homemade manual transfer switch

[enireh]

I'm thinking about doing a manual transfer switch. I have a 400 amp service with two 200 amp panels at the meter, and four sub panels one for the pool, the well, and two for the house. I want to make a generator outlet with a disconnect so when the disconnect is engaged the outlet can be used for the generator (when the power is out). I turn off both 200 amp main breakers and leave the well, and two sub panel breakers on so that will power up various circuits I leave on in emergency times like fridge, freezer, some lighting, and the well and septic system. I will be making joints at the sub panel main, and the well breaker then feeding into line side of the disconnect.
sub panel main is in one of the main panels at meter

thank you

 

[readydave8]

I'm thinking about doing a manual transfer switch. I have a 400 amp service with two 200 amp panels at the meter, and four sub panels one for the pool, the well, and two for the house. I want to make a generator outlet with a disconnect so when the disconnect is engaged the outlet can be used for the generator (when the power is out). I turn off both 200 amp main breakers and leave the well, and two sub panel breakers on so that will power up various circuits I leave on in emergency times like fridge, freezer, some lighting, and the well and septic system. I will be making joints at the sub panel main, and the well breaker then feeding into line side of the disconnect.
sub panel main is in one of the main panels at meter
I
thank you

I may be misunderstanding how it works but that doesn't sound like a transfer switch

 

[enireh]

I may be misunderstanding how it works but that doesn't sound like a transfer switch

 

[enireh]

the generator outlet is connected to the load side of disconnect, the wires from sub panel main and well main will be tied into line side of disconect
when the power goes out the two main breakers on the two main panels at meter will be shut off. The generator will plug in to outlet and the disconnect will be engaged thus sending power to the two main panels and sub panels. only some lighting, and fridge, freezer outlets will be on in the house and the well and septic tank

 

[suemarkp]

What happens if you turn the main breakers back on, with power from the utility, while the generator is connected? I also hope you have a generator inlet and not an outlet. And aren't the sub panel main and well main connected to the LOAD side of your existing main disconnect?

 

[enireh]

What happens if you turn the main breakers back on, with power from the utility, while the generator is connected? I also hope you have a generator inlet and not an outlet. And aren't the sub panel main and well main connected to the LOAD side of your existing main disconnect?

 

[winnie]

What you describe _can_ be done, but to do it legally would be expensive and difficult.

The key principal of a transfer switch (manual or automatic) is that you cannot have both sources of power (utility mains and generator) on at the same time.

In your setup, how do you ensure that the connection to mains power is disconnected when the generator disconnect is turned on? This cannot simply be 'I know what to do'; there has to be an automated method that prevents both sources of power from being on at the same time.

-Jon

 

[don_resqcapt19]

Sounds like a violation of 702.5(B) as there is nothing to prevent th inadvertent interconnection of the generator and the utility.

 

[enireh]

I would not turn the main breakers on while the utility power is hot. The sub panel main and the well main are in the main panels

 

[enireh]

I would not turn the main breakers on while the utility power is hot. The sub panel main and the well main are in the main panels

 

[enireh]

EZ-Connect 100 or 200 amp Whole House Manual Transfer Switch EZC - The Home Depot

EZ-Connect transfer switch is for portable generators and allows the homeowner to feed their entire electrical panel up to the capacity of their generator. The EZ-Connect is UL Listed and prevents dangerous

www.homedepot.com

this is the same thing

 

[suemarkp]

I would not turn the main breakers on while the utility power is hot. The sub panel main and the well main are in the main panels

That's not how a transfer switch is supposed to work. It has to work for dumb people who don't know better. If it is possible for the utility and generator to energize the panel at the same time, it is incorrect. You need a positive interlocking means between the two power sources, not a procedural one.

 

[winnie]

EZ-Connect 100 or 200 amp Whole House Manual Transfer Switch EZC - The Home Depot

EZ-Connect transfer switch is for portable generators and allows the homeowner to feed their entire electrical panel up to the capacity of their generator. The EZ-Connect is UL Listed and prevents dangerous

www.homedepot.com

this is the same thing

Electrically it is the same thing.

The key difference is that in the transfer switch above you _cannot_ have both breakers on at the same time. The system is mechanically constrained to have only one or the other breaker on at any given time.

If your subpanels have main breakers then simple mechanical interlocks are available, such as https://www.geninterlock.com/wp-content/uploads/2020/08/SIE-P2-Instructions.pdf The unit blocks the operation of the generator breaker unless the main is turned off and a chunk of metal slid aside.

-Jon

 

[enireh]

Electrically it is the same thing.

The key difference is that in the transfer switch above you _cannot_ have both breakers on at the same time. The system is mechanically constrained to have only one or the other breaker on at any given time.

If your subpanels have main breakers then simple mechanical interlocks are available, such as https://www.geninterlock.com/wp-content/uploads/2020/08/SIE-P2-Instructions.pdf The unit blocks the operation of the generator breaker unless the main is turned off and a chunk of metal slid aside.

-Jon

 

[enireh]

thank you

 

[Little Bill]

thank you

@enireh
Why do you keep quoting a post, not typing anything, then , replying in a separate post?
It is very confusing and hard to keep up with.

 

[Jraef]

the generator outlet is connected to the load side of disconnect, the wires from sub panel main and well main will be tied into line side of disconect
when the power goes out the two main breakers on the two main panels at meter will be shut off. The generator will plug in to outlet and the disconnect will be engaged thus sending power to the two main panels and sub panels. only some lighting, and fridge, freezer outlets will be on in the house and the well and septic tank

I would not turn the main breakers on while the utility power is hot. The sub panel main and the well main are in the main panels

There's the rub. If you forget to open the main breaker when you turn on your generator, you can kill a utility line worker somewhere off in the distance and not even realize it. A real transfer switch has mechanical safeguards to prevent that from happening. You are not allowed to "roll your own", there is someone else's life at stake here.

 

[McLintock]

Sounds like to me you really need to get a standby generator, maybe a 12kw, and a ATS with a 8 space panel. Then YOU would not have to worry/ take the liability of forgetting to turn that breaker off and killing some lineman, who is trying to restore YOUR power.

We have installed a couple of MTS but most ATS, I am a big fan of a ATS over a MTS


“ shoot low boys their riding shetland ponies”

 

[James L]

I'm thinking about doing a manual transfer switch.....

thank you

I don't really see a question.
Just "I'm gonna do this. Thanks"

Like taking a bow

For real, that's a very busy sequence you've proposed. What happens if you get down sick, and we have to call in your nephew to manage the power during a storm until you get better?

Brother, I know that we all know how to manage something like that, but we're all human. We're subject to lapses in memory.

There's a reason that transfer has to be guaranteed.
It ain't worth the risk to save a little bit of money.

 

[enireh]

I don't really see a question.
Just "I'm gonna do this. Thanks"

Like taking a bow

For real, that's a very busy sequence you've proposed. What happens if you get down sick, and we have to call in your nephew to manage the power during a storm until you get better?

Brother, I know that we all know how to manage something like that, but we're all human. We're subject to lapses in memory.

There's a reason that transfer has to be guaranteed.
It ain't worth the risk to save a little bit of money.