How to Easily Wire a Transfer Switch to Your Home

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No one likes it when there is a power blackout. Good enough, we can take certain steps to deal with a power outage long before it happens. One way of doing this is to install a transfer switch to your home. Once you do this, you will be able to switch incoming power right from the main power panel to your portable generator during a blackout. And you will do this easily and safely.

A transfer switch usually comes in two main configurations. One is manual and the other automatic. Both have their advantages and disadvantages. The moment you purchase the switch, you can consult a professional electrician to help you install it.

Otherwise you can decide to do so yourself following a simple process. We will now walk you through the steps of wiring a transfer switch to the home. You will find the steps simple and easy.  Regardless, let us first talk about some important items required for this project.

The Key Parts

Generally, in order to successfully install a transfer switch to your home, you will need three main items: A portable generator, the transfer switch itself and a power inlet box. If you wish to know how to choose the best portable generator, transfer switch and power cord, just read our guides. You will find three articles containing in-depth information on how to do this.

You need to install your transfer switch properly. You require certain parts in order to do this. You may decide to purchase a comprehensive kit. This usually contains everything that you are likely to use.

  1. Portable Generator

For a start, you need a good size portable generator. As noted, read about the best portable generators for this kind of job.

  1. Transfer Switch

You can use either an automatic or manual transfer switch. You have a wide range of selection available for this. Just take your pick.

  1. Power Inlet Box

The power inlet box is important for the job. It is usually mounted on the outside of the house, specifically on the indoor transfer switch wall. The power inlet box enables you to plug in the power cord easily before it connects to the generator.

  1. Power cord

A power cord will help you connect the generator to your transfer switch. It is recommended that you use a standard 20 foot cord. This is useful since it is long enough to complete the connection appropriately.

Installation Process

If not done well, it can be a daunting job just to wire a transfer switch to the home. However, you just need some little knowledge of the electrical processes to circumvent this. Moreover, with some reasonable attention to detail, you can complete the job in a matter of hours.

In case you are not really at home dealing with the main electrical installations, you are wisely advised to seek the help of a professional technician.

Do remember to comply with local and state regulations that touch on home electrical components. In order to do this, it is important to review these laws, the codes and other general requirements. Once you do this, you will be ready to install the necessary equipment without breaching legal regulations.

Requirements and Ratings

In the US, the standard, split single phase, household electrical service is factored at 120/140 volts. It has black and red ‘hot’ wires as well as white grounded neutral. Between each line and neutral is 120 VAC as nominal voltage. The voltage between two lines is 240 VAC. notably, both lines belong to a single phase. You obtain this by grounding the utility transformer center tap.

A generator transfer switch that is suitable for such a system is supposed to be a DPDT ‘break before make’ type. The term Double throw refers to the capacity of the gadget to be placed or thrown into two positions. Double Pole(DP) indicates that it can transfer two poles or line wires. The neutral doesn’t usually have to be switched because it is continuous. This is unless the generator that you use is fitted with a GFCI, with the neutral wire fixed to chassis.

True Power

The term ‘break before make’ means it actually disengages load from a source prior to connecting it to some other load. If you use the traditional 2-wire 120 volt systems for residential, then you will need a double throw switch for single pole. Install the TS indoors, some 2 feet from the main service panel. Make sure it is done 30 feet within the inlet box. The inlet box should be placed indoors.

Remember that ‘true’ or standard power transfer switches usually have three positions: OFF, LINE and GEN. They pass through OFF position whenever switching between GEN and LINE. This prevents short circuits in the transition. You can install an extra sub-panel or distribution panel for essential power back-up lines if the genset power rating cannot feed the house entirely. The sub-panel is eventually linked to the transfer system. Note that commercially sold TS‘s generally come with pre-wired sub-panel.

Installation Steps

It is good to install a manual transfer switch near the main panel. This helps override normal electric system, using backup generator, during a power outage. You need an operator who will change power to source. Automatic switches help to detect loss of power, start the generator and switch back to backup power feed. Select some few designated circuits in order to receive backup current.

Before buying a backup generator, decide which loads you will want to power. Mostly, what needs to be powered are just a few lights, and the refrigerator or freezer. Avoid starting all circuits simultaneously. It can result in generator overload.

Step #1

Turn off the power breaker in the electrical panel.

Caveat: The terminals will remain energized.

Step #2

Decide the household circuits to be powered. As noted, this might be freezers, refrigerators, the furnace and a few lights.

Step #3

Match the critical circuits with circuit inlet .Balance the load in transfer switch: Remove the knockout found in the service panel.

Step #5

Connect the transfer switch wires into the knockout hole. Be careful not to damage the insulation.  Remember that the label in each wire indicates the circuit in the switch box that it feeds.

Step #6

Fix the conduit originating from the switch box to the main panel. You may use a bushing and locknut if necessary.

Step #7

Fix the transfer switch to the wall. Make sure the nearest edge is at least 18 inches away from the service panel. You can use connectors to do this.

Step #8

Take away the circuit breaker from panel box. Disengage the hot wire lead from the breaker.

Step #9

Connect the red wire to the breaker. This is the breaker that was removed. Reinstall it.

Step #10

Twist the black wire with the old feed wire. The black wire should be from the identical transfer switch circuit.  At the end of it, tuck the wires out at box edge. Go to next circuit. Repeat this process.

Step #11

Connect the red leads to the double-pole breaker.  This is assuming any of the critical circuits are 240 v. If you are not using 240-volt circuits, use the circuits a-piece after removing the handle.

Step #12

Fix the neutral white wire from transfer switch to the neutral bus bar. This is the bar found on the service panel.

Step #13

Attach the green wire from transfer switch to the open port. This is found on the grounding bar. The bar is actually located on the service panel. The transfer switch is now installed! Put back the cover on the panel box. Ensure you complete the circuit map located on the transfer switch.

Conclusion

It is our hope that you have received useful information coming through this guide. This should help you make an informed decision about the most appropriate transfer switch to use in your home. We also hope that you have learnt something about the correct installation process for a transfer switch at home. Whether you decide to learn the simple steps on your own or opt to hire professionals to assist, the important thing is to have the gadget successfully installed in your home.

By and large, a transfer switch should be a great investment that you get ready in advance in order to help restore electricity at home in case of unpredictable power blackouts. At such times, you need to keep important appliances running and this is where a transfer switch really comes in handy.

Share Experiences

Have you ever used a transfer switch at home? How did you benefit from using it, and what unexpected challenges came up? We certainly would love to hear more from our readers about their experiences with the transfer switch.

Of course, if there are any challenges encountered, this would be the right forum to share with other users of generators and similar appliances. Feel free to share with our readers in the comment section below.

Alexey P. , Qualified Electrician and Website Founder

Alexey P. , Qualified Electrician and Website Founder

My name is Alexey P. I was born in Poland but later moved to the USA in 1998. As a well-qualified and fairly experienced electrician, I love working with generators. After my family, the generator could easily be my next love in life! No wonder, I am constantly working with this widely used and very fascinating machine. As a result of my professional training in the field of electrical engineering, I am well versed with the key elements of the trade. I am generally knowledgeable with all inspecting codes and important regulations governing electrical components and repair. I presently live in Monticello, Minnesota, USA. Want to know a little about my life outside work? It is no wonder. If you encounter any challenges with your portable generator while on that camping expedition, you can count on me to help deal with that decisively. I love life. I love people. And yes, I love generators, of course!

One Response

  1. Avatar Steve Clark October 7, 2019

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