Generator sizing and recommendations

[Hot shot]

Happy new year to everyone
It’s been a while since I’ve posted but I do know this is the place to get help with just about anything from very knowledgeable folks
Im trying to determine how big of a generator to get. Have a pretty good idea but want some opinions not looking for a whole house one
I have a 1500 sq ft rancher. For the last 10 yrs been using a Briggs and Stratton 5250 running watts 7350 surge. Generator runs from my 12x28 shed to main panel in the house through a 30 amp plug to sub panel. Plug and panel are inside shed. 60 amp double pole breaker in sub panel to 60 amp double pole breaker in main panel in house. 6 gauge copper wire
Don’t need to run hvac. Have a gas log fireplace and a couple ac window units if necessary. 3 main reasons for a bigger one
We have a lg gas stove. No problem for stove top cooking. Cooking in the oven is a different story. Oven doesn’t work on generator power The oven gas valve opens when the igniter reaches a certain temperature. When oven is first cut on it needs a minimum of 116 volts for 3 or 4 minutes for igniter to work. I’m only getting 116-117 volts on house receptacles when generator is on. 123 volts when power company power is on. #2. Sometimes when well pump comes on lights will dim for a second
#3 on generator power microwave doesn’t come up to full power. It is about 15 years old
Tomorrow just to see I’m going to run an extension cord from microwave to 20 amp receptacle on generator. I will only run electric hot water heater when nothing else is on. And power will have to be out for 3 or more days before I run water heater. The biggest draws during the day are
Well pump-20 amp double pole don’t know for sure but guessing a 1 1/2 hp motor
Septic pump-20 amp single pole
Coffee maker
24 cu ft fridge in kitchen tag inside of fridge says 6 amps
Upright freezer in kitchen 5 amps
Older 18 cu ft fridge on porch 7 amps
Maybe an air fryer. I’ve been unplugging fridge and freezer when using air fryer
Lights. All inside lights and outdoor lights are leds
A couple tvs
Night time in winter 3 oil filled radiators for bedroom heat.
2 days before Xmas power went out for 24 hours when my wife had several things to bake. Bad timing got down to 8 degrees that night
I’m thinking something like 9000-11000 or 10000-12000 wattage. Brand of generator to get or stay away from. I think all I have to do is swap the 30 amp plug for a 50 amp. Right or wrong?
Biggest outage we had was 2 years ago in February. Ice storm. Generator ran for 7 days. Not at night though
Didn’t mean for this long of a post. Just trying to cover all the bases
Thanks

 

[pattenp]

The only thing I have to offer is your setup powered via a subpanel sounds to be not NEC compliant and dangerous.

 

[Hot shot]

Tell me what’s wrong
If it’s not safe I want to know

 

[Hot shot]

My apologies.
I didn’t explain the sub panel right
The generator plug wiring goes to a double pole 30 amp in the sub panel
The sub panel has a 100 amp double pole main breaker so I used that since it came with the panel
No 60 amp double poles in the sub panel
Obviously if I change the 30 amp generator plug to a 50 amp I would also change the 30 amp double pole to a 50 amp double pole

 

[loganb]

It doesn't sound like there is an interlock mechanism preventing you from backfeeding power from the generator back into the grid. You manually throwing a disconnect at the pole or the main breaker in the main panel is not code compliant. There are mechanical interlocks for the main panel that puts the generator circuit in one of the top spots but that won't work if you're feeding a subpanel

 

[pattenp]

In addition to what loganb said, it sounds like you are back feeding through a standard outlet possibly using a cord with male plugs on both ends. I do hope I'm wrong and you are at least using a proper generator power inlet.

 

[Ole Slewfoot]

Run the oven its own cord temporarily...if it now works, upgrade the cable not the generator?

 

[wyliesdiesels]

Yikes.

How are you powering the shed subpanel, with utility power, and back feeding the main from the subpanel, with the generator, without possibly back feeding the grid?

There is no way to do this in a safe manner....

The generator feed needs to go direct to the main panel and you need an interlock...

 

[wyliesdiesels]

It doesn't sound like there is an interlock mechanism preventing you from backfeeding power from the generator back into the grid. You manually throwing a disconnect at the pole or the main breaker in the main panel is not code compliant. There are mechanical interlocks for the main panel that puts the generator circuit in one of the top spots but that won't work if you're feeding a subpanel

You wouldnt be able to use an interlock with this setup unless you didnt want to power the shed with utility power...

 

[wyliesdiesels]

My apologies.
I didn’t explain the sub panel right
The generator plug wiring goes to a double pole 30 amp in the sub panel
The sub panel has a 100 amp double pole main breaker so I used that since it came with the panel
No 60 amp double poles in the sub panel
Obviously if I change the 30 amp generator plug to a 50 amp I would also change the 30 amp double pole to a 50 amp double pole

Doesnt matter. There is no way to lock out the utility feed in the main when back feeding with a generator and still have the capability to feed the shed with utility power when the generator is not in use.

Your setup is very dangerous and needs to be fixed

Generator feed needs to go direct to the main panel...and then you need an interlock

Also, if youre using a receptacle to connect the generator to the subpanel that means youre using a suicide cord with double plugs... double yikes

 

[Hot shot]

Here’s what I have
When I Run generator the only breakers that are on in sub panel are 100 amp main and 30 amp dp from power inlet box
Flat grey wire is the 6 gauge from sub panel in shed to main panel in house. It is a 50’ run in conduit in the ground. I agree with Yal about an interlock. I’m the only one that goes in the panel
My wife will not touch it. It is locked in my brain that the very first thing I do before starting anything is to cut 200 amp main breaker off in house panel.
Is the 6 gauge big enough for a generator with 50 amps
Would a 50 amp generator get my voltage up to 120 in the house. Either 8000 or 10000 running watts
The black cord runs from power inlet box to dp 30 in sub

 

[wyliesdiesels]

So many things wrong here

Turning off the main is not only not code compliant but it creates a dangerous situation.

that black cordage is not kosher as it is not building wiring. Code does not permit cordage to be used in place of in wall wiring. What guage is it? Looks like #10...

That gray UF cable you have looks to be 3 conductor which means you cant do 120/240v with it... only either 120v or 240v but not both....

At least youre not using a suicide cord...

 

[Hot shot]

Pic

 

[Hot shot]

If the black cord is not the proper wire can you show me a pic of what I should’ve used

 

[theoldwizard1]

Your setup is very dangerous and needs to be fixed

Generator feed needs to go direct to the main panel...and then you need an interlock

ABSOLUTELY !

If you want to keep that subpanel it needs to be reconfigured with an interlock so that it is IMPOSSIBLE to have PoCo power and generator power on at the same time.

The proper cable from the shed to the house would be something like MHF, probably 2-2-2-4., Depending on the size of the generator. If it is true 10KW unit 2/0-2/0-1-4 would be required. MHF must be run INSIDE OF CONDUIT WHEN ABOVE GROUND !

If you upgrade the wire to the proper size and install a proper interlock, your wife might be able to use the oven with your current generator if nothing else is turned on.

 

[mm08822]

ABSOLUTELY !

If you want to keep that subpanel it needs to be reconfigured with an interlock so that it is IMPOSSIBLE to have PoCo power and generator power on at the same time.

The proper cable from the shed to the house would be something like MHF, probably 2-2-2-4., Depending on the size of the generator. If it is true 10KW unit 2/0-2/0-1-4 would be required. MHF must be run INSIDE OF CONDUIT WHEN ABOVE GROUND !

If you upgrade the wire to the proper size and install a proper interlock, your wife might be able to use the oven with your current generator if nothing else is turned on.

2/0 for 10kw ? How so ??

#2 AL is sufficient.

 

[Snip's]

If your house has an electrical fire that does major damage and you file a claim with your insurance provider.... The first thing they will go for.... Was the work done by a certified electrician and or was it properly done to code....

At which point you will quickly find out if the insurance provider is your friend or enemy......

 

[theoldwizard1]

2/0 for 10kw ? How so ??

#2 AL is sufficient.

50+ ft !

 

[Hot shot]

I remember reading 6 gauge wire was good up to 60 amps
Right or wrong?

 

[Hot shot]

I’m going to do a test
Get generator powering the house
Only cut on receptacle circuits
Check voltage
Would I get a little more voltage swapping the 10 gauge cord to maybe 6 gauge that runs from power inlet box to 30 amp breaker in sub

 

[Hot shot]

I’m going to do a test
Get generator powering the house
Only cut on receptacle circuits
Check voltage
Would I get a little more voltage swapping the 10 gauge cord to maybe 6 gauge that runs from power inlet box to 30 amp breaker in sub
I don’t know what size wire is in the generator cord. Looks the same size as the black one
I guess the voltage drop is in the 50’ run like wizard said

 

[mm08822]

50+ ft !

#2 AL XHHW @ 75C is good for 90A with a 3% VD for 130'. OP has only mentioned 30/50A and worst case, a new gen @ 11-12KW. 50' has virtually no impact using #2 Al.............never mind 2/0 AL.

Run the numbers.

 

[wyliesdiesels]

ABSOLUTELY !

If you want to keep that subpanel it needs to be reconfigured with an interlock so that it is IMPOSSIBLE to have PoCo power and generator power on at the same time.

The proper cable from the shed to the house would be something like MHF, probably 2-2-2-4., Depending on the size of the generator. If it is true 10KW unit 2/0-2/0-1-4 would be required. MHF must be run INSIDE OF CONDUIT WHEN ABOVE GROUND !

If you upgrade the wire to the proper size and install a proper interlock, your wife might be able to use the oven with your current generator if nothing else is turned on.

huh? based on what?

 

[wyliesdiesels]

50+ ft !

50' is nothing for #2 AL MHF... not sure where youre getting your numbers from

 

[wyliesdiesels]

If the black cord is not the proper wire can you show me a pic of what I should’ve used

you need building wire.

either NM-b or THWN....

 

[wyliesdiesels]

I’m going to do a test
Get generator powering the house
Only cut on receptacle circuits
Check voltage
Would I get a little more voltage swapping the 10 gauge cord to maybe 6 gauge that runs from power inlet box to 30 amp breaker in sub

you need to stop and back up. your setup is not code compliant. if you want to power the shop AND the house with the generator, then the generator feed needs to connect to the house panel NOT the shop subpanel. you will also need an interlock.

 

[mike93lx]

Rip it out and start over. This is 100% wrong

Or just say you don't care and let people move onto something else

 

[wyliesdiesels]

Rip it out and start over. This is 100% wrong

Or just say you don't care and let people move onto something else

doesnt seem like he does

 

[Hot shot]

Not powering shed
I flip the breakers in the sub panel off when running generator

 

[mike93lx]

Don't care. Got it

 

[wyliesdiesels]

Not powering shed

I flip the breakers in the sub panel off when running generator

that has no bearing on the dangerous wiring at hand. flipping the sub breakers off doesnt solve the grid backfeed issue.

the issue is the generator feeding the subpanel. to make this compliant the generator feed needs to go directly to the main panel with an interlock on the main and generator breaker.

there is no way to do this properly with the generator feeding the subpanel...

 

[ddurrett896]

Everyone screams interlock when this topic comes up.

The bottom line is MAKE SURE THE MAIN BREAK IS OFF BEFORE YOU DO ANYTHING. Simple enough

 

[mike93lx]

Everyone screams interlock when this topic comes up.

The bottom line is MAKE SURE THE MAIN BREAK IS OFF BEFORE YOU DO ANYTHING. Simple enough

If it was so easy, interlocks wouldn't be a requirement.

One mistake can kill someone working on the power lines, and if they catch you, you'll get your feed cut

 

[pattenp]

Everyone screams interlock when this topic comes up.

The bottom line is MAKE SURE THE MAIN BREAK IS OFF BEFORE YOU DO ANYTHING. Simple enough

Not simply enough. Apparently you are missing the point.