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Portable Generator Transfer Switch – The Guide for 2020

So you want to use a portable generator as a home backup power supply in the event of emergencies. This is a very wise precaution measure and will indeed save you a lot of headaches next time the major storm hits causing the widespread power outage.

However, apart from the portable generator, you need one more important accessory to make your backup power system work.

It’s the generator transfer switch.

A transfer switch allows you to connect a portable generator to your home and large all appliances permanently connected to your house grid without having to use any other additional equipment.

It’s also the only foolproof solution following legal building codes and safety measures.

Transfer Switch for Generators

Do you need a transfer switch for a generator?

If you found our page in Google while searching for the answer to the question “How to connect a generator to the house without a transfer switch?” – here is what we have to say about it.

Even though it is technically possible to hook up a portable generator to a house using an extension cord without a transfer switch – we DO NOT recommend doing so at all.

This is for a few major reasons:

Safety precautions

Connecting a portable generator to a house without a transfer switch can be a dangerous affair.

In such case, if you hook up a portable unit via an extension cord and turn it on during the power outage, it will keep running even when the power is restored in the grid.

The power would then go back down the line to the generator resulting in the back feed. This could not only damage the generator (and potentially all the equipment powered by it) but also would in the worst cases cause fire or electrocution.

We are not joking if we say that connecting a generator without a transfer switch could be fatal.

Unless you are a skilled electrician who knows 100% what they’re doing, for your own safety do not attempt to use a portable generator for home without a transfer switch.

The only way to power hardwired appliances

A transfer switch is the only way to run the major appliances connected to your circuit breaker panel.

These include things like built-in dishwashers, cooktops or water heaters.

You can’t run these if you don’t have a transfer switch installed.

What Do You Need to Pay Attention To When Choosing a Transfer Switch

There are a few major factors you need to take into account when buying a transfer switch.

1. Wattage

Make sure you get a transfer switch that can handle the rated wattage of your generator.

Eg. if you have a generator capable of providing up to 7500 running watts, get a transfer switch supporting generators up to 7500 watts.

If you haven’t bought a generator yet and you aren’t sure what size of a generator do you need, check out our calculator to get the rough estimate.

2. What’s in the kit

Most of the reliable manufacturers such as Reliance Corporation sell the transfer switches complete with all accessories needed for their installation. This eliminates the need to purchase any additional parts.
However, it won’t harm to doublecheck if this is indeed the case with the transfer switch you are willing to purchase.

This would save you from any unpleasant surprises or additional costs when the electrician arrives to install it.

3. Type

There are two common types of transfer switches: manual and automatic. Both have their pros and cons.

However, for most of the homeowners, the manual switch would be the most recommended solution. We explain why below.

Manual vs Automatic Transfer Switch – which one is right for you?


  • Cheaper – manual transfer switches cost a fraction of the price of automatic units. If you think that you are only going to use the generator a few times a year – getting a manual switch could be a reasonable cost-effective decision
  • Easy installation – manual switches require significantly less effort to install which makes them even cheaper to buy and set up as you won’t have to spend that much money on the electrician’s time
  • Just like the name suggests, every time there is a power outage, you need to flip the switch manually in order to make the generator run your home. However, flipping the switch is a very easy task and does not require any specific knowledge.


  • If you are looking for a hand-free approach and want your generator to power up your home almost automatically without needing to mess around with the transfer switch – the automatic type is the right way to go.
  • Automatic transfer switches save you the hassle of having to flip the switch every time there is a blackout. All you need to do is simply turn on the generator and you’re good to go.
  • A typical automatic transfer switch is usually more expensive than a manual transfer switch. You need to ask yourself whether you want to pay much more for the transfer switch if you are only expecting a few power outages a year. A good quality automatic transfer switch can cost more than 1,000 dollars which is more than the price of a decent portable generator!

My Verdict

If I were you, I would go for the manual transfer switch. While it might sound like a bit more of the hassle first, it gives you better control over what is powered by a generator and what is not in case of emergency. It’s also a much more cost-effective solution.

What is the best transfer switch for the generator?


If you decide to purchase a manual transfer switch, the ones manufactured by Reliance Controls Corporation come highly recommended.

They are widely regarded as the best switches on the market and are seen very commonly in American households. When you hire an electrician to install a transfer switch made by Reliance Controls there is a high chance that they’re gonna know that exact model extremely well.

For generators up to 7,500 watts – Reliance Controls Corporation 31406CRK 30 Amp 6-circuit Pro/Tran Transfer Switch Kit

This is currently the most popular transfer switch on the market.

The kit contains all accessories needed for the complete installation of the transfer switch. These include the 10 feet long power cord, PB30 outdoor remote power inlet box, wire nuts, and the male plug for 20 amp generator outlets.

It is the ideal solution for generators with a maximum wattage of 7500.

For generators up to 12,500 watts – Reliance Controls Corporation 51410C Pro/Tran 10-Circuit Indoor Transfer Switch

If you are planning to run a larger generator to power nearly the entire household – this is the transfer switch you should use.

It will cooperate well with ultra-duty generators like Duromax XP10000EH or Westinghouse WGen12000.

This unit features a steel cabinet, resettable circuit breakers, 6 combination knockouts,
and double-throw switches.


There are not many automatic transfer switches on sale since they are generally much less popular and way pricier than the manual switches.

Generac is the most recommended brand specializing in manufacturing whole house generators and the dedicated automatic transfer switches.

As of today, their most popular transfer switch is Generac RTSW200A3.

Do I need anything else to connect my generator?

One more accessory which is not always sold together with a transfer switch is a power cord.

It is often included in the kit with most of the generator transfer switches. However, if you realize this is not the case, make sure you purchase the right type of power cord.

For portable generators, it should be a 30 amp cord. You can tell the amperage by the number of male prongs – it should be 4.

Make sure to also take the length of the extension cord into account. If you are planning to place your generator far from the transfer switch, a long extension cord is a must. Bear in my mind that those which are sold together with the generator transfer switches are sometimes quite short.

How to install a manual transfer switch?

We recommend hiring a certified electrician to perform the installation of the transfer switch.

However, if you are confident about your DIY skills, you can check out this comprehensive guide by Electrical Engineering Portal. It explains step by step what you need to do when installing a manual transfer switch at your home.


Do I need a permit to install a transfer switch?

Technically yes, you need a permit from the local authorities whenever you install any permanent additions to your house. Generator transfer switches are no exception.

However, if you hire a certified electrician for the installation, they will usually be able to sort out the permits on your behalf.

How much does it cost to have an electrician install a transfer switch?

The costs of hiring an electrician can vary a lot depending on where you live, your house structure etc. As a rule of thumb, it should take them around 3-4 hours to perform the whole installation of a transfer switch and cost up to $500.

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Reliance Controls - best transfer switches for portable generators

My name's Craig, I am a general contractor currently living in Dallas, TX. I've worked with different kinds of electric tools throughout my career, including the portable generators. In my spare time, I love going camping and tailgating with my family and friends. I've created this site to provide honest advice for people looking for the right portable generator and other related equipment for work and leisure.