Need advise how to power HVC to 12kW portable generator


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Old 02-25-21, 10:06 AM
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Need advise how to power central AC to 12kW portable generator

Hello experts,

i bought a 12Kw Pulsar G12KBN (Amazon link )portable generator with a 50Amp outlet to power my house and my 4ton AC during Louisiana storm seasons (last year we had 6 storms) and i'm looking for best recommendation on how to go about hooking it up to my house. All youtube videos out there are pretty easy to follow but they have regular panels with Main breaker shutoff in them. (Not my case) which is why i'm struggling to find an answer.
My house has a Main Panel outside with the meter on it and including the breaker to the sub-panel, Oven and AC and a sub-pannel inside the garage, but i can't find the main breaker. Please advise how should i go about installing a transfer switch or do i need an interlock switch? or what do i need in my case? If you can draw a diagram that would be nice. Attached are pictures of my panels.









 

Last edited by Youdjin; 02-25-21 at 10:38 AM.
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Old 02-25-21, 11:45 AM
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Install an generator transfer switch. It will allow you to run off the power company or generator but not allow both to be connected at the same time.
 
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Old 02-25-21, 12:05 PM
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Thx Dane, any recommendation on what king would i need for this and how to wire it?
 
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Old 02-25-21, 02:36 PM
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In my mind there are two types of manual transfer switches. One type goes between the meter and everything else so your generator could feed everything. If your case this would probably be the more expensive option to install. The other type looks like a breaker panel and you would pick certain circuits in your house to be moved to the new transfer box's breaker panel.

Installing a transfer switch is something that requires following NEC (National Electric Code) a permit and inspection. First, you can check with your inspections dept and see if they will allow you as the homeowner to perform the work. Then do some research and reading. Bonding is probably the trickiest part.
 
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Old 02-25-21, 08:57 PM
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You've got a toughie there. Probably on the front of the house too.

You have three main breakers. Oven, A/C (outside unit only) and inside panel.
That's a big panel inside to only be on a 100A breaker.
You need to transfer at least the 100A and the A/C breaker to get A/C.
There is no way to transfer to a generator with what you have there.

If that was me I'd pull the meter/breaker combo out and replace it.

You'll need a 200A meter pan and a 200A breaker panel with interlock.
A 200A circuit breaker panel with a 200A main breaker, a 2P50 for gen transfer, a 2P40 for A/C and a 2P40 for the oven.

You'll probably need an electrician with this job.

Some additional info.....
A Square D 200A QO weather proof panel - QO1816M200FTRB
It has a 200A main and places for four 2P breakers.
You'd need to check on an interlock kit.

Another possible choice..... QC816F200C
This is a meter/panel combo. Enough space.
Need to check for poco approval of ring type.
Need to see if an interlock is available.
 
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Old 02-26-21, 04:44 AM
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Would two whole house transfer switches work? (The kind with one big toggle instead of several little toggles.) Both could be mounted next to the meter box.

One would be in the line to the AC unit and the other one would be in the line to the house panel.Because they would be downstream of the service panel (meter box) there would be no need to pull the meter.

Are manually flipped transfer switches of this kind all that expensive?

(You would need a third transfer switch for the ovens, or perhaps you might be using propane stoves for all cooking during the outage.)
 
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Old 02-26-21, 04:52 AM
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A whole house transfer switch would be the most work & money. I think it would need a new meter base passing through the 200 amp transfer switch ($430) and inside to feed the existing panel and a new panel handling the large 240 loads. The bulk of the money would be redoing a lot of the existing meter base and panels.

Or, use a smaller transfer switch that only handle 8 or 12 circuits and move only those circuits to the transfer panel. I just saw a ten circuit switch with receptacle for the generator for $390 while a single circuit one intended for a furnace is $80.
 
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Old 02-26-21, 06:15 AM
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Ouch, thx for detailed explanation Pete.
 
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Old 02-26-21, 06:25 AM
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AllanJ, my stove is on natural Gas and i don't need the oven during emergencies, i only need to power the inside panel where the furnace is located and the AC Condensing Unit which is obviously located on the Outside panel.
 
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Old 02-26-21, 09:57 AM
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It's an interesting setup. Not something I've ever done.
May have been a less costly way to do the job.
An outside disconnect would have been required if the inside panel was more than approx 5'-10' from the meter.

Typically that would have been a 200A meter pan with a 40 circuit 200A panel inside.
The oven and A/C condenser would be connected inside the main panel.
 
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Old 02-26-21, 10:14 AM
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Pete, the inside pannel is just on the other side of the wall in the garage, i would say maybe 3-4 ft of cable between them, and pretty much all the houses in my community have the same setup.
 
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Old 03-20-21, 01:35 PM
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Need advise how to power central AC to 12kW portable generator

Please let me know if this will work or not. So i bought a 200A panel, with a main disconnect. If i move the 100A breaker for the inside panel and the 40A breaker for the AC into this panel and i add a 50A breaker for the generator receptacle with an interlock kit, then i connect the two panels with a 200A wire via a 200A breaker that i will add back to the main panel, will that be posible? and my second question how would i wire the neutral and the ground between the two panels? As far as i can tell the meter panel has a bonded Neutral and ground.



 
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Old 03-20-21, 03:24 PM
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You're going to have to extend the wiring from each circuit out to the new panel.
You'll need to splice on two # 8's for the range.
You'll need to splice on two # 8's for the A/C condenser.
You'll need to splice on three 1/0's ?? for hots and neutral.

Technically..... the ground wires from each circuit also need to be moved out to the new panel.
 
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Old 03-21-21, 09:33 AM
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Can i leave the Oven in the main panel and not move it?
 
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Old 03-22-21, 07:22 AM
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What I am not seeing is a positive interlock to keep generator power from feeding back into the power lines. Inspectors generally view "home-brewed" interlocks with a jaundiced eye. Many (if not most) will not even consider one unless it is listed for the purpose.
 
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Old 03-22-21, 02:43 PM
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Interlock: prevents several very big linemen from beating the crap out of you when you forget to throw the right switches and energise the line they're working on. Also prevents you from being sent to jail for manslaughter. Well worth installing one, I'd say.
 
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Old 03-22-21, 10:35 PM
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Yes, the interlock kit will definitely be there, i just didn't mention it in the drawing. Now one guy told me i don;t need a 200Amp panel, i only need a 100A panel, is that true? which one would work best in my case?
 
 

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