Connecting 2-200 amp panels

[Stinson]

Back feeding from a shop to the house.
The house has 2 separate 200 amp panels, unfortunately I need both panels lit up to keep the essentials going.
Thinking about tying the 2 panels together with a breaker?

Cheers

 

[robertsears1]

That’s what I did. Be careful and make absolutely sure you are off the grid the whole time the genset is energized.

Robert

 

[Scoobyshep]

you need to have an interlock to isolate you from utility. Will need more information as to how your panels are laid out. There are specific codes for backfeed breakers.

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[Guyfang]

Highly reccomend you read Scoobyshep post several times. Burning your house and shop down will ruin your whole day. Killing a lineman trying to restore power someplace might not be such a good idea also.

 

[Stinson]

The problem I’m having with the interlock is back feeding from a shop. The shop breaker at the house needs to be left on at all times.
I understand no interlock is frowned upon.
We ran this way at our last place for 20 years. Lost power often, 9 days was the longest.
Always took some time to think it through before starting the generator.

We have a covered area attached to the shop here, would make a good spot for the generator. Wouldn’t hear it from the house either.

I’m open to better ways to back feed to the house.
I appreciate the knowledge base here!

Cheers

 

[Stinson]

The 2 panels in the house are wired separately from the meter.
They were not wired with using a generator in mind.

Edit: At least I think they are. The meter is mounted on the house wall, 2-3 feet behind the meter are the 2 panels. Each with a 200 amp main.

 

[Scoobyshep]

The right way is to run a feed from the generator to your main disconnect.

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[Stinson]

The right way is to run a feed from the generator to your main disconnect.

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I agree, I didn’t think about that.
I have direct bury from the house to the shop that rated around 70 amps.
This summer I plan on installing conduit and upsizing the wire to feed the shop adequately.
It would be easy to throw in another run for the generator.

Thinking I could feed the first panel with an interlock. Another breaker to get out of the first panel and a breaker with an interlock into the second panel.
If that works the only tricky part is the breaker in the first box feeding the second box. Cant seam to wrap my head around what happens when this breaker is left on with utility power feeding the house.

Just about to the point of the wife being comfortable to fire up the generator if I’m not around.

Cheers

 

[Scoobyshep]

Interlock goes on the main

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[nextalcupfan]

Its a bit pricey, but if each of your panels is wired individually to your main I'd put a Transfer Switch in between the disconnect and each panel.
Then just run 2 sets of wires (one set to each transfer switch) from the generator.

 

[Stinson]

Yes, the wire would get expensive. It’s about 150’ to the generator.
The only disconnects are in the 2-200 amp panels.

cheers

 

[nextalcupfan]

Yes, the wire would get expensive. It’s about 150’ to the generator.
The only disconnects are in the 2-200 amp panels.

cheers

By disconnect I mean your electrical meter where the power comes into your house. I doubt that's "in" your breaker panel.

 

[Daybreak]

Howdy,
You are very limited with what you can do. The absolute best would be a transfer switch between the meter and your panels.
Here are some other methods.
Generator connection choices | SteelSoldiers

 

[DieselAddict]

Another option is to do a KIRK key interlock system between the main breaker and the generator breaker.

The lock on the main breaker is key retaining so when its turned on the generator breaker is locked open by the same key. You would have to open the main breaker to remove the key. Take the key to the generator breaker to close it.

 

[Stinson]

Howdy,
You are very limited with what you can do. The absolute best would be a transfer switch between the meter and your panels.
Here are some other methods.
Generator connection choices | SteelSoldiers

Yes, I could see how cutting a switch in between the meter and panels would be the ticket!
It would involve the utility company to pull the meter to disconnect power to the panels.
Doable for sure.

Cheers

 

[Stinson]

Another option is to do a KIRK key interlock system between the main breaker and the generator breaker.

The lock on the main breaker is key retaining so when its turned on the generator breaker is locked open by the same key. You would have to open the main breaker to remove the key. Take the key to the generator breaker to close it.

I will look into this system.

Cheers

 

[212sparky]

The best, safest and code compliant way would be run a cable from the gen set to an interlock in both panels. Or create an emergency panel that has a transfer switch and you move your loads you need powered into that panel.

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[Coug]

As far as I know, there isn't any legal/approved method of "backfeeding" an electrical panel. As has been stated, only using a proper transfer switch or interlock in the breaker panel can a generator be safely/legally used to power your household loads.

What size generator are you using to power your house/shop?
This information is important because there are some methods that have a limit to how much current can be utilized. 30 or 50 amps are common for interlock setups (and finding an inlet plug larger than 50 amps can get pretty expensive)

One example of the above

GenerLink, Backup Generator | Global Power Products

(check your local utility company to see if they even allow this type of switch, as some utilities don't, and the utility company tends to get a little pissy if you break their seals and mess with their stuff. Other issue is it's only 200 amp rated, you have 2 200 amp panels so that likely means you have 400 amp service))
A transfer switch mechanism that mounts in the utility meter socket, rated for either 30 or 40 amps. If you're only running a 5kw gen, the 30 amp is fine, running a 10k would require the 40 amp plug (and even then you don't want to load it up to 10kw constant load)

Larger than those you'd want some type of either manual or automatic transfer switch between the meter box and your panels. As I mentioned above, the fact that you have 2 200 amp panels likely means you have 400 amp service, which means you would have to get a 400 amp transfer switch installed.




Probably the cheapest thing you could do is run your new cable (or repurpose the cable you have going to the 70 amp panel in the shop if the generator isn't too large of output for it) and then split it off to power interlock switches in both of your 200 amp panels.



Final advise (and disclaimer), I don't know your local codes and such, so you are better off contacting a local to you licensed electrician to see what options actually meet your local codes and regulations, as well as any permits that are supposed to be filed before doing any electrical work

 

[Scoobyshep]

As far as I know, there isn't any legal/approved method of "backfeeding" an electrical panel. As has been stated, only using a proper transfer switch or interlock in the breaker panel can a generator be safely/legally used to power your household loads.

What size generator are you using to power your house/shop?
This information is important because there are some methods that have a limit to how much current can be utilized. 30 or 50 amps are common for interlock setups (and finding an inlet plug larger than 50 amps can get pretty expensive)

One example of the above

GenerLink, Backup Generator | Global Power Products

(check your local utility company to see if they even allow this type of switch, as some utilities don't, and the utility company tends to get a little pissy if you break their seals and mess with their stuff. Other issue is it's only 200 amp rated, you have 2 200 amp panels so that likely means you have 400 amp service))
A transfer switch mechanism that mounts in the utility meter socket, rated for either 30 or 40 amps. If you're only running a 5kw gen, the 30 amp is fine, running a 10k would require the 40 amp plug (and even then you don't want to load it up to 10kw constant load)

Larger than those you'd want some type of either manual or automatic transfer switch between the meter box and your panels. As I mentioned above, the fact that you have 2 200 amp panels likely means you have 400 amp service, which means you would have to get a 400 amp transfer switch installed.




Probably the cheapest thing you could do is run your new cable (or repurpose the cable you have going to the 70 amp panel in the shop if the generator isn't too large of output for it) and then split it off to power interlock switches in both of your 200 amp panels.



Final advise (and disclaimer), I don't know your local codes and such, so you are better off contacting a local to you licensed electrician to see what options actually meet your local codes and regulations, as well as any permits that are supposed to be filed before doing any electrical work

Backfeeds can be done legally with an interlock (these are used on a panel with a main breaker, its typically a bolt on breaker slide) and feed breakers need to be either bolt in or have an additional means of anchor to the buss.

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[Coug]

Backfeeds can be done legally with an interlock (these are used on a panel with a main breaker, its typically a bolt on breaker slide) and feed breakers need to be either bolt in or have an additional means of anchor to the buss.

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So a "backfeed" is where you take an outlet, such as the dryer outlet, and make a cord so that instead of power coming out of that outlet, you are feeding power into it.
When you have an interlock you are specifically preventing a circuit from being connected to the rest of the panel without the main breaker being off. It does require use of some type of a plug inlet, and I've even seen people use dryer plugs and a double ended cord, but the presence of the interlock means it is no longer a backfeed but an inlet circuit. Once the circuit is no longer capable of being used as a feeder circuit you can't backfeed into it.


I know it's just a matter of viewpoint/terminology, but I will stand behind my statement of "there is no legal/safe method of backfeeding an electrical panel.