe.
Electrical testing is not a simple pass or fail, but it is about analysing data and determining if it fits within the acceptable range.
Under BS 7671 IET Wiring Regulations, most results are in ranges and are not to be taken as absolutes.
For example:
As you can see, there are several conditions and ranges for tests, which is why you can expect normal variation when you get your electrical infrastructure tested.
Why does this variance occur? Well, the building itself is to blame.
Let us explain.
Variables such as the temperature, moisture level, load on circuits, length of cabling, age of wiring, and other appliances plugged in can inherently change the test readings.
Here is how each variable affects the reading:
So, merely conducting the test in the morning vs at night or during a wet or dry day can affect the final test results.
Variance can also occur due to the type of equipment used. All certified technicians use compliant hardware to test electrical systems in the UK; however, each manufacturer’s equipment can have an acceptable range of variance, even if they use all the compliance requirements during manufacturing.
This is just the nature of all electrical equipment, which is why test equipment is also allowed to vary.
However, this variance is also regulated. According to UK law, tolerance on calibrated meters is allowed a +/- variance of about 5%.
What does this mean in plain English? Well, if two electricians using two perfectly calibrated testers conduct the same tests, they can get slightly different numbers.
Electrical test results can also vary due to the methods used to test the electrical system.
According to BS 7671, electricians are allowed to use multiple valid ways to test electrical systems.
For example, Earth Loop Impedance can be tested by:
All of these methods are valid, and their test results are acceptable or compliant for testing, but they may produce different values or results.
We have explained how variance can occur due to variables, testing methods, and even the type of hardware used for testing.
However, the main conflict in testing occurs when it’s time to interpret the data from the tests. This is where human reasoning and risk assessment come in.
The Electrical Installation Condition Report (EICR) involves judgment and interpretation. It is a risk assessment of your electrical infrastructure conducted by an electrician who may have different risk interpretations.
For example, two electricians can see the same result but legally code it differently in the EICR. A slightly higher impedance can be marked as C3 by one and C2 by the other.
C3 refers to something that needs to be improved, while C2 is for something potentially dangerous. In both cases, you will need to monitor the impedance, but how they are interpreted in the report is different.
These interpretations are professional opinions on measurements, and because raw data from numbers is converted into English text, one electrician might interpret results differently from the other.
Now that you know how variance occurs and how results are interpreted, let’s take a look at when variance can be a problem.
The goal of employers and landlords isn’t to have a perfect installation but a SAFE one.
Perfection in electrical equipment means nothing, which is why manufacturers and installers work to instead build and install components as per the regulations and guidelines so that they are within acceptable variances.
However, variance can be an issue when there is a huge discrepancy between two electricians. For example, one electrician may show that your system is A-okay, while the other may say that there are problems in the system.
This is a rare situation, but one that demands immediate attention. Results can vary, but they can’t vary so much that they fall off the reference ranges.
In this case, you will need to ask for measured values and not just codes in the EICR. You will also have to compare the results from previous tests or have a third opinion from a certified installation company.
Many comprehensive electrical installation companies, such as Calder Electrical, use industry-standard best practices and employ certified and highly qualified technicians who use multiple test points to determine the result of a component.
This can reduce the chance of errors in the final testing value and can help you understand the true “health” of your electrical infrastructure.
All electrical tests involve a certified electrician conducting a series of tests to identify and address potential issues. These tests are done as per electrical safety standards.
Electrical testing is mandatory for all types of residential, commercial, and industrial properties as it makes the electrical system efficient, extends its lifespan, and helps minimise risk and costs.
In the UK, the guidelines and frequency for testing are outlined in the Wiring Regulations BS 7671.
For example, residential properties, including homes, must conduct a detailed inspection of the electrical system every 5 to 10 years, or if you are selling the property.
There are several types of tests, some of which we have highlighted above. They include:
These tests can have variances (within acceptable ranges) and are done to check the components according to three core categories:
These tests reveal results that are noted and interpreted in the EICR report, which the property owner can use to take further action. For example, if the result indicates multiple fails or marks the component as C2, then you will need to take immediate remedial action to ensure the safety of the property and its occupants.
Electrical tests don’t just reveal problems, but they can also hint towards areas that can be improved to increase efficiency.
Here are some of the ways to increase the electrical efficiency of your property:
The best thing you can do to improve efficiency is to schedule a test and have a professional inspect your system to identify safety hazards. Testing itself is a great first step because it can automatically help you reveal the areas that you need to focus on.
Electrical equipment is prone to depreciation and damage over time. With time, wiring in your property may deteriorate and become outdated, causing inefficiencies.
Something as small as old wiring can lead to increased energy consumption, higher costs, overheating, voltage drops, and resistance. All these factors can affect efficiency.
If the wiring in and around your property is old, electricians may suggest that you invest in modern copper wiring, which can improve safety and energy efficiency.
Technology refreshes every couple of years. This refresh also brings efficiency. For example, upgrading to energy-efficient LED lighting is a simple way to make a huge impact on energy consumption.
Replacing traditional incandescent and halogen bulbs with energy-efficient LED lights is a great way to improve your property’s energy efficiency. LEDs use up to 90% less energy than incandescent lights and can save quite a bit on electricity bills every year.
You must also opt for using inverter-based appliances that can toggle the energy use of the appliance according to its load. Inverter-based fridges, motors, and ACs can significantly cut down on energy expenditure and help extend the life of the appliance and save money.
Smart systems are becoming the norm in the modern world and for good reason. These systems use sensors to detect loads and can use monitoring equipment to give you real-time data that you can use to make better energy choices.
Some great options to consider include smart thermostats, smart appliances, smart home wiring, smart controls, smart meters, and smart lights.
These devices use Internet of Things or IoT technology that can enable them to connect to the internet and provide you with the convenience of remotely controlling them via a smartphone app.
Modern smart devices can also use Artificial Intelligence (AI) to monitor the usage of the appliance and adjust its load accordingly. Smart appliances such as smart refrigerators, washing machines, and dryers are all designed keeping energy efficiency in mind and can significantly increase the life of your electrical system by adjusting load requirements.
Solar power offers renewable energy for residential and commercial properties. They are a great option for people who are looking for efficiency and better savings.
While solar systems can have a high initial cost, they offer a great Return on Investment (ROI) and have little maintenance along with a long lifespan. They can ensure that your property gets clean and stable energy without the risk of fluctuations that may damage your electrical system over time.
These systems have a separate range of tests that are conducted by professionals, and investing in them can be a smart idea if you want maximum efficiency and safety for your property.
Calder Electrical has been providing electrical services to residential, commercial, and industrial properties for over 40 years, and we are specialists in all aspects of electrical installations, maintenance, testing, and energy-saving practices.
We offer a wide range of services to meet the demands of our clients. 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.
We understand the importance of reducing your energy consumption, which will not only help lower your bills but also allow you to play your part in reducing harmful carbon emissions.
Our energy-saving services include installing smart systems for lighting and heating, installing or upgrading to energy-efficient products such as LED lighting, a wide range of smart home solutions, solar panel installation, and ways to maximise an existing solar PV or wind turbine installation so that you can store excess energy rather than feeding it back into the grid.
Contact us here or call us at 0800 612 3001 for a detailed discussion on electrical testing and why electrical test results vary between electricians.
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