Many UK businesses have backup generators or other forms of emergency power, particularly in critical industries such as healthcare and transport. In these sectors, maintaining a continuous source of power is essential.
Even in smaller private businesses, it’s still a smart move to have some form of contingency plan when it comes to power. If you could lose data, customers or money, or face safety risks if the power goes out, it makes a lot of sense to have a backup solution ready.
If your business has such a solution, you might feel that you’ve ticked all the right boxes. However, an emergency generator is essentially useless unless it’s regularly serviced and tested.
One of the most important maintenance tasks is known as load bank testing, which is designed to ensure your generator performs under real conditions. But what is load bank testing, how does it work, and why is it so crucial?
What Is Load Bank Testing?
Load bank testing is the process of applying an electrical load to a generator, with the aim of accurately simulating real-world operating conditions.
As for why load bank testing is so essential, it’s because it measures the ability of the generator to perform at full capacity. Without the data from these tests, you never really know for sure whether your generator is up to the task until it’s too late. The last thing you want is to find out you have an undersized or faulty generator during a power outage, when you need backup power more than ever.
Load bank tests are also needed in many industries for maintaining compliance, either with regulations, insurance requirements or both.
There are a few different types of load bank testing, including the following:
- Resistive load testing – tests at a power factor of 1.0, simulating heaters or lighting.
- Reactive load testing – tests at power factors below 1.0, simulating motors or industrial machinery
- Combined load testing – this is the most common option as it’s the closest to real-life conditions, as it combines a mix of both tests
It’s best to consult with a specialist engineer for advice on the kinds of tests that should be run on your particular system.
How Does Load Bank Testing Work?
Before you book in your generator for testing, it’s useful to know a little about how the process works. Here are the steps involved:
- Connection
The generator is connected to a load bank, which is a device designed to safely draw electrical load
- Load is applied in increments
A trained technician applies incremental loads (for example, 25%, 50%, 75% and finally 100%) to test generator performance at various levels
- Monitoring
During testing, parameters and statistics relating to voltage, frequency, fuel pressure, exhaust temperature and cooling system performance are monitored.
- Analysis
A report is produced, which ultimately reveals whether the generator can handle demand. It will also assess whether it can stabilise quickly and operate safely under stress.
Other issues may also emerge during the testing process, and these can be extremely important to know about.
For example, the test may detect problems such as wet stacking, which is the build up of unburned fuel. This creates a sludge-like substance that can cause significant damage to the generator, as well as increasing fuel consumption and emissions. It could even lead to complete engine failure in a worst-case scenario.
When Should You Schedule Load Bank Testing?
Load bank testing should be carried out at least once a year. This is a good rule of thumb for most businesses with standard power needs, although others are advised to have it carried out more frequently. For example, critical environments such as data centres and hospitals will need to have more regular tests.
You may also want to consider a more frequent testing schedule if your company is running to very tight productivity margins, such as manufacturing firms which operate 24/7, for example.
In these environments, even a few minutes of power loss could prove extremely expensive and damaging to your business. This is why it could be worth putting a few extra precautions in place to make sure that contingency plans are fully operational and ready to kick in when needed.
If anything changes in your business in terms of power-using equipment, shift patterns or anything else that can affect power demand, it’s a good idea to book in an extra load bank test to be on the safe side. This includes new installations of generators, uninterruptible power supplies (UPS) or any other power equipment.
You’ll also need to check the compliance requirements for power equipment within your industry, as these may stipulate a particular schedule for testing. One key regulation to be aware of is British Standard BS 7671, which requires electrical installations to be subject to periodic inspection and testing.
