Replace service disconnect with a mythical three way switch
In light of the recent 5 degree (F) temperatures in the south, and in light of losing power, with two kids under two, It’s been suggested (many, many times) that we get a portable generator in case the power ever goes out again. Initially I was hesitant, but I started a few back of the envelope calculations, and it’s less costly to get a 8 kW generator that will power the whole house, than to replace about two busted pipes, depending on their location. So here we are, with a new portable generator, and myself considering all of the options on the ways I could wire it in to the main panel.
To give you peace of mind, right beside me (virtually) is a copy of the local codes, and the latest IRC and NEC. I’m not looking for a hack job, rather, wondering if a certain product exists.
What I think would be easiest, is to replace the main breaker, which is mounted on an external wall, with a large switch that has three options. Service Feed, Generator Feed, and Disconnect. A big lockable lever that is easy to rotate into any of the three positions, but can never be in more than one position at any time. The service feeding in from the bottom, and a generator inlet from the side.
I feel like that’s something that ought to exist on the first google search, but maybe I’m still sleepy from the holidays. Is there a name for such a device, if it exists? I have seen the automatic transfer switches, but I’m not really in that market. Just a easy, reliable switch that could be put in that place would seem to make the most sense from where I would want to position the generator, and require the least amount of modification to the rest of the system.
Thanks!
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Go to your breaker panel, find the model and then start looking for an "interlock kit".
It is a relatively simple stamped sheet metal part that gets installed in your breaker panel. You install an additional appropriately sized breaker in the top position of the panel that will be for your generator to feed in. You should also get an outlet installed specifically to plug the generator into.
You can find videos that show how it works, but the interlock kit makes it so that in order for your main breaker to be in the on position, the generator breaker has to be in the off position and vice versa. This is the equivalent of your switch, but its actually easier to install. It is the simplest way to safely connect a generator directly to your breaker panel.
If your generator is permanently installed and turns on automatically, then it starts to make sense to add an automatic transfer switch into the mix.
Deleted
Can't help you with a 3 way switch, but my electrician installed a fool proof option. Where the main breaker is located, he installed a steel slider that when open, the breaker switch is open and feeds power from the grid. When closed, it the breaker switch moves down and supplies power from a generator plug on the outside of the house. In either position you cannot move the breaker to the other supply position. Easy.
The only drawback is I have no idea when the power outage has been fixed. I keep an eye on the neighbors and listen for no generators running.
Thanks guys! I have seen those, and I may default to that option if nothing else pops up. I was hoping to keep everything external, so that I wouldn't have to touch the panel at all, if that makes sense. One 30A breaker right beside the generator inlet box would keep everything happy, it seems. I'll keep looking and report back if I manage to find anything cool!
Why don't you want to touch the main panel if you're okay touching what you call the "main breaker" (by which I think you mean service disconnect)?
You’re right, service disconnect. I’m being sloppy!
I’m not opposed to it at all, I just thought it would be nice to have the feed into the panel be agnostic to the power source, and save on a bunch of cable, which ain’t cheap right now.
Also because the service disconnect is right beside my porch, where I would likely set the generator. It would be a 10 ft cable run from the generator to the replacement, and everything’s all hunky dory, just go throw the switch.
> Also because the service disconnect is right beside my porch, where I would likely set the generator. It would be a 10 ft cable run from the generator to the replacement, and everything’s all hunky dory, just go throw the switch.
Ah okay, that makes a lot of sense.
You could consider searching for service rated transfer switches. Here's one I found: https://www.electricgeneratorsdirect.com/Reliance-Controls-TWB2005DR/p1125.html
It would replace your service disconnect. If you ever would consider a fully automatic generator in the future, you could also consider an automatic transfer switch from the manufacturer you're likely to install, and operate it manually in the mean time.
Sound like you are looking for a “Interlock Kit” The kits are made to fit many makes and models of panels. They allow you to power the generator thru a breaker that can only connect to the panel when the main breaker is in the off position.
Some local authorities get very particular about interlocks so check with them before you buy any hardware.
The interlock is 1/3 of the required equipment. You also need a special socket install on the outside of your home and the matching cord.
https://www.amazon.com/GenSafety-Generator-Breaker-Panel-Interlock/dp/B09RGP1QR3/ref=asc_df_B09RGP1QR3/?tag=hyprod-20&linkCode=df0&hvadid=563702687488&hvpos=&hvnetw=g&hvrand=10210808239704772244&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9022908&hvtargid=pla-1642387760306&psc=1
https://www.amazon.com/dp/B09JFV55FQ/ref=sspa_dk_detail_5?psc=1&pd_rd_i=B09JFV55FQ&pd_rd_w=7YNib&content-id=amzn1.sym.dd2c6db7-6626-466d-bf04-9570e69a7df0&pf_rd_p=dd2c6db7-6626-466d-bf04-9570e69a7df0&pf_rd_r=RE85RD9ZM3QWCRSVTWJP&pd_rd_wg=qatld&pd_rd_r=c014e441-c026-4e77-bfce-6afed3c16491&s=hi&sp_csd=d2lkZ2V0TmFtZT1zcF9kZXRhaWxfdGhlbWF0aWM&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUEzTTNaQk5KVkVKUFY5JmVuY3J5cHRlZElkPUEwOTcxODUyQUZQVzRNQjY2Mkk0JmVuY3J5cHRlZEFkSWQ9QTA3NTI4NTEzOTZFQUtTRVJUUjVQJndpZGdldE5hbWU9c3BfZGV0YWlsX3RoZW1hdGljJmFjdGlvbj1jbGlja1JlZGlyZWN0JmRvTm90TG9nQ2xpY2s9dHJ1ZQ==
Walta
I believe I found what I'm after, though the price has me wondering if it's plated in gold on the inside! A double throw safety switch, similar to this one.
https://www.se.com/us/en/product/DTU324NRB/safety-switch-double-throw-non-fusible-200a-240-vac-250-vdc-3-poles-15-hp-neutral-nema-3r-bolt-on/?filter=business-4-low-voltage-products-and-systems&node=12144220094-double-throw-safety-switches&parent-subcategory-id=80379&range=7271-double-throw-safety-switches-&selected-node-id=12144220094
Just FYI. Trying to source a similar item that's not $3K.
Does something like this not do it?
https://www.amazon.com/Reliance-Controls-Corporation-CSR202-Generators/dp/B00AHTWNH2/ref=dp_fod_1
Very close! I'd need 240V and greater than 5 kW but otherwise that's exactly what I'm looking for.
I think what you are looking for a manual transfer switch:
https://www.generac.com/generaccorporate/media/library/content/all-products/transfer-switches/portable-transfer-switches/single-load-mts-spec-sheet-10000037566.pdf?ext=.pdf
That looks like it only feeds a 100A main, is that right or am I interpreting it incorrectly? Something like that is what I’m after, with hopes that it would match the service feed, 240V 200A.
2nd for the interlock kit. Super cheap and it's the safe way to do it.
I think I’m narrowing in on it.
https://www.generac.com/all-products/transfer-switches/manual-transfer-switches/whole-house-200a-utility-30a
It’s effectively just an exterior 3R sun panel with a lockout like others have mentioned.
What you want is either a manual or automatic transfer switch. You would normally need what is known as a "service rated" transfer switch, which basically means it integrates a main breaker, but since you already have a main breaker outside, you could use that ahead of a "regular" transfer switch to save some money. A transfer switch serves to serve a load (your home) from one of two possible sources. These two sources are normally called the "normal" (utility) and "emergency" (generator) source.
I would recommend you use an automatic transfer switch (ATS), for several reasons. The big reason is that if you ever decide to add a permanently installed generator, the ATS will already be in place, simplifying your installation. An ATS will also automatically return to the utility source when it is restored, so you don't have to keep checking if the utility power has been restored. Lastly, some portable generators have the ability to be remotely started, which can usually be connected to an ATS so that they will automatically shut down when the utility power is restored.
Note that many residential ATSes (and probably the Generac one someone linked to) only work with generators from the same company, since the "brain" of the ATS is actually in the generator. These type of ATSes won't work with your portable genset. I would install an Asco ATS in their 260 series, which will work with any generator that uses the industry standard 2 wire start system. Expect to pay around $2,500-3,000 for one of these units. If you aren't familiar with working on electrical systems, I strongly recommend you hire an electrician to install this for you -- it is more complex than installing a light switch or branch circuit receptacle, and the potential for big problems is much higher if you make a mistake on the 200 amp service.
Connect a generator "inlet" to the ATS for the generator to provide power, and use a "generator cord" between the ATS and the inlet. Reliance controls makes a nice inlet assembly, and the generator cord is typically 10/4 SO cable (10 gauge, 4 conductors) with L14-30 twistlock connectors.
BTW, I highly recommend you install a small whole home TVSS (surge protector) on your main panel when you install the ATS. The TVSS device will protect you from power problems, but also from switching transients when the ATS switches between sources. I like the little units from Ditek for this purpose, which are only aroun $50 or so.
One last thing -- interlock kits won't work on the exterior main breakers. Interlock kits only work on panels that have an integrated main and and branch circuit location that can be used as a generator input. An interlock kit won't really work in your application.
Bill
I was waiting on you to join in Bill, that’s all good advice!
I’ll check out that Asco and see what they’ve got. I was hoping to keep this sub $1k, but perhaps I’m just being my old cheap self.
I’ve got a whole home surge
Protector waiting to be put in, going to hit it all at once once we’re a bit warmer.
If you are contemplating an ATS, take a look at the Generlink Meter mounted unit. It is a pretty nifty idea, just make sure your local utility and AHJ allows it.
Now that is cool! I’d never come across those before.
I have a Reliance Controls Panel Link 60A (TCA0606D) manual transfer switch in our race trailer and it's been fine for a year. It's just a pair of interlocked breakers. They might be a little less expensive than other options (though it's crazy how much they get for a pair of breakers):
http://www.reliancecontrols.com/panel-link.aspx?pl=pl&c=&f=
The one I have is indoor rated, but they do have outdoor as well. The chart above lets you sort on that (and other stats).
Well, the basic version of this is run new circuits for critical loads, and don't touch what you have.
If you do the transfer switch, set up a single light bulb on the utility side, so you can see when power comes back up.
Generlink meter base insert is commonly used here in Ontario for this purpose, then manage your internal loads to match the capacity of your generator. Think of it as your transfer switch, grid isolation and external wiring plug all in one very quick to install component.
http://www.generlink.com/
I don't have experience with them personally but have seriously considered installing one. My end goal is an EV with V2H support and a smart panel (span.io) - but that's all a bit of a pipe dream still....
Thanks for the heads up owen, I hadn't come across those, until someone pointed out a similar product earlier. It's def something I would start with if I had to do everything from scratch. That's very clean.
There are some relatively new rules in the code that required either an excessively large generator (which means poor fuel efficiency, so not very green), or load management to shed loads to protect the generator from overload. I put this into the "dumb code" category, because it causes a lot of generators to be way oversized, but it is in there. Generators with combustion engines tend to be most efficient around the 80-100% capacity range. If you run an average load of 25% or less, you're using about double the fuel per kwh you get out of the generator compared to what you'd use at a higher load as a percentage of average capacity of the genset.
Load management is a Good Thing, but complicates what would otherwise be a fairly simple system.
Bill