How To Wire a Standby Generator

Purchasing, wiring, and installing a generator are wide topics and we get a lot of frequently asked questions about standby generators, so we have decided to answer these questions bit by bit.

Apart from the explanation of how to wire a generator, we have also answered a couple of vital questions. Since we believe that safety should come first in all you do, we also gave some precautionary tips and warnings. So, sit back and read through the article.

Why Do Generators Have 4 Wires?

This is common among 2-phase generators. The 4-wire cord includes two hot wires, a neutral and a grounding wire. The two hot wires are designated for two slots on a double-pole breaker, while the neutral runs to the bar assigned for neutral cords, and the grounding cord runs to the insulated rod.

The neural cable carries imbalance currents running from the power source to avoid electrical trips. At the same time, the grounding wire ensures current flows back to the source as the case may be to prevent the flow of current in the electrical box as breakers keep shortening the current influx intermittently.

So, even if there is going to be bonding between the neutral and grounding wire, it would be at the entrance to the transfer switch only.

Is it Legal to Connect a Generator to Your House?

The answer to this question is yes and no. Yes, it is legal to install a generator and connect it to your house in many areas, and no, it is not allowed in some areas.

However, it is accepted in most areas but with certain regulations and requirements. We have used California for illustration because it is the most strictly regulated state in the US.

Here are some of the requirements for the installation of a standby generator in California.

1. You must seek and get the required permit before you purchase and install any standby generator.

2. The noise level of your generator should not exceed 45dB (decibel).

3. The installation of your generator must comply with the building code of your county.

4. It must also comply with your county’s fire code.

5. The generator must be re-certified every year.

6. If your standby generator is allowed in your county, it does not mean that it will be allowed in another county.

Although the list is long, the requirements listed above are the most important ones. To answer the question, if you’re able to obtain the required permit, it is legal to connect a standby generator to your house, but if you’re not able to obtain the permit or your application is declined, then it is illegal to go ahead and install your generator.

Can You Run A Generator Without a Transfer Switch?

The answer depends on the type of generator you’re using.  First off, let’s explain what a transfer switch does. It prevents the load center from receiving power from the grids and the generator at the same time.

When that happens, your entire electrical circuit could be damaged. Your appliances could get fried. Once a power outage occurs, the transfer switch will sense it and it will send a signal to the generator to start it.

Then it will change the source of power to the load center from the grids to the generator. This happens within a few seconds. If you’re planning to install an automatic generator, you definitely need a transfer switch.

That type of generator does not have a manual start. It starts up automatically upon receiving a signal from the transfer switch. On the other hand, if your generator isn’t automatic, you can connect it without a transfer switch since you’ll be the one to start it manually.

However, you must install an indicator light that will alert you when power is restored. Otherwise, you’ll have to ask your neighbors or monitor their lighting to know when power is restored.

How To Wire a Standby Generator?

Before we explain how to wire a standby generator, we want to warn you not to handle it yourself if you’re not an expert. Electrical installation is no child’s play.

A lot can go wrong. You can damage your generator or your home appliances. Accidental electrocution could occur, and it can also lead to a fire. Violating any of the county or fire protection codes can get you on the wrong side of the law.

Most importantly, the warranty on your standby generator could be voided. Now that we have informed you of the risk involved let’s list the required steps.

Step 1 – Link the transfer switch to the load center. The load center is the box that supplies your entire home with power. By default, it receives power from the grids.

Step 2 – Set up the power inlet box and install it outdoors. It must have a strong power cord that will be plugged into the generator.

Step 3 – Link the transfer switch to the power inlet box. So, one end of the transfer switch is connected to the load center, while the other end is connected to the power inlet box.

Step 4 – You can then connect your generator to the power inlet box with a cable. When the generator starts working, it sends power to the power inlet box.

The inlet box sends the power to the automatic transfer switch and the switch sends it to the load center that powers your entire home.

What Kind of Wire Do You Use for a Generator?

A 60amp breaker would need a 6gauge wire while a 40amp beaker would require an 8gauge wire. 2gauge wires would suit amp breakers up to 100amp. The element used for the construction of the wire would determine its conductivity, which could relatively affect current losses.

The gauge decreases on and on as the size of breaker increases. There are several companies that are specialized in the production of wires. Find out the ones that have conformable measures with the NEC code standards.

How Do You Size a Generator Cable?                        

Check the manual of the generator and read it. Know the overall wattage of the generator. Determine the amperage needed to get your pieces of equipment powered. Check the voltage you’ll also be using; it’s always 120V or 240V. Divide the overall wattage with the circuitry voltage to understand the amperage needed.

For instance, the overall 24kw, then it means the amperage for the entire house is 120Amp. Invariably, a 200amp service is the best for the home. There are single-pole breakers and double-pole breakers. They can be of different sizes based on the amperage of the breaker.

The size of wires connected from the standby generator would be the same to avoid overheating the wires. Notwithstanding, precautionary measures have to be put in place to ensure the fixation of the wires to the generator is done appropriately.

What Size Wire Do I Need For a 100 Amp Generator?

You’ll need #4 AWG copper wires or #2 AWG aluminum wires for 100 Amp service. AWG stands for American Wire Gauge, and the difference in the elements’ sizes is their differences in electrical conduction. Factors that lead to current losses are distance, cross-sectioning, and the size of the wire. Choosing this would ensure that current losses don’t surpass 3%, as recommended by NEC.

Is 10 3 Wire Heavy Enough for a Generator?

Yes, a 10-gauge wire is an appropriate size for a 30amp breaker. The breaker can protect the wire of such a gauge from enhancing maximum effectiveness and prolonging the lifespan of the wire. The code is assumed as 10/3 with the ground

Precautionary Tips

There are two sides to a coin. The generator can be helpful for providing a backup power supply, and it can be dangerous if not properly handled. Here are some important precautionary tips.

1. The generator gives off dangerous fumes like carbon monoxide, so it should be installed outside. Don’t install it in your garage or in any enclosure because the harmful gases will quickly build up.

2. Many parts of the generator become very hot when the generator is in use. So, ensure that your kids and pets do not go near the generator whenever it’s working.

3. Don’t let your generator run out of fuel while in use. It will suck in the dirt and debris in its tank, thereby shortening its lifespan.

4. Also, don’t fuel the generator while in use. A fire could be ignited that way. Remember, all its components will be hot by then. Before you fuel it, turn it off and allow it to cool.

5. After turning your generator on, turn on your appliances one at a time to prevent overloading. The higher the load on your generator, the more it will drain your fuel. So, use it to power only the appliances that you really need.

6. To avoid back feed, don’t plug your generator in the wall.

7. Keep moisture away from your generator as much as possible to prevent accidental electric shock and short circuits.

8. Follow all manufacturer’s instructions.

9. Hire only qualified technicians to work on your generator.

Signs of Carbon Monoxide Inhalation

One dangerous challenge with the use of generators is the unconscious inhalation of carbon monoxide given off by the generator.

Once you or someone in your household begins to experience some of the signs below, carbon monoxide may have already started building up in your home.

  • Constant headaches, especially when it occurs only when the generator is on.
  • Another common sign of carbon monoxide poisoning is nausea.
  • Breathing with difficulty.
  • Dizziness or loss of consciousness.
  • When someone suddenly slumps.

When you notice any of these signs, you should investigate your home for the presence of carbon monoxide. In addition, the affected people should be taken to the hospital.

Final Word

It is a good idea to know how to wire and install a generator, but you should never try it if it’s not your field. You lack the experience, expertise, and tools needed for the installation. You may also have problems with the codes.