Do All Generators Need To Be Grounded? We Find Out

Generators are essential machines, but it is vital to ensure that you safely operate them. There are many safety rules, regulations, and guidelines to follow when running a generator, one of which pertains to the grounding of the generator. Sometimes, it may be confusing to remember which generators have to be grounded and which do not. So, do all generators have to be grounded? Let us find out.

All generators have to be grounded to ensure it is safe for everybody close to the generator. Generators can be grounded in different ways, but no matter which generator you use, you have to ensure that it is grounded to avoid any hazards, such as electrocution or damaging appliances.

It is best to ground your generator. Some questions arise, however, such as why do generators have to be grounded? Does grounding work the same for all generator types? Why must generators be grounded? Additionally, how do you go about grounding your generator? These are many questions, all of which we discuss in the article below.

Do All Generators Need To Be Grounded? Let Us Find Out

When we discuss whether or not all generators have to be grounded, it is important to distinguish between different types of generators. The Occupational Safety and Health Administration established rules and guidelines to follow when it comes to the grounding of generators.

Accordingly, we will look at different types of generators and rules and guidelines that guide us in determining whether or not these generators have to be grounded.

Non-Portable Generators

When we talk about grounding a generator, we refer to the action of having its neutral conductor connected to the ground. A ground copper wire facilitates the connection to an electrode placed in the ground.

So, why is this required for generators? The answer is simple; it helps the generator deal with situations that involve power surges or voltage spikes. Additionally, it stabilizes the voltage in the system by dissipating (unnecessary excess) voltage using the earth.

Because the electrode in the ground offers very little resistance, it ensures that the path of least resistance is followed straight to the ground, i.e., the earth.

So, why must it be connected to the ground, i.e., why must it be grounded to the earth? Since the earth is very large, it has a vast capacity to ensure that electrical current dissipates. Once excess energy is directed to the ground, it is rendered harmless.

If the generator does not have this outlet, the excess energy can flow through the wires in the system and damage the appliances that are powered by the generator and overheat them.

So, as already mentioned, if you do not ground your generator, you will leave it vulnerable to voltage spikes and power surges that can occur during the regular operation of the generator.

An example of this could occur if the appliances connected to the generator are turned on or off. If this happens, it could overload the system’s wiring and damage your appliances due to voltage spikes. A worse fate is that the appliances or your generator itself can catch fire due to overheating.

Many negative consequences can result from not grounding your generator. Thus, for non-portable generators, it is safe to say that they have to be grounded if one wishes to avoid any hazards.

Portable Generators

As mentioned, non-portable generators need an electrode placed in the ground to which the generator is connected to ground it. That said, you do not always have to use one to ground your generator.

When using a portable generator, one can use guidelines to help one determine whether or not a ground electrode is required. When using a portable generator at a construction site, and:

  1. Your equipment is plugged into the receptacles of the generator.
  1. The frame of the generator has low resistance bonding with:
  • All non-current carrying parts of the generator. This can be things such as the engine, the housing, or the fuel tank.
  • The receptacle’s ground conducting terminals.
  1. It is a generator that has its neutral conductor connected to its frame – i.e., it is a neutral bonded generator.

If these three requirements are adhered to, it is not necessary to ground the portable generator with a grounding rod or any other ground electrode. If the situation meets the criteria above, the generator’s frame will act as a ground electrode.

So, we are aware of the conditions that must be present for a portable generator to be grounded without using a ground electrode. Another important question is when does a portable generator need a ground electrode to be grounded?

There are many instances in which a portable generator must be grounded with a ground electrode. We discuss two of these instances.

1. The Conditions as Stated Above Are Not Met

If the generator’s neutral conductor is part of its frame, it is a floating neutral generator. These generators are primarily standby generators for homes and some commercial offices.

In this mode, the generator connects to the neutral grounded conductor that you can find in the premise of interest’s utility service. Since this results in you failing to meet the third requirement set out in the guidelines, you must ground the portable generator with a ground electrode connected to the frame of the generator.

2. If a Structure is Powered with a Transfer Switch

In this scenario you are, most likely, using your portable generator to power a home (via a transfer switch). The transfer switch is used to transfer the power to your generator from the utility supply. This ensures that you do not have two sources that simultaneously supply power to your home: the utility and the portable generator.

If these two sources power your home simultaneously, it could be dangerous, and you should avoid it if possible. To help you manage this situation, connecting the portable generator to the ground electrode is best.

Diesel Generators

You must ground diesel generators as well since electricity leakages that may occur will put the safety of people at risk by forming a circuit with the earth.

When it comes to the function of grounding protection of diesel generators, they ensure that when electrical leakages occur (for example, when the insulation of equipment becomes damaged), the charged shell comes into contact with the human body.

Since the human body’s resistance is larger than the resistance offered by the grounding body, the current that passes through the human body is small, and the risk of electric shock is minimal if the shell is touched. Accordingly, diesel generators have to be grounded to ensure a safe operational environment.

Inverter Generators

An inverter generator is similar to a portable generator, with minor differences, such as the quality of the power it provides, the loudness of the generator, etc. These generators, however, remain generators. Their frame still grounds them, but the frame itself must also contact the ground.

You must ground an inverter generator whether it is operating or whether the power stored within the generator is being drawn (or pulled).

The Takeaway From All Of This

The takeaway from this entire section is that it has to be grounded whether you are using a non-portable or a portable generator. Sometimes generators are grounded in different ways, but that does not detract from the principle that if you have a generator operating, it must be grounded (whether by the earth itself or its metal frame).

Since the frames of your average generator are metal, it conducts electricity. If there is excess energy that strays from its normal outlets, it can flow through the metal frame and harm anyone who touches it, in addition to causing other damage. The only question remaining is how you are going to go about grounding your generator.

How To Ground Your Generator

It is clear that regardless of the generator you are operating, you must keep it grounded to ensure the safety of everyone in the surrounding area. Now we discuss how to ensure that your generator is always grounded.

The Tools You Will Need

The following tools are needed if you want to ground your generator:

  1. A copper grounding rod: This rod has been designed so that it can be placed into the ground to ensure that any electrical currents can dissipate safely. The length of the copper grounding rod that you are going to want is four feet or longer. Longer copper grounding rods are easier to drive into the ground.
  1. Copper grounding wire: This wire is used to connect the copper grounding rod to your generator’s grounding bolt. The amount of wire required varies from scenario to scenario and depends on how far your generator is located from your copper grounding rod. Accordingly, it is wise to have a bit more wire than less.
  1. A wrench, pliers, and wire strippers: The wire strippers are used to strip the grounding wire, and the pliers and the wrench are used to connect it to the copper grounding rod and the generator’s grounding bolt.
  1. A hammer (or anything similar): The hammer (or any blunt, strong tool) is used to drive the grounding wire deep into the ground. If necessary, a shovel or spike can be used as well.

The Process for Grounding a Generator

First, you are going to use the hammer to drive the copper grounding rod into the ground. The grounding copper rod must be at least eight feet into the ground. This depth ensures that if there is an electrical discharge, it will not electrocute people nearby.

After that, you have to connect the copper wires to the grounding rod. Use the wire strippers and strip anything between six and 12 inches of the insulation off the one end of the copper grounding wire. Wrap the wire around the copper grounding rod’s top with the pliers to ensure it is tight.

Finally, connect the copper grounding rod and the generator: turn your generator off and connect the grounding rod and the generator using the copper wire’s other end.

The Grounding Process For When You Go Camping

You can also use a generator when you go camping. The process is very similar to when you ground your generator under normal conditions, requiring the same tools.

First, drive the copper grounding rod eight feet (or more) into the ground with the blunt instrument – the deeper the rod, the better. If the surface is rough or hard, try pouring a bit of water on it until the ground softens up. If this does not work, try driving the copper rod into the ground at a 45-degree angle (or less).

Strip the grounding wire at both ends. Do not over strip the wire and leave too much of it open and bare. If you have the grounding rod at least eight feet into the ground, wrap one end of the grounding wire to the grounding rod with the pliers.

Finally, you can connect the other open end of the stripped wire to the generator. To do this, loosen the generator’s grounding bolt with the wrench. Wrap the wire around the bolt, and then the bolt must be re-tighten. Voila! You have now ensured that your generator is going to run safely on your camping adventure.

Tips When Grounding Your Generator

  • Make sure that the generator is dry: it is important to give special attention to making sure that your generator is dry before trying to ground it. You should not try and ground generators if you are working in wet conditions – try to find the driest spot you can. This holds for the person trying to ground it as well; make sure your hands are dry!
  • The wire and the rod: the safest option you can choose when grounding your generator is that the wire must be made of copper, and the rod should be eight feet long. Some even suggest that the rod should be made of metal, as opposed to copper. Make sure that the wire does not point in the direction where most people will be located.
  • Low resistance is key: make sure that your grounding and bonding circuits have little resistance. Some recommend that the grounding wire or grounding rod should be 0.2 ohms or less. Keep in mind that the bonding connection must be capable of electrical conduction if a short occurs.

Conclusion

Your generator has to be grounded to avoid any significant injury or other harmful events. You do not have to ground many generators in the conventional sense, such as modern generators, but most are grounded in some fashion.

A final word of advice: if you wish to be 100% sure whether or not your generator has to be grounded, make sure to check the user manual. The manufacturers of the generators themselves will be able to give you better advice than anyone else out there!

If you did not know how to ground your generator yourself, whether at a construction site or a camp, now you know!

Sources

Hubert Miles

I've been conducting home inspections since 2002. I'm a licensed Home Inspector, Certified Master Inspector (CMI), and an FHA 203k Consultant. I started PickGenerators.com to help people better understand whole-house and portable generators.

Recent Posts