How To Choose Between A Transfer Switch Vs Interlock Kit With Power Inlet Box

In this video I talk about the transfer switch vs interlock kit with power inlet box when deciding which one is best to hookup your generator to your house. This is probably the most common question I hear when folks are trying to decide the best option for them.

Items In The Video:

Popular interlock Switch Kits. Make sure the interlock switch will fit your panel before purchasing. These are not necessarily the exact same one in the video:

Thank you for watching and for subscribing. You can support the channel at no cost to you by using one of the above affiliate links. This helps support the channel for new content!

Blessings,
Adam

How To Home assumes no liability for damage or injury. How To Home highly recommends using proper safety procedures and professionals when needed. Our content is for entertainment purposes only. No information contained in this video shall create any express or implied warranty or guarantee of any particular result. Any injury, damage or loss that may result from improper use of these tools, equipment, or the information contained in this video is the sole responsibility of the user and not How To Home. How To Home will not be held liable for any negligent or accidental damage or injury resulting from equipment, tools, electrical, fire, electronics or any items contained in this video. Attempt projects and repairs at your own risk.

[grampsradio]

I decided to purchase an emergency power generator after receiving two emails from my electric company, warning me that I live in "what they consider to be", a high risk area, for "public safety power shut-off's" in the event of extreme temperatures and dry conditions. They said that if they deem the chance of wild fires to be high, they may choose to do a "Public Safety Power Shut-off" and that these power shut-offs may last anywhere from several hours to several days!

I chose the Westinghouse 12, 500 starting watts and 9, 500 running watts, dual fuel, 30/50 AMP generator and I purchased two 40 pound propane tanks that hold 9.2 gallons of propane in each tank, along with a pigtail auto switchover propane regulator and a 50 foot, 50 amp power cord attaching to a 50 amp power inlet box and an interlock device. Based on the wattage I predict I'll be using, I expect to use 1/2 gallon of propane per hour, so with 18.4 gallons of stored propane, I should have enough fuel to last approximately 36 hours. When the first tank runs dry at approximately 18 hours, the auto switch-over will automatically switch to the second tank and I'll just un-hook the first tank and take it to my propane refill place to refill it, bring it home and hook it back up.

A Certified Electrician charged $800.00 to install the power inlet box, circuit breaker and interlock device, including parts and the permit and that costs $64.00 at my local County Court House. The permit fee was also to cover the cost of a County approved Licensed, Certified Electrician to come out and inspect, approve and sign off on the installation, which never happened.

I would have "much preferred" a Generac whole home system (24, 000 watts) but the cost with installation and paying the gas company, $3, 500.00 to bring a gas line and meter onto my property, would have totaled somewhere between $13, 000 to $15, 000.00 as opposed to the approximately $2, 300.00 that I spent, in total. I also purchased a couple of portable emergency air conditioners at Loews and that cost approximately $600.00.

UPDATE: Just a couple months after installing the backup power generator, PGE did do a "Public Safety Power shut off". We were on our generator backup power for 25 hours. The backup power generator performed flawlessly the entire time! Money well spent! We now have peace of mind.

[Doug-gpqw]

Generally I think an interlock switch would work best for most people no matter the size of your generator. It allows you to easily change the loads and the size of generator. Clear instructions on its use should be posted in or near the panel.

Lets say you were making dinner on your electric stove when the power went out, and you have a smaller generator. You can turn on the breakers for the range and kitchen lights. After the meal you can turn of the range and turn on the hot water heater and dishwasher. In the winter you would want the furnace on, in the summer the AC, or fans. If you're working in the garage you can turn those circuits on. With a transfer switch you are stuck with what you decided when you installed it.

[philpom]

Interlock kit all day long. Just label your critical breakers in the panel to have on during an outage. Exact same as a transfer switch except the added benefit of being able to energize any other breaker as you see fit. Personally I prefer the flexibility of running anything in the house. A transfer switch removes any flexibility you have and forces a compromise. I have an 11, 000 watt dual fuel on a 50 amp inlet but I could also use my 3300 watt on the same inlet with reduced breakers live at once. I appreciate the video, thanks!

[ApoJake]

Interlock. 100%. You have complete control of what circuits you want to have power to in your entire house. Not to mention it is so much cheaper (and easier) to install.

[Graybeard_]

For me the transfer switch is too limiting. No amount of thinking ahead of what you will need when you install the sub panel can tell you what your needs are five years later. Also, every power outage is different. If it is four+ days long, I want complete control over every breaker. With interlock, while I'm at the panel switching the panel over to my generator, I switch off all breakers except what I need in the first hour. Then as my needs change throughout the power outage, I can switch breakers off and others on. Examples are washer and dryers, fridge and pump. None of these need to have their breakers on all the time. Interlock gives me complete flexibility now and five years from now, short outage and long outage. And it provides me the opportunity each time to turn everything off that isn't currently needed, thereby keeping all unnecessary load off my generator.

[sebastiannielsen]

Also I want to mention it DO exist transfer switches that don't hook into a subpanel, but into the main panel instead, which only consist of a tranfer switch and give same flexibility as an interlock. There are lots of transfer switches, even transfer switches that can automatically measure load current, and automatically start up generators and transfer over the power to backup when grid disappears, and transfer back & shut down generators when grid comes back. Some of these transfer switches will also have a in-line UPS too, so you have completely 100% uninterrupted power.

[genew.]

Bravo!! Finally a video that was helpfull and understandable at the same time.
I have watched several how to do videos on transfer switches. This is the first one that
was clear and to the point. Thank you!!!

[tracynation]

Super. Somebody is missing the ball by not making main breakers with extra generator terminals and wire control so that you can just hit a switch in your house and the main kicks off, connecting the generator. Yes, auto-transfer switches, but i'm talking inexpensive retrofit, not complete replacement. (Remote starting is possible with any generator that has a starter motor, so you would not have to go outside at all.) You can shut off almost anything inside that is not needed without killing the breaker. 💙 T.E.N.

[AFpaleoCon]

For me, interlock is way better, I don't want to worry about individual circuits. That defeats the purpose of a whole home solution....

[jayhebert]

great summary.
Would love a similar video for a battery backup system.

[jimmyraythomason]

I use a transfer switch with my Champion 7500 watt generator to power almost my entire house. I don't have my stove/range, heat pump or cloths dried powered by it because of the high amp draw. I have back up window a/c units for summer use if the power is out during hot weather that the generator handles quite easily. Even though it isolates the generator from the line I always throw the main breaker to guarantee no back feed of the power lines.

[RogerKey-he]

I bought a whole-house stationary generator (24kw) with an automatic transfer switch. I spent a lot of money and wished I had bought a large portable unit with an interlock. What they don’t tell you is that the mfg greatly limits your ability to maintain, repair or even change many of the settings. That puts you at the mercy of local dealers. They have proven to be very expensive and unreliable. My Generac unit had a major malfunction 4 months (5 hrs of total run time) ago and is still out of service. I have called 3 of the authorized dealers and it remains broken. If I had spent only 20% of what I did ($16k), I could have the flexibility to just replace things as they became unserviceable. The dream of no interruption to life when you lose power remains just a dream for me. I wouldn’t do it again.

[rstephe]

Good explanation. I hooked up an interlock with a line coming from an external 50A plug and a 12, 500 watt on propane. I can choose the circuits I want to run and during hurricane season in FL, life with the wife without A/C is hell. I do have a small generator I loan out to others or I can use during cooler months in my house if needed. Costs - the most expensive cost was the cable from the external plug to my circuit panel at $105 and the plug at $43, which you would have to buy anyway. Other costs were the interlock switch for $38, and a 50Amp circuit breaker for $8.

[roushwin]

Nice Video. I went with the 6 breaker Transfer switch powered by a remote start 4500 Watt inverter. Also plumbed it for Natural Gas as well as reg gas. Wanted to stay small so it wouldn't us too much fuel and inverter good for electronics and the RPMs drop when low load. This way I can run the basics, refrigerator, Furnace, lights, internet/ computers TV, Oven (gas oven but needs 110V to open gas valve).

[garrettg]

It seems like the transfer switch is ideal if you plan to switch to generator power often, or if the person doing the switching doesn't understand the loads within the house.

I think the interlock switch would be what I'd personally use, as its nice to have the flexibility to switch what is powered in case you need to use something you didn't plan on when you installed the transfer switch. Although, I'd probably write up a "interlock guide" that shows what breakers to disable for normal 'generator'/backup use.

[sauceswoodworkinganddiy]

For me, the big deciding factor was that my breaker box, while it had some breakers in it (sewer pump, dryer, and a few more), it has 3 large (100A) breakers for "Upstairs", "Downstairs" and "Garage" which lead to three subpanels. If I wanted to be able to switch individual things from upstairs or downstairs, I'd have to rewire them all the way back to the main panel, otherwise I'm going to use large breakers on a transfer switch and still have to go and turn on and off individual circuits not to overload the generator.

The interlock kit was much more straight forward.

[kaitym]

Thank you for your concise explanation of the differences in the two approaches. We recently purchased a largish generator, 10k watt output, and have been looking into our options. Our power consumption calculation is about 8000w, so we purchased something that would not have to run at peak all the time. This allows for home heating with our pellet stove, cold food storage in two fridge/freezers, hot and cold water and lighting. Also figure we can switch off a few things and fire up a computer/TV for some DVD watching while we are "in the dark". We really have appreciated the effort that folks have put into providing clear information about our available choices. Your video and information are top notch! May 2022 bring us all peace and prosperity.

[fattyfat-fat]

❔💥QUESTION💥...Going to build total off-grid, solar & gen. Small house and woodworking shop. 48v rack bats & 24k propane gen-set. Want to run my shop machines on gen separate from bats, and house on solar & bats, use gen for house backup in emergencies. What do i need to have to use the gen backup for house, AND have switching ability to run shop separately on gen? It would be like being on-grid, only my gen would be the grid!! Hope U can help.
-⚡⚡⚡

[sharpenrightservicesllc]

Very helpful. Now I finally know what I'm going to do to connect my gen to my house.

[mcrider]

I like your content.

I find it fascinating that anytime the subject of a backup home generator comes up it immediately defaults to dire warnings that you must use either a transfer switch or an interlock system. If you don't you are breaking all kind of laws and could kill your neighbors or linesmen.

Let's get real for a sec. The interlock system wasn't even invented until around 2005. Transfer switches a few years before. For those of us who live in places like Florida where power outages are a way of life we have been using generator backups long before these two items were even invented.

The whole issue centers around one simple thing. Shutting off your main breaker to the power company. Once it's off it will not come back on until you MANUALLY switch it back on. That's the whole thing in a nutshell. If you are going to use a backup generator for an emergency power outage shut off your main breaker first.

So all the Internet hysteria and dire warnings about killing people, doing illegal things, and breaking the law is just that, Internet induced hysteria.

If you are not capable of understanding that simple instruction then perhaps you should rethink a lot of other things in your life first before worrying about a power outage.


Btw, I ran a 2400 sq foot home for two weeks at full power during a power outage using a suicide cord that I made and plugging it into the dryer outlet. No one died and no one got arrested for breaking the law. It's called an emergency power outage. During emergencies you do what you have to do to get by.

As I said I like your content keep it up. Thank you.