How to Ground your Portable Generator

Portable generators give you the freedom of electricity on the go. That means you can take the comforts of home with you camping, electrify outdoor events, power tools at a remote worksite, and more.

While portable generators are relatively safe compared to other motor-driven tools, there are still some important safety considerations to keep in mind. One of the most important of these is recognizing whether your generator needs to be grounded and understanding how to do it.

Not all portable generators need to be grounded, and some may only need to be grounded in specific circumstances. In this article, we’ll cover what grounding is, how to tell if you need to ground your portable generator, and explain how to do it safely.

Understanding Electrical Grounding

When electricity is flowing through a set of wires, it is always seeking to dissipate energy by returning to a ground. In a normal electrical system, like that of your generator, electricity flows through “hot” wires to a series of neutral wires.

But, if anything happens to that normal electrical circuit, electricity will flow through the path of least resistance. If your generator isn’t grounded, that path of least resistance could allow electricity to flow in places it shouldn’t be – which can cause electrocution, spark a fire, or cause other dangerous situations.

Grounding provides a backup path of least resistance for electricity to flow. The term grounding is used because in many electrical systems, that backup path leads directly into the ground where it can pose relatively little risk.

Do You Need to Ground Your Portable Generator?

All portable generators need to be grounded in order to be safe. But, whether you need to do anything special to ground your generator depends on how it was designed.

Most modern portable generators are designed such that the metal frame around the generator acts as the path of least electrical resistance. In this case, the engine, fuel tank, and generator housing are all bonded to the frame, so that any electricity flowing through the generator outside of the wiring is grounded by the frame.

The easiest way to tell if your generator needs to be grounded is to check your owner’s manual. The manufacturer should provide extremely clear instructions on whether or not your generator needs to be grounded.

If you don’t have the manual or it is not clear, you can also inspect the construction of your generator. If the generator’s transfer switch gives you the option to transfer current to a neutral ground conductor, your generator’s components consist of a separately derived system. This means you will need to connect your generator to a separate grounding rod.

How to Ground Your Portable Generator

If you find that you need to ground your portable generator, you’ll need to wire your generator’s transfer switch to a grounding rod.

Tools and Equipment To Ground Your Generator

You’ll need to have the following equipment on hand to ground your generator:

  • Copper Grounding Rod – A copper grounding rod is designed to be driven into the ground, where any electrical current can be safely dissipated. For most portable generators, you’ll need a copper grounding rod that is at least four feet in length, although a longer rod can make driving it deeper into the ground easier.
  • Copper Grounding Wire – Copper grounding wire will be used to connect the grounding bolt on your generator to the grounding rod. The amount of wire that you need will depend on the distance between your generator and your buried rod. Be sure to give yourself some extra wire since this can make driving the rod into the ground easier.
  • Wire Strippers, Pliers, and Wrench – These tools will be used to strip the copper grounding wire and to connect it to the grounding rod and your generator’s grounding bolt.
  • Hammer or Mallet – You’ll need a heavy, blunt object to drive the copper grounding wire into the ground. Depending on the terrain, a shovel or spike may also come in handy.

Step 1: Hammer in the Copper Grounding Rod

The copper grounding rod should be hammered into the ground or buried at least 8 feet deep (although you can buy a 4 foot rod, but 8 is standard for home installations). This depth ensures that any electrical discharge from the grounding rod won’t electrocute people standing on the surface. If you are in rocky or difficult terrain, the rod can be hammered in at an angle of up to 45 degrees.

Step 2: Connect Copper Wire to Grounding Rod

Use your wire strippers to strip out about six to 12 inches of insulation off one end of the copper wire. Then wrap this around the top of the grounding rod, using your pliers to make sure it is wound tightly around the rod.

Step 3: Connect the Generator to the Grounding Rod

You can connect your generator to the grounding rod using the other end of your copper wire. The generator should be turned off when you do this.

Locate the grounding bolt on your generator and loosen the nut slightly. Strip the end of the copper wire one to two inches and then wrap it around the grounding bolt with your pliers. When done, tighten the nut to ensure the wire remains firmly in place.

Should You Ground Your Generator?

Most modern generators are designed as a single system, such that the frame serves to ground the generator. But, if you find that your generator requires an external ground, grounding it properly is an extremely important part of safe generator operation.

Grounding your portable generator can be fast and simple once you have the right tools on hand. Once it’s grounded, you can operate your generator without worrying about potential electrocution in the event of an electrical failure.

22 thoughts on “How to Ground your Portable Generator”

  1. My Predator generator (4375 starting watts) will be sitting in a shed that is 15 feet away from an electrical outlet on the side of my house. The outlet is grounded via the house electrical system. Instead of pounding a copper rod into the ground could I just connect a copper wire to the ground prong of a 3-prong “dummy” plug (nothing connected to the hot or neutral prongs) and then just plug it into the outlet? Would that count as an appropriate ground for my generator? Thanks for your opinion on this.

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  2. How do I sink a 4 foot rod 8 feet into the ground? I live in Northern California, where the adobe is hard and full of stones. Even if I could somehow dig a 4-foot post-hole, I could never drive a rod into the ground from there because the stones would block its path. (I recently broke a steely mattock head just trying to dig a hole to plant flowers!) My new Predator 3500 generator unequivocally says it needs to be grounded. What should I do?

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      • Sorry, I also live in Northern CA, and agree with the person asking the question. Driving it in in any direction is not an option. Digging a 3’ hole took me over a week with pick ax & other tools, and was only possible when the water table dropped a specific depth and before it dropped any farther. That was in the least rocky part of my property. So, without heavy machinery, and only if a wide surface is dug, is anything but a T-post put into the ground (then requiring special equipment to remove if you need to, since the earth has turned to cement for most of the year). So, any suggestions for other options?

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    • Try connecting to the ground rod next to your electrical service entrance. A sturdy clip would do the trick. I use a pair of jumper cables to make the connection.

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  3. I have the ground wire for my (old) house’s electric panel exposed a small bit in front of our house before it runs under the crawl space to the .

    Can I just connect to this ground if I set my generator up in the front yard?

    Thanks!

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  4. I see on Amazon screw in the ground anchors that they say will work as a ground rod. While I have used them to tie a long leash to for my dog, not sure they will provide the necessary ground capabilities for my generator.

    What do you think.

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  5. I live in N. CA as well. I was able to drive it into the ground using a jack hammer/breaker without a chisel insert. I happened to buy a breaker b/c of backyard work. You can buy one on Amazon, but it it’s for this sole purpose, then maybe borrowing a neighbor’s one may be cost effective?

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  6. I’m confused by the 4ft rod buried 8ft deep. How is that possible? I thought the rod needs to stick out of the ground about 4″ to attach a copper wire to it.

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    • The article states, in part, “The copper grounding rod should be hammered into the ground or buried at least 8 feet deep (although you can buy a 4 foot rod, but 8 is standard for home installations).” The “…8 feet deep…” is referring to using the standard 8 foot long grounding rod (“but 8 is standard”). Note that the reference to the 4 foot rod is in parentheses, thereby indicating that it is an aside comment. The writer is not telling you to bury a 4 foot rod 8 feet deep. He is merely telling you that 4 foot long rods are available. An 8 foot long rod should be buried (driven in) ALMOST 8 feet deep, leaving enough room at the top (maybe 6″) to attach the grounding wire.

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  7. I would like to know if FL law allows hook up of generator with TT-30P (3 wire) to house panel using L14-30P (4 wire) by hot bridging the 120Vs. I don’t need 240V (Generator does not produce one) and I will use the generator interlock mechanism installed by a professional electrician.

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    • I doubt they allow it because everything is illegal until made legal, and I doubt anyone will bother or want to make that legal. I’d just do it anyway but then I know how it all works and since you asked I’ll assume you don’t and therefore are at risk of doing it wrong. Ideally you should just get a 240V gen because it would be legal, easier and they normally have more power anyway. I have two gens, a small 1000W 120V to save gas and less noisy for most of the time power is out, then a 4500W 240V for when power is out but I need AC.

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  8. I have two questions: One; why bother. Two; in what scenario would this ground rod do any good? Actually three; is the risk of the ground rod itself worth the bennies, if any? Meaning you have to hammer said ground rod in which involves a sledge hammer or maybe a jackhammer, or having to dig a big hole as one poster noted. So you’re at risk of injury simply installing it (back, shoulder, wrist, eye), then the risk of tripping on or falling on said rod, or tripping on the wire. You likely won’t be able to get the rod out so now it’s a forever hazard. Plus the risk of getting shocked which I’ll get into. Back to question one; why bother, meaning without a ground in what way could it possibly hurt you? Well, in might help with electrical noise, maybe, but imo its more of a threat. A ground is potentially a path back to neutral, depending on how the gen is wired and all mine have been so you just increased your odds of getting electrocuted.
    Picture a car battery. You have to touch the pos and neg to get shocked. Install it in a car and “ground it”, now you touch the pos and anything metal in the car and you get shocked. Well that doesn’t sound safer now does it? With a gen you’re likely doing the same thing if you ground it, you’re turning everything into half the circuit needed to shock you so now all you need is the other half.
    Back in the day when appliances and power tools had metal bodies there was a risk the hot lead could touch the metal inside the body in rare cases. If the tool was not grounded (2-equal sized prongs) you were at risk if say you then touched ground or were standing in muddy water (same thing). If grounded (3-prong) and the hot wire touches the grounded body of the device it would, depending on how your home is grounded, dump full power into it and instantly pop the fuse or be a better path to ground than you are and you’d feel little or nothing.
    These days many things have 2-prong plugs because no matter what happens inside the device the power can’t reach you. They usually have one prong wider so you can only install one way which is usually pointless but in some cases can decrease your odds of electrocution. Pretty much everything that does have 3-prong plugs are just to make the consumer feel better because it usually can’t get you anyway.
    An off the wall example: If you’re in the tub and someone tosses a hair dryer in, you’re more at risk if the tub/drain is grounded and you have hard water, the safety prong on the plug will do nothing to protect you. So in short, the ground in the tub is the threat. Not that it would hurt you anyway because being electrocuted like that is a movie thing, like how every car in the movies blows up when it crashes or catches fire. Being electrocuted in the tub/shower is also highly dependent on your water quality. When I say electrocuted there I don’t mean killed, I mean you can feel it. So if someone is worried about a ground rod then they should also install a water softener because the harder the water the greater your risk of “feeling it”. You should also be sure your ground rod is conducting to the Earth, which you don’t see mention of, but if not, or poory conducting then it’s useless. I live in the desert so I doubt a rod would work unless it reached the moist soil near the water table, and good luck with that, not that I’d want one. There are many scenarios of getting shocked so I can’t explain them all, but these days, thanks to improved appliances/tools and using breakers, you pretty much have to make an effort to do it.
    As for my mention of “depending on how the gen is wired” (or home) refers to your ground being tied to neutral or not. Imo each has some weak advantage but neither really does much in this era, but remember your gen already has a ground which gets tied to your RV or whatever when you plug them together so that eliminates the need for a rod. My gen is 240V/120V and the neutral, ground and chassis are all tied together. If I somehow made contact with a hot lead, either of the 240 sides or the hot 120 side, and I touched an unpainted metal part of the gen I would get shocked. Same if inside the RV, like touching something hot and any part of the RV that is grounded. Pretty hard to find something hot you can touch but not impossible. Point being that if the gen and RV chassis were isolated from the neutral/ground I would not get shocked when touching said hot wire and whichever chassis ground. This is like the car battery; do I make it so I have to have to touch both batt pos and neg, or do I tie one to the chassis so now I only need one wire and any chassis/ground part to get shocked? With neutral isolated you pretty much have to make an appointment to get shocked…
    The only scenario I can picture where an RV/gen is dangerous is if the RV is wired wrong and it’s chassis is hot, but even then I doubt it would get you unless, once again, you grounded the gen.
    My RV’s electrical ground is isolated from the chassis so it’s not only safe, it’s safer than my house.
    So while I don’t expect most people to understand what I’m saying, just note that a ground is not always a good thing and your gen is no doubt tying your RV’s ground together when you plug it in so why have a rod which is imo an actual danger?

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    • Hi Todd,
      First off, Happy New Year and let’s escape the dumpster fire that 2020 was!
      The analogy of the D.C. battery you used above is flawed when using it to explain grounding or more properly earthing or safety ground. A typical properly wired 110v outlet carries one leg of 110v and a neutral ( return ) leg and a ground. The ground is earthed ground. The neutral returns to the bus bar in the breaker or fuse box. In a home system the neutral should carry no current. Only in an unbalanced polyphase ( 3 phase most typically ) would neutral carry current. NEVER wire the neutral to the ground! This can create your electrical bathtub, fixture etc… The reason you get shocked in the bathtub is that the neutral and hot leg are bridged by you, the water and the neutral. You have effectively become the nichrome heating element of the hair dryer. The tub could be fiberglass or fully insulated you would still be shocked. Now comes the safety aspects of ground and modern ground fault. When the modern hair dryer is plugged in with its 3 prong plug, into the ground fault outlet, when the hair dryer hits the water it senses the current between the hot, neutral and ground and trips off the outlet in milliseconds. Thus you avoid plumping like a ballpark hotdog! In the old 2 wire setup you would have created an unbalanced current and at the point the draw exceeded the rating of the breaker, fuse or nickel under a blown fuse, the current would have shut off ( you’d be cooked ). Now back to the generator earth ground. Should the generator experience a short, in say a mouse eaten wire, field arcing etc… The earth ground will drain it safely away. Most modern portable generators ground through their cage and when setting on the ground provide some measure of safety against hazardous shorting. Now to your RV example. Your RV electrical system has to be separated from the tow vehicle or body load chassis. Most cars and light trucks are 12 volt DC. The engine control computers, oxygen sensors, headlights, ignition etc… Run on 12v. Now say you mixed the grounds using them for both 110 volt AC and 12 volt DC. In the event of a short, the vehicles electrical controls, lights etc would cook. I’ve seen it happen!
      In most cases your generator will ground through the house ground system just fine. Follow manufacturers recommendations and earthen ground your generator if it’s recommended. Now how to do that in the desert southwest. Go buy yourself that 8 foot ground rod and 20 feet of 12 gauge copper ground wire and 4 ground rod clamps and 2, 5 lb. bags of clay based cat litter, nothing fancy. Start dribbling water on an 8 foot long section. If you can’t hose water outside get 4 , 5 gallon plastic buckets and drill a 1/4 inch hole in the bottom of each. Fill them 3 times a day for ~3 days. Cut the grounding rod into 4 equal pieces. Beneath each bucket dig a 1foot 8 inch deep hole approximately 6 inches across. Mix the soil and cat litter together and re fill the hole. About a 3:1 soil/cat litter mixture. Not critical tho. Next tap the 2 foot section of ground rod into the filled clay dirt mixture. Space them 2 foot apart traveling toward your desired ground connection. Repeat 3 more times. Line up the ground clamps with their neighbors and thread through the copper grounding wire and make sure the connections are tight. And finally , connect to your ground terminal. Several years ago in the midst of a five year drought my electric fence to keep our horses in stopped working, because the house and barn grounds had become too dry to operate. Watering them didn’t fix the problem. It was simply too dry. The clay holds water even in dry conditions. You can water them and they will begin to work again and stay working for weeks. I live 25 miles from the grocery store and often get to run my generator to power my home due to ice storms, tornado damage etc… My generator is 40+ years old, all cast iron and impeccably maintained in its shed. I’ve replaced the outlets, brushes, engine over the last 30 years. If your computer matters to you put them on a quality ups power supply. You can also use the ups screen to monitor the voltage and frequency output. Put your appliances on a surge protector also. I sold generators and transfer systems at one point in my life. Though my old generator will automatically start, automatic switchgear can be finicky. I currently have an air gap manual switch that I can pull a lever and manually separate from the power grid. I then start the generator let it stabilize and throw on the 50 amp breaker to circuit the generator to the house. My rural electric co-op was all too happy to install the switch and a 50 amp dryer plug in an enclosed box on the pole. ALWAYS be certain that you are positively disconnected from your power grid before powering your house, backfeeding a power line can create a dangerous and potentially deadly risk to lineman who are trying to restore your power!!

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  9. If your electrical wire already has a ground wire on it, so that you can just plug it in to your generator, and if your generator is sitting on the ground, why should you have to run another wire to a rod to ground the generator?
    this does not make sense as to every time you move the generator you have to move your grounding pole!!
    Something does not seem right with this picture

    Reply

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