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Transfer Switch

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Linghunt

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#31
I was poking around some, and there is a big market for "transfer switch gear"

Many different directions to go. some of the stuff looked like junk, other good.

One approach was with breakers and interlock panels



https://skyelectric.org/blog/generator-oneline-with-inlet-and-bypass/

Many others use Contactors and feedback to detect Line power along with bells and whistles.



http://www.hardydiesel.com/transfer-switches/asco-185-series-transfer-switches.html




2 main points from my perspective

-1- Making sure the Main is disconnected when your Generator is powering the house, you have utility guys working on the lines and you don't want to FRY one of them.

-2- Don't be exposed to live switch gear without a steel barrier.

Lots of different ways to skin a cat here. I would think the electrician you have could direct you to a local supplier. The Electrical Part house guys should be able to direct you as well. Getting an in person referral is best. Too many out there that might sell junk.

Go to supply house in the early morning, you can get some good homemade burritos the local lady makes for the crews gets parts for the day.

Having lots of folks waiting for parts gives you more people to talk to as well.

I don't recommend either of these site links, they just had the best illustration pictures.

This thread is interesting dialog on the subject.

http://forums.mikeholt.com/showthread.php?t=185238
 

juiceclone

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#32
he is looking for an emergency transfer switch to be used to disconnect from a DEAD mains supply, isolate the home/shop?, and allow connection to a backup generator. NOT for hot switching
 

tq60

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#33
I did an Ebay search found this one. This is type switch I was thinking of.

http://www.ebay.com/itm/Square-D-Ge...844213?hash=item3f8779c575:g:Q6oAAOSwIwJZii8k

I got a thick Square-D catalog, (others too) if you want a part number to look for or specs on a number let me know. The paper book works much better than online versions for me at least.
This looks like the units we had...my area had 300 or so.

They are designed for what the op needs and should be readily available.

For this project one plan only....Do it with task designed, approved parts.

This is MTS but ATS is better but much more expensive.

Sent from my SAMSUNG-SGH-I337Z using Tapatalk
 

Linghunt

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#34
he is looking for an emergency transfer switch to be used to disconnect from a DEAD mains supply, isolate the home/shop?, and allow connection to a backup generator. NOT for hot switching
I agree that was part of original message.

He had a frequency of use [ once a month ]. If you have same Emergency 12 times a year, not really an "Emergency" is how I read it.

Not for use in Hot switching was the goal, but power grid could just turn on, the main circuit breaker needs to be off before he does the switching. Hope he remember to do it each time he does this. Perhaps a teenage son or wife will do it, if he's sick or not there at the time.

Point being there can lots of "what if's" along with a upgrade not specified clearly. He did want it legal in compliance thou. The local technical boots on the ground approach seemed like a good start.

My Apologies, if I went to far into left field or stepped on any toes.
.
 

tq60

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#35
I agree that was part of original message.

He had a frequency of use [ once a month ]. If you have same Emergency 12 times a year, not really an "Emergency" is how I read it.

Not for use in Hot switching was the goal, but power grid could just turn on, the main circuit breaker needs to be off before he does the switching. Hope he remember to do it each time he does this. Perhaps a teenage son or wife will do it, if he's sick or not there at the time.

Point being there can lots of "what if's" along with a upgrade not specified clearly. He did want it legal in compliance thou. The local technical boots on the ground approach seemed like a good start.

My Apologies, if I went to far into left field or stepped on any toes.
.
An emergency transfer is any unplanned need.

The argument above brings up something...

If the local power is not reliable then one needs to address that as a seperate issue but these things happen and if one had a frequency of use higher than 3 times a year then the ATS is the only way to go as it protects automatically.

If power goes out one time a year and you have a need for power but no generator then it is an emergency.

If it drops every month and you need power it still is an emergency but poor planning.

Proper system design would have little if any loss of use as the generator would come online in a reasonable period to restore those loads and ups equipment and supplement generator start time.

But almost everyone in this business fail in their design as they assume the generator will start.

Had to bypass ATS too many times to connect portable units when main failed.

So if the need is for medical insure you have backup to the generator.

A ups works if it can support the load.

Battery backup works but the battery must be large enough to supply the load for the time it takes to determine the generator is needed but failed and get it replace as well as the time it takes to refuel to restore some operation when it runs dry.

A 5 gallon jeep can could buy enough time to get a truck there with delivery.

Sent from my SAMSUNG-SGH-I337Z using Tapatalk
 

Wireaddict

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#36
Matt, too bad your (2) 200A subpanels are so far from your genset. A 40KW, 240V, single phase generator will supply 167A so a 200A transfer switch, automatic or manual, sounds like a good fit. Is there any way you you could move all your critical circuits to ONE of your subpanels? That way you could install a (200A) transfer switch near your subpanel containing the critical circuits so as to keep them on (provided you can run the feed from your genset there.) Just a thought...
 

GaryLa

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#37
I think transfer switches are too expensive and limit you too much.

In my past 3 homes, I've installed a 3-position Knife switch. Up = Street Power, Center = No Connect (for starting the generator), Down = Generator.

During power outages I can power anything at any time without regard to what circuits are in a transfer box...

Also, I have never used a generator large enough to power my whole house. Therefore, before starting my generator I just shut off the breakers I don't want powered.

Another advantage is that the smaller generator can be used to power each refrigerator or A/C or whatever by taking turns with their individual breaker on.

Also, you can have an electrician install the knife switch without violating any codes. In most counties, you have to have a generator large enough to 100% service connected circuits. So if you want whole house, bend over.

The knife switch, in my opinion, is the best option. In my first house, I had a 3500 watt generator. With the knife switch I was able to power the fridge once every couple of hours, and run the TV and some lights. I turned off the breakers to 220 feeds for the water heater and other unneeded fuel hogs.
 

GaryLa

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#40
My knife switches are always: 1) installed by qualified personnel, 2) large enough for the entire house's service, 3) name-brand components.

They are large panels and look very commercial. The point is that they do not require an inspection of your generator to be approved.
 

GaryLa

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#41
Regarding knife switches:

1) install with qualified personnel only
2) must be large enough for the entire house's service
3) use only name-brand components

They are large panels and look very commercial.

The idea of buying some piece of junk off ebay would make me nervous. Also, when you sell the house it may have to be removed. My last two houses had 325 Amp 3-position knife switches installed at a cost of about $1000.00.

The ones I get installed are perfectly legit and pass local code requirements. The point is that they do not require an inspection of your generator to be approved.
 
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