Generator FAQs

Frequently Asked Questions


Choosing a generator can be a difficult and time-consuming process. There are so many generators to choose from! How do I make up my mind?

A: A generator is a machine that converts mechanical energy into electrical energy. It uses an engine to drive a generator, creating electricity.

A: There are several types of generators available, including portable generators, standby generators, and inverter generators. Portable generators are designed for outdoor or remote locations, standby generators provide backup power to homes or businesses, and inverter generators produce clean and stable energy for sensitive electronics.

A: Regular maintenance is essential to ensure your generator runs appropriately and safely. This includes checking the oil and air filters, cleaning the air intake and exhaust systems, and checking the fuel system for leaks. It’s also essential to run the generator regularly to ensure it stays in good working order.

A: Yes, generators can be used in cold weather, but it’s essential to take certain precautions to ensure that they operate correctly. This includes keeping the generator dry and well-ventilated, providing the fuel system is properly winterised, and allowing the generator to warm up before using it.

A: The lifespan of a generator can vary depending on the type and model and how well it is maintained. A well-maintained generator can last for several years, while one that needs to be adequately maintained may need to be replaced sooner.

A: Generators provide a reliable power source when the primary power source is unavailable. They can also power tools and equipment at construction sites and for recreational activities like camping and tailgating.

A: It is not recommended to use generators indoors due to the risk of carbon monoxide (CO) poisoning. CO is a colourless and odourless gas that can be deadly if inhaled in large amounts. Always use generators in well-ventilated areas, and never use them inside homes, garages, or other enclosed spaces.

A: Yes, there are regulations and guidelines for using generators. These may vary depending on your location, so you must check with your local authorities for specific regulations in your area. Some common regulations include the requirement for a permit to operate a generator and guidelines for the safe and proper use of generators.

A: Connecting a generator directly to your home’s electrical system is generally not recommended. This can create a dangerous situation in which electricity from the generator flows back into the utility power lines, potentially injuring utility workers or damaging equipment. Instead, it’s recommended to use a transfer switch, which safely and efficiently connects the generator to your home’s electrical system.

A: The noise level of a generator can vary depending on the type and model. Portable generators tend to be louder than standby generators. Look for a low-decibel rating generator or one designed to be quiet.

A: Yes, generators can be used in conjunction with solar panels. This is often done when solar panels cannot produce enough power to meet energy needs. The generator is a backup power source, providing power when the solar panels cannot produce enough.

A: The generator’s configuration is different from the main power supply. The generator is set up with a “floating earth”, whereas the main supply has an earthed neutral. Typically, it is recommended to use a personal power breaker (RCD) with the main supply. However, it is optional to use one with a generator. Personal power breakers are designed to work with the main supply. 

If it is desired to use one with a generator, the generator must be modified to match the main supply’s configuration. This simple task for a qualified electrician involves adding a link wire from the neutral terminal to the earth terminal. 

However, it is essential to note that a personal power breaker and earth spike (which connects the generator frame to the ground) must always be used once the generator has been modified. As this can be difficult to ensure, it is generally recommended not to modify the generator.

A: When using a generator as a backup power source, it is crucial to follow several safety precautions. It is essential to completely isolate the generator from the main power supply to prevent the generator from potentially powering the entire neighbourhood and to protect utility workers from electrical shock while restoring main power.

A qualified electrician should install a double-pole, break-before-make, changeover switch to accomplish this. This switch should be placed between the electricity meter and the building consumer unit. The switch allows the building to be connected to either the main power supply or a lead that can be plugged into the generator.

Many modern buildings have an RCD built into the consumer unit. This is configured to work with the main power supply’s earthed neutral and not with a generator’s floating earth. The generator must be modified to match the main power supply’s configuration to utilise this protection device. A qualified electrician can modify this by adding a link wire from the neutral terminal to the earth terminal. It is recommended to make this connection in the plug to connect to the generator, as this ensures that the generator remains safe when disconnected from the house.

The plug should be labelled “Do not connect to mains: Neutral-Earth link fitted”. The RCD does not protect the lead between the generator and the transfer switch, and it’s recommended to use a steel armoured cable for this connection. Lastly, a local low-impedance earth spike should be installed.

A: Inverter, AVR, and capacitor generators all refer to different types of generators, each with unique features and benefits.

Inverter generators are designed to produce clean, stable power suitable for sensitive electronic equipment, such as laptops, smartphones, and televisions. They use advanced inverter technology to regulate the voltage and frequency of the power output, making it more consistent and stable. Inverter generators are also known for their quiet operation and fuel efficiency.

AVR (Automatic Voltage Regulator) generators are designed to produce stable power output and protect the generator and connected appliances from voltage fluctuations. AVR generators have a built-in voltage regulating system that automatically maintains a stable voltage level. They are often used in industrial, commercial and residential applications.

Capacitor generators, also known as “capacitor-start” or “capacitor-run” generators, utilise a capacitor to help start the motor and improve the generator’s power output. This generator is typically used for heavy-duty equipment and applications, such as powering construction sites, significant events, and running power tools.

A: The best fuel type for a generator depends on several factors, including the generator’s intended use, location, and budget. Generators’ most common fuel types are gasoline, diesel, propane, and natural gas.

Diesel is a popular choice for more extensive industrial generators due to its high energy density and lower cost per unit of energy than gasoline. Diesel engines are also more fuel-efficient and last longer than gasoline engines. However, diesel is more expensive than gasoline and can be more difficult to find in some locations.

Propane is a popular choice for portable generators, particularly in rural areas where it is more readily available than gasoline or diesel. It is also a cleaner burning fuel than gasoline and diesel, which can reduce emissions and maintenance costs. However, propane tanks can be heavy and bulky, making them less convenient to transport and store.

Natural gas is prevalent for stationary generators, particularly in commercial and industrial settings. It is a clean-burning fuel and can be piped directly into a building, eliminating the need to store or transport fuel. However, natural gas generators are typically more expensive than other fuel types and may need to be more practical for remote or mobile applications.

A: The noise level generated by a generator depends on several factors, including the generator’s size, fuel type, and design. Generally, smaller portable generators tend to be noisier than larger, stationary generators. Gasoline-powered generators are typically louder than diesel-powered ones, and open-frame generators are noisier than enclosed or soundproofed ones.

It’s worth noting that when comparing the noise level of different generators, the manufacturer’s specifications should be taken with a grain of salt as they vary based on the environment, operating conditions, and maintenance. It’s also important to note that the generator’s noise level is affected by the distance between the generator, the operator, and the surrounding environment.

A: Whether to buy an electric or diesel generator depends on several factors, including the intended use, location, and budget.

Electric generators are powered by electricity and are generally quieter, cleaner, and more fuel-efficient than diesel generators. They are also typically smaller, lighter, and more portable, making them a good option for residential or light commercial use. They are also suitable for sensitive electronic equipment that can be affected by the harmonic distortion and voltage fluctuation caused by some internal combustion engines.

On the other hand, diesel generators are powered by diesel fuel and are generally larger and more powerful than electric generators. They are typically more durable and have a longer lifespan than electric generators. They are also more fuel-efficient than gasoline generators, making them a more cost-effective option for long-term use. They are also more suitable for heavy-duty industrial and commercial use, where power continuity and reliability are critical.

Electric generators are typically more expensive than diesel generators, but they are cheaper to operate and maintain in the long run. On the other hand, diesel generators are less expensive upfront but more costly to operate and support and emit more pollutants.

In summary, whether to buy an electric or diesel generator depends on several factors, including the intended use, location, and budget. 

Electric generators are generally quieter, cleaner, and more fuel-efficient, making them suitable for residential or light commercial use. Diesel generators are usually more extensive and powerful, making them ideal for heavy-duty industrial and commercial use. Electric generators are typically more expensive than diesel generators, but they are cheaper to operate and maintain in the long run.

Underloading Diesel Generator 

What is it? 

To operate a diesel engine under minimal or no load. Also called “wet-stacking” in the biz jargon.

This is because either the data centre wants to preserve the warranty on its UPS batteries, or the facility manager wants to avoid disrupting everyday operations by transferring the genuine load to the generator.

The generator may have been overspecified at the time of purchase, or the business may have reduced its power needs.

How can I avoid it? 

When choosing a new generator, selecting one appropriate for your needs is important without being excessively large. If the generator is designed with extra capacity or the current installation has more power than required, it is essential to implement a load bank testing program.

The load bank should simulate a demand between 75% and 100% of the prime load. This will help burn off carbon deposits and prolong the generator’s life.

It is generally recommended to run the generator at 75% of its prime power for 2 hours every 100 hours.

If you have any questions or concerns about generator underloading or misuse, don’t hesitate to contact our Technical Sales team for further clarification.

Why is it a problem? 

For a diesel engine to perform at its best, it must be operating under a significant load. If it fails to reach its optimal operating temperature, a portion of the fuel will go unburnt and can lead to a buildup of soot. This soot can cause internal glazing of the cylinder bores, sticking of the piston rings, and a decrease in compression. Additionally, the injectors may accumulate carbon, resulting in more unburnt fuel entering the combustion chamber and the exhaust.

One of this problem’s first signs is thick smoke from the exhaust. Over time, the unburnt fuel will condense in the exhaust and mix with the soot, creating a dark liquid similar to engine oil. This liquid will leak from the exhaust, appearing as an oil leak. This liquid can build up in the exhaust silencer, and there is a risk of it catching fire from the increased heat of the exhaust fumes if the generator is subsequently used under full load.

If a generator is consistently operated with no or minimal load, it can lead to permanent engine damage.