Generator Transfer Switch Amperage rating

I can run my 2500 sq ft house on the 5500W gas generator. I do not have to run just 5 or 6 circuits. I do have to shut off the central AC. And I must configure my hybrid electric water heater to "max efficiency mode" which only runs the 600w heat pump and not the 4500w heating element.

Other than that, I can run my well pump, window AC, 2 chest freezers, fridge, computers, TV and all the LED lights I want.

Do you have a whole house transfer switch, or like i am, backfeeding the panel?
 
During the Derecho I fed 240V from the 5600W generator to the 30A AC circuit breaker via a #10 three-wire plug and socket and witched off the 200A circuit breakers at the top so as not to feed AC into the power system.

This was not an "up to the code" wiring situation but it got us through the power outage. I had all of the appliances functioning during the week the power was out.
 
During the Derecho I fed 240V from the 5600W generator to the 30A AC circuit breaker via a #10 three-wire plug and socket and witched off the 200A circuit breakers at the top so as not to feed AC into the power system.

This was not an "up to the code" wiring situation but it got us through the power outage. I had all of the appliances functioning during the week the power was out.

I do the same, i have a 240v outlet in the garage fed with 2 legs of #6 each on a 50amp breaker. I can run the rv if needed from the house, or backfeed the entire house managing my loads so the little 4375 can keep up. 240v for the well. I trip the mains as well to not power the lines.
 
Do you have a whole house transfer switch, or like i am, backfeeding the panel?

I have an external meter + breaker box. In that box are the 200A main breaker, the AC compressor breaker, and 2 generator breakers. With an interlock to prevent the main from being selected "on" when either of the 2 generator breakers are on.

So, it is not a "backfeed" but rather a choice of 3 power sources.
 
Thanks for the kind attention and comments. For those still interested, here is my main panel with a 200 amp main breaker. It is totally filled with 60 breakers. Then I have the pony panel with another 20 breakers, joined by the electrical cable shown. The electrician roughed in a cable from a box outside close to where the portable generator would be parked and ran it into the basement furnace room where the panels are.

View attachment 30598View attachment 30599View attachment 30600View attachment 30601

Those pics help alot. That is quite the distribution. Square D QO series panel and breakers will serve you well. I can't make out what size the conductors are in the cable. What does it say on the jacket? Are the conductors aluminum, or is it just the lighting throwing me off?
 
The conductors are aluminum, made by Alcan. Here are some further pics. Thanks Jim.

BF43F96E-6028-459A-BA87-971D4C6435FB.jpeg2679130D-BD2C-40F6-ABD1-AD6DAFAAD69D.jpeg300E4737-5344-4961-8586-4B95B5ADDCE2.jpeg
 
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If I may, a 'some of the circuits' solution is horrible for a home. I have been paid to move circuits around to suit what the last guy thought was best, etc. - the wife didn't agree. It also typically means splices, etc in main panel to get to mini panel.
Bite the bullet, buy the right transfer switch for the house, mark things up so you remember you have only 30 amp (?) service on generator. You can turn off what is automatic that you have to prevent operation.
For instance, a freezer and a fridge would commonly be 2 of the 6? breakers allowed by some mini panels. With a whole house solution, you can cycle this freezer, that frig, that room for hobbies, this room for sleeping, etc. The right parts would be an investment that pays off.
If the next guy has a 10, 15, 20 kw you're already set - maybe a plug change.
 
I certainly am OK with the whole house solution but with a 200 Amp service will I find a transfer switch that meets the codes rather than back feeding? By the way, here is a shot showing AWG 2 Aluminum for the roughed in cable from the future generator location. Thanks.

4CB63159-59A8-4F91-96DF-D90DC7F95E2F.jpeg
 
If I may, a 'some of the circuits' solution is horrible for a home. I have been paid to move circuits around to suit what the last guy thought was best, etc. - the wife didn't agree. It also typically means splices, etc in main panel to get to mini panel.

Yep. Wire nuts or Polaris connectors that no one ever checks for tightness and are hidden in the load center. I won't do it in my own house.
 
I certainly am OK with the whole house solution but with a 200 Amp service will I find a transfer switch that meets the codes rather than back feeding? By the way, here is a shot showing AWG 2 Aluminum for the roughed in cable from the future generator location. Thanks.

View attachment 30896
NMD90 in #2 AL is good for 100 amps at 90 degrees C. Not sufficient for carrying the full load. You would need a double throw two pole switch like the one in the pdf attached. You don't have to pay the $2k list price. They regularly hit eBay new in box around $400-$500.
 

Attachments

  • Eaton - PowerEdge.pdf
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Just to clarify, the NMD90 #2 cable is the roughed- in cable from the generator to the future transfer switch, so it would never see 200 amps, correct? It would just see the max output of the generator. So if I understand, the main service would enter the transfer switch, then a 200 amp rated cable would go from the transfer switch to the main breaker box that has a 200 amp breaker, then onward to all the original breakers. I’m downloading a photo of the main service cable which comes up from the floor (it’s inside a underground conduit from the edge of my lot, a couple of hundred feet away). That cable is humongous. For some reason it takes quite long to download from IPhone via the Cloud. Hang on.
 
Just to clarify, the NMD90 #2 cable is the roughed- in cable from the generator to the future transfer switch, so it would never see 200 amps, correct? It would just see the max output of the generator. So if I understand, the main service would enter the transfer switch, then a 200 amp rated cable would go from the transfer switch to the main breaker box that has a 200 amp breaker, then onward to all the original breakers.

You are correct. Lost my train of thought yesterday. Too many distractions.
 
Here i
Just to clarify, the NMD90 #2 cable is the roughed- in cable from the generator to the future transfer switch, so it would never see 200 amps, correct? It would just see the max output of the generator. So if I understand, the main service would enter the transfer switch, then a 200 amp rated cable would go from the transfer switch to the main breaker box that has a 200 amp breaker, then onward to all the original breakers. I’m downloading a photo of the main service cable which comes up from the floor (it’s inside a underground conduit from the edge of my lot, a couple of hundred feet away). That cable is humongous. For some reason it takes quite long to download from IPhone via the Cloud. Hang on.
Here is the photo of the cable and the main breaker box. I guess I see it would be difficult to get a transfer switch box physically between the cable end and the main breaker box. Thanks to those still reading this thread.

69398AF7-1A9B-4400-BE26-8CFAC95B7A26.jpeg
 
The typical generator transfer switch with 6 or 8 circuits has BX cable coming out of it with 12 or 16 wires in it. It goes to a single circuit breaker box. Each circuit you want to power via generator uses 2 wires in this BX cable. One to switch and one back. Hard to connect it to a main and a branch circuit breaker box.

You need to install a small branch box and permanently move the 6 or 8 circuits you want to power with generator. Power that branch box with a 50 amp circuit off main circuit breaker box. And setup a switch or lockout to be able to power the small branch box via generator.
 
I have run my house on the common very quiet 3.2K. I have wood heat, Changed the water heater to 110 V picking the legs with the lightest load. Some hot water, enough for a military type shower. 6K BTU air con for the master bedroom. Attic fan for the rest of the house. Frost free refrigerator, chest freezer. Ran for over a 4 at least 5 times so far. Have shed all other loads to cook. washer will run, have clothesline for drier. Life was acceptable, best part is 5 gallons of gas a day. Neighbors 7K burned 15 gallons, and was noisy.

Rod
 
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