How to wire in a backup generator?

Question

Growing up in the mountains of CA the power would go out damn near every time it snowed so my dad finally had enough and got a 4k or 5k generator when i was young. When the power would go out the process was turn off the main breaker that supplies the house from the street and turn off any random breakers for crap that was unnecessary (marked with red dots in the panel). then plug in the generator with a suicide cord to an outlet he installed in the garage (pretty sure it was a 6-50) then fire up the generator and it would power the things like the fridge, freezer, microwave, etc. My dad worked as an electrician for 37 years before retiring so I'm inclined to believe this was perfectly safe to do. Although I'm also inclined to think this is possibly just the way we used to do things and have since changed the standards.

My dad passed a few years ago and my mom moved to a smaller house and now is considering getting a generator to power things when the power goes out. When i visit her every month i do all the random fixes and stuff around the house and if she gets a generator i will have to get it working and make clear directions on how to operate it, just like my dad did back in the day.

I was reading a few things off google and most say not to plug into a random outlet because backfeeding, but if the main is turned off as step one doesn't that eliminate the possibility of backfeeding? I really don't want to have to wire in a new panel for a transfer switch, couldn't i just install an interlock like this or a similar product?

She is looking at some 3k generators so i was thinking i could install a 30A breaker with an interlock and run some 8 AWG to a 5-30 outlet like a few feet from the panel, and use some 8 AWG to make a 20ft extension cable. I could do a shorter extension cord but it would be a shorter run this way than if i ran the wire for the outlet up and over through the attic to closer to the door so the generator can be outside. I know 10 AWG is the standard for these size runs but i figure going one size bigger would be better that way its a smidge beefier than necessary and i wouldn't have to worry about overheating or anything.

Edit: added pic of main panel I noticed there is no main breaker on here like I thought there was. So the main breaker is outside on a panel right next to the meter and that panel doesn't have a cover it's just one of those wires exposed panels with the big cover on it. So I could still kill the main and put a breaker on the main what I'm now gonna call the main sub panel but I don't see any way to install an interlock since if I put the gen breaker outside it would be on the same leg as the incoming feed which is obviously something I can't do.

Answer 1

That only ever worked because of your dad's skill

the procedure was
turn off the main breaker
plug in the generator with a suicide cord
to an outlet
My dad worked as an electrician for 37 years
perfectly safe to do.

No. What your dad did, was replace actual safety with pure skill. ONLY STUDIOUS CARE prevented a dead lineman or family member. If an error had been made, blammo. Average folk can't handle that.

I know you want to think well of your dad, so I suggest taking the viewpoint that this setup was only possible because of your dad's skill. That generation has moved on, and nobody these days possesses the skill or level of care to pull it off. It was never safe and never legal.

From my POV, it looks like "Shoemaker's son".

Also I doubt it was a 6-50 since it doesn't have neutral. It was a 14-50 possibly, but if it had slanted pins on it like Ghostface from SCREAM, that's a NEMA 10 family. Deadly dangerous. But nobody knew that in 1984.

An interlock and a proper inlet eliminates several possible problems:

CORRECT on all of the above. But add two more.

• When the generator is off and the house has returned to utility mode, and the generator is being put away, the person unplugs the suicide cord from the generator end, and the prongs are hot with utility power. Blammo.

• When a family member needs an extension cord for a welder, they find a cord lying around and see a 14-50 plug on it, so they plug it in and start furling out the cord toward the welder. They assumed it had a 14-50 socket on it and never dreamed it would have another 14-50 plug. Blammo.

And that ... is why anytime I make a "weird adapter cord" it is ALWAYS 1 foot long. That way, when someone finds it lying around, they ask "why would someone make a 1 foot extension cord? OH, it's NOT an extension cord, it's something else!" and they take a hard look at the ends. Every actual extension cord in my world has matching plug/socket.

Oh, and one more thing. I don't do suicide cords, not even 1 foot long. I install inlets. Every appliance has an inlet, it's usually just on the end of a cord and called a plug. So if you're gonna violate code why not just install an appliance cord/plug coming out of a junction box? That's an inlet. Use a proper strain relief and it's almost code. Arguably code if you argue 400.7(A)(4).

Obviously yes, you do need an interlock for that, otherwise the prongs would be energized when utility power is on. But interlocks are easy anymore. The Siemens ECSBPK01 and 02 are $30. For main-breaker panels they're a little more, but under $100 for any modern panel.

Your mom CANNOT DO THAT

but if the main is turned off as step one doesn't that eliminate the possibility of backfeeding?

Again, no. I know you love your dad, but science has proven that procedural checklists Do Not Work for anyone else. And your mom is not your dad.

Ask the Marines. In a crisis, people don't rise to their full potential. They sink to the level of their TRAINING. That's why the Marines train so hard. Just look at the performance of the Russian MOD in the past year. Those jackasses, that'll be your mom trying to get the power back on in the cold and wet.

Interlocks also make the procedure much simpler, and remove hazards.

if she gets a generator i will have to get it working and make clear directions on how to operate it, just like my dad did back in the day.

Your senior citizen mom is not your dad at prime of life. Those procedure checklists are fraught with danger. Interlocks aren't.

Doing this right isn't even hard

• √ Want to do it in this panel, not the outdoor panel
• √ Sane cost
• √ Safe and legal, so anybody can help your mom safely
• √ 20-space Siemens panel with 18 spaces used, but 240V breakers that can be made a quadplex to free up 2 spaces.

Easy peasy.

Siemens makes generator interlocks for almost all these panels, in the sub-$100 range. Now all I need to know is if your outdoor main is 200A or 100-125A. We'll be retrofitting a main breaker into this panel if needed, but if it's 100-125A we can get it done with a $30 ECSBPK01 interlock and a couple of branch breakers. A proper inlet of course because you love your mom.

Answer 2

Update:

In order to have a proper interlock, which is safety critical, there needs to be a "main" breaker. Assuming that there is no way to do that at the actual main breaker at the meter, there are two possible options, depending on the specifics of this particular panel. (A picture of the label, possibly on the inside of the door, would help.):

• Main Breaker

Some panels with a "main breaker" spot like this one can be converted to main breaker panels. An advantage is that is abundantly clear to anyone/everyone without any special labeling.

• Back-fed Supply Breaker

Move the feed wires from the lugs to a branch breaker. An advantage is that, depending on what interlocks are available, you may be able to put the supply breaker and generator breaker "anywhere" except that obviously they need to be next to each other. Using a main breaker the generator breaker has to be at the top, which might mean more rearranging of other stuff.

The catch is that the largest branch breaker available may turn out to be smaller than the existing (elsewhere) main breaker. If that's the case then you may not be able to properly power everything in this panel, which would be a problem.

In addition, you only have two spare spaces. You will need those for the generator, so to add a back-fed supply breaker you will have to do even more doubling up of breakers - probably replace the spa double 20 and the double 20 below it with a quad 20 in two pairs, making sure that each pair (inner and outer) has common trip.

An alternative is a panel upgrade, as this panel is quite full. But that is obviously a much larger task.

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Original answer:

All good (interlock, 30A, 10 AWG, etc.) The only thing you need to do differently is to use a 14-30 inlet rather than a 5-30 outlet. (5- is for 120V, 6- for 240V, 14- for combination 240V/120V which is what you need for a generator to power both legs of your panel.) With an inlet you use a standard (i.e., male/female) extension cord rather than building a "suicide" cord. With that last piece in place the only remaining safety issue is location of the generator. The inlet should be on the outside, which makes it a little easier to make sure the generator stays outside. A generator running inside, even "just a little" (e.g., in a garage near the door) is a carbon monoxide poisoning waiting to happen.

With all of that set up properly, the process is basically:

• Turn off main breaker
• Turn off unwanted branch breakers (like your old "red dots")
• Slide interlock
• Plug in generator
• Turn on generator breaker
• Turn on generator

An interlock and a proper inlet eliminates several possible problems:

• Zapping utility crews (interlock)
• Zapping yourself (interlock and inlet - without the interlock, those prongs would be live when the generator is unplugged)
• Zapping yourself (suicide cord for outlet - prongs on the end would be live when the generator is on so if you unplugged it before turning off the generator you would be at high risk of zapping yourself on the prongs)