Transfer Switch for Generator Power in Outages

Poohbear

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saturday night here demonstrated the value of the auto transfer & permenate generater. That storm was a giant lightning storm & almost no rain and when we lost power there was no way I would have gone outside & hooked up our portable genny. This is the 2nd time this summer we've had this massive lightning. This time however my gen had just started up when power came back. Back in June power was out for about 12 hrs but parts of East Tx were out for a week from all the trees down & poles blown down by straight line winds.
Nothing wrong with portable gens & manual switchs but as above there are times to not be out in the weather setting up. Just something to ponder when makeing home generater plans.
 
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RCW

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What brand of electrical panel do you have? I'm an electrical contractor and have installed many 30amp and 50amp generator inlet boxes with an appropriate "interlock kit" for a portable generator.
Sqd Homeline and Qo for newer panels can be found easily and cheaply online.
Older sqd panels and other brands can be found at interlockkit.com
Use #10 copper for a 30amp inlet box and #6 copper for a 50 amp.
@dclauria - our contractor has recommended an interlock kit like you mentioned too. Says he's done many, both 30 and 50 amp.

Certainly appears to be appropriate for our circumstances.

I have a 200A Square D Homeline panel, and a Sq. D Homeline subpanel in the garage.

Can that subpanel be used to feed the generator breaker with a dedicated generator 50A circuit and breaker in the subpanel, with a twist-lock plug?

Or does it need to be a separate feed to the generator breaker directly to the main panel?

I have #6 copper feeding the subpanel from the main on a 40A breaker. The twist-lock plug would be #6 THHN to the subpanel, if feasible.
 
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wp6529

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@dclauria - our contractor has recommended an interlock kit like you mentioned too. Says he's done many, both 30 and 50 amp.

Certainly appears to be appropriate for our circumstances.

I have a 200A Square D Homeline panel, and a Sq. D Homeline subpanel in the garage.

Can that subpanel be used to feed the generator breaker with a dedicated generator 50A circuit and breaker in the subpanel, with a twist-lock plug?

Or does it need to be a separate feed to the generator breaker directly to the main panel?

I have #6 copper feeding the subpanel from the main on a 40A breaker. The twist-lock plug would be #6 THHN to the subpanel, if feasible.
You have to feed at the main panel if you want to be able to provide generator power to all your various circuits. An interlock kit on the sub panel is legit as far as code and would have some applications , however it would only power the circuits on the subpanel.

As for tending generators in inclement weather, I've stood in my bathrobe at 11pm next to an 80' tower a.k.a. lightning rod, in a torrential severe thunderstorm, refueling a running gas generator :) Nothing scares me.

I do now have a much larger diesel generator with a 100gal tank so I won't be doing much of that tending anymore however I do still use a manual interlock transfer setup.
 
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P0234

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Interlock is the way to go if you have the room to put it in your panel. The generlink idea is cool but the utility companies don’t seem to like them anymore. I can’t get mine to install one at the new place, they say they don’t do them anymore and to get a whole house generator from their partner… no thanks.
 
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RCW

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Guys - - appreciate all the advice.

Think I'm heading in a direction - right or not TBD..... :rolleyes:

I (think) I'm going with an interlock on the main panel as @dclauria and @P0234 recommended.

Genny can't feed the panel lest the Main Breaker is off and Genny Feed Breaker is turned on. Appears legal far as I can tell.

Possibly looking to feed the Main via a subpanel in my garage. It's connected to the Main panel via 6/3 Romex.

IMG_6265.jpeg

No main breaker on the subpanel, as it's an attached garage connected to the house system, ground, etc.

Subpanel was put in for my welder, a future 240v air compressor, and some 120v outlets. (Also thought of generator backfeeding without protection:().

Put a 50A Genny breaker in the subpanel, and another 50A in the Main panel, interlocked with the 200A Main Breaker....

Subpanel is right at my garage overhead door - -where I always run my current generator - - which I run120v extension cords to.

I can put a simple 14-50 plug off the subpanel via #6 THHN right next to my welder plug......

Make sense?

I will resurrect my older Thread about Generators - I think (??) a Floating Neutral Generator makes sense in this application?

If a Genny were Bonded Neutral, 2 bonding locations could actually be a hazard?
 
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trial and error

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The interlock.is code (I think) the floating neutral I'm a little fuzzy on as well.as the rest I'm sure others will chime in.
 

P0234

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Guys - - appreciate all the advice.

Think I'm heading in a direction - right or not TBD..... :rolleyes:

I (think) I'm going with an interlock on the main panel as @dclauria and @P0234 recommended.

Genny can't feed the panel lest the Main Breaker is off and Genny Feed Breaker is turned on. Appears legal far as I can tell.

Possibly looking to feed the Main via a subpanel in my garage. It's connected to the Main panel via 6/3 Romex.


No main breaker on the subpanel, as it's an attached garage connected to the house system, ground, etc.

Subpanel was put in for my welder, a future 240v air compressor, and some 120v outlets. (Also thought of generator backfeeding without protection:().

Put a 50A Genny breaker in the subpanel, and another 50A in the Main panel, interlocked with the 200A Main Breaker....

Subpanel is right at my garage overhead door - -where I always run my current generator - - which I run120v extension cords to.

I can put a simple 14-50 plug off the subpanel via #6 THHN right next to my welder plug......

Make sense?

I will resurrect my older Thread about Generators - I think (??) a Floating Neutral Generator makes sense in this application?

If a Genny were Bonded Neutral, 2 bonding locations could actually be a hazard?
If I'm reading it right, if you use the sub panel to backfeed the main, then the interlock on the main will make the sub panel useless unless the main is off.
 
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Chanceywd

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If I'm reading it right, if you use the sub panel to backfeed the main, then the interlock on the main will make the sub panel useless unless the main is off.
That I believe is how they work when ever you use one. I have one in my main panel I put in before the auto transfer and back up generator.

I think you would have to run a separate feed from the garage back to the main panel to the dedicated breaker. That is always off until the main is turned off to allow it to be turned on. This feed is terminated in the generator end with an inlet which looks like a recessed male plug end. Then you have no danger of those exposed inlet prongs.

Bill
 
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RCW

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If I'm reading it right, if you use the sub panel to backfeed the main, then the interlock on the main will make the sub panel useless unless the main is off.
Duh….my idiot was obviously showing…😜

Thanks to you and Bill, @Chanceywd for making me think this through more thoroughly.

Someone pointed that out earlier and I obviously didn’t get it with the interlock.

Sometimes I’m not very smart. Just ask my wife….😳
 

Chanceywd

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Duh….my idiot was obviously showing…😜

Thanks to you and Bill, @Chanceywd for making me think this through more thoroughly.

Someone pointed that out earlier and I obviously didn’t get it with the interlock.

Sometimes I’m not very smart. Just ask my wife….😳
I have a lot of those days myself, glad to be able to help along with P0234. His post made me see the misunderstanding.
If I haven't explained before here is Chanceywd's explanation. As a dog lover you will appreciate it.
In the late 90's I had a GSP I named Chance who I rescued. Chance because he got a second chance in life and it evolved to Chancey white dog as he was mostly white and my other one was mostly Liver.
Loved my GSP's and they live on in my head using them in my online etc. I have a couple mixed breed guys now that make me smile every day.

This is Rudy in the lead and Libby!

Bill
 

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P0234

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Duh….my idiot was obviously showing…😜

Thanks to you and Bill, @Chanceywd for making me think this through more thoroughly.

Someone pointed that out earlier and I obviously didn’t get it with the interlock.

Sometimes I’m not very smart. Just ask my wife….😳
It happens to all of us. Just run a wire from your main panel to where you want your generator and use an interlock. Or if your utility supports it, a more expensive option but one that works really well is a Generlink. That's the option I would have gone with if my utility supported it, its the most flexible, probably the safest, easiest install and it doesn't eat up two slots in your panel. Bonus if you have multiple panels on one meter, it supports that too.
 
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