Emergency Generator

No. if you plan to plug it into a 110V outlet. You'll need to feed both phases if you try and run an AC unit this way.

I'd just say NO!

My intent is to provide the minimal amount of power to keep a refrigerator running and some lighting. Most of my lighting now is LED, so I'm not looking to power the entire house. In practice, all my 220 V circuits would be un-powered and disconnected; looking at a generator of about 5000 watts.

Oh, I thought, "emergency use for lighting and refrigeration" meant air conditioning , not a refrigerator.

Backfeeding with a Generator is Dangerous | Norwall PowerSystems ...

"Energizing the utility lines in this fashion is dangerous and illegal. Workers attempting to restore power to the neighborhood may unexpectedly encounter high voltage on the utility lines and suffer a fatal shock."

It may be illegal in many localities.

Just because you say it can be done without any danger is inviting someone, with little or no experience, to try it.

Not a wise thing to do.

As I said, some uncaring people still make suicide cables.

Back in the 90s we had some severe storms go through the area and had a lot of folks without power for several days. This was before the Y2K scare so generators still weren't that common. As in most rural areas, everyone got together to help each other out. A few people who had generators made 230v "suicide cables" so they could just plug into the stove or dryer outlet. The generator and cable would get passed from house to house. Each homeowner could run it long enough to cool their refrigerators, freezers, and power their well for a while to get what water they needed. Unfortunately a young man who either didn't understand what he was doing or just wasn't thinking crawled between the washer and dryer and unplugged the cord from the dryer outlet before shutting down the generator and handed the cord with the energized exposed end to his daughter (about 10 years old). She was severely burned and ended up losing the pointer finger on her right hand.

I know both families and can tell you the guy who made the cable still feels terrible about it. He had good intentions and was just trying to help his neighbors but it didn't turn out too well.

I would recommend doing it the correct way. It's too easy for accidents to happen.

It IS ILLEGAL and very DANGEROUS anywhere in the USA. If you don't understand why do not even think of doing this!

I'm not the one who is asking. Why was your comment directed to me when, if you had read any of my posts you would have seen these comments:

#1 "No. if you plan to plug it into a 110V outlet. You'll need to feed both phases if you try and run an AC unit this way. I'd just say NO!"

#24

Backfeeding with a Generator is Dangerous | Norwall PowerSystems ...

"Energizing the utility lines in this fashion is dangerous and illegal. Workers attempting to restore power to the neighborhood may unexpectedly encounter high voltage on the utility lines and suffer a fatal shock."

It may be illegal in many localities.

Just because you say it can be done without any danger is inviting someone, with little or no experience, to try it.

Not a wise thing to do."

#36

"You have gotten some really good advice, and some really bad advice here.

Let me be the first ^{_{(I think)}} to say if you want to do this, HIRE A PROFESSIONAL, LICENSED ELECTRICIAN" !!!!!

You should read the ORIGINAL POST from ronseto.

Use of the "widowmaker" is definitely illegal in most jurisdictions. The main reason is that it is still possible and likely that someone on the grid will leave their mains breakers closed and be energizing the line out to the pole, creating an extra hazard for repair linesmen.

Most places will require a transfer switch to force the mains to be connected either to the grid or to the generator.

It does raise a question I'm not familiar with: What is the hookup requirement if you have solar panels and an inverter where your system sells electricity back to the grid? Some solar systems are intended to feed both your house and the grid.

This is one of those safety questions that is dangerous to answer. I would not be surprised to find out that some people have done this without a problem. I can just as easily see a generator being roasted, a refrigerator roasted, a house burned down or even people dead from electrocution or asphyxiation.

In short, if you have to ask don't do it. If you don't have to ask, build a proper disconnect switch and get it approved by the AHJ for your location.

Moreover, you couldn't run a very large collection of loads.

Roughly it's, 5 AMPS per ton @ 240 V. Just for AC.

Air conditioning and heat pump loads on a generator - Generator Joe

Tapping into several outlets on separate breakers with extension cord might be an interesting science project.

Could you? as in possible....yes Should you? no it's not a safe solution....

Not true.

Not true in what way? Not true that either one of the circuit breakers will trip?

Without having the actual capacities of either the house circuit breaker or the actual generator being used it's all speculation based on all theoretical worst case what-if scenario conjecture. A thought indoctrination concept I do not subscribe to.

Suppose the genset (say 4kW) has a 50A breaker, but a group of outlets is on the same 20A house breaker with 12AWG wiring everywhere in the circuit. Then it would be possible to run 48A of load on the genset with all 48A going into a 20AWG wire.

I think you're grasping at straws to come up with what-if scenarios to justify your belief systems.

How would a 4000 watt generator have a 50 amp breaker in a factory made design?

At 120 VAC 4000 watts is 33.3 amps and such a unit would likely have no larger than a 30 amp circuit protection system.

That is assuming it was only capable of 120 VAC output only which if so would have a standard 120 VAC 3 prong 30 amp twist lock and one 20 amp protected single or duplex or two 15 amp protected single or duplex outlet sets.

If it was 120240 VAc capable it would likely only have two 15 amp single or duplex outlet sets and one 120/240 VAC 15 amp 4 line twist lock since the codes for what type of outlets on any size of portable genset are fixed and not open to oversizing simply to protect the genset from deliberate or accidental overload.

No matter how you slice it a 4000 watt portable genset would not have any viable stock factory made connection capable of more than 30 amps.

As for who does what on the house side, as I have stated before, it's unrealistic to think that anyone is going to deliberately start plugging everything they can find into a single back fed circuit just to see how much power they can pull off of it.

Especially if they are only usings simple double ended 120 VAC 15 amp cheater cord to back feed things. They would be stuck with the either 15 or 20 amp single line output limit of the gensets outlet sets.

To deliberately overload things beyond that just not something one of a rational mind does in a emergency power situation which leaves the only way to get to that point being irrational actions which in themselves negates all bets on what someone like that will do regardless of safety systems on anything anywhere.

Same with using a grossly undersized 20 AWG cord for a higher powered load as you mention for whatever reason. It's a non issue given if used incorrectly on any circuit even of a 15 amp rating it would be overloaded to the point of likely starting on fire after minimal use regardless of whether it was back feeding a house or being used on normal conditions.

why/how do you figure any of that could happen and how exactly would I be responsible for any of it? You do have some working knowledge of internet information sharing laws,right?

"Because someone said so" or "You found it online" does not overrule ones own personal responsibility for working within their own personal limits of knowledge and experience nor does it pass of responsibility for anything that may happen to them either.

As for the guy who got burned, what exactly does him and his boss failing to follow proper procedures on a jobsite have to do with anything here whatsoever?

Why was the guy in the pit not using bonding straps on the lines while in the pit?

And, more importantly, how exactly does a supervisor, or anyone related to that service job, come to the conclusion that they can remove safety protocol equipment and re energize a line without having confirmed though personal and or multiple others literal eyes-on confirmations of all service point work being complete and agreements that it was safe to do so?

When I learned HV service and safety procedures no one ever took off lockout/tag out gear and energized anything without having multiple eyes on confirmations that absolutely everyone and everything was clear of all points on a line that had any work done to them.

Same with the reverse of starting work a on a line. Until multiple confirmations of it having been locked out hard plus bonded to a dead short condition at at least 1 or more points were done nobody touched anything anywhere.

People over a thousand miles away from any hurricane damage should not give advice on how to reconnect the power grid after a hurricane.

Your solipsism is only annoying when lives are not risked. Please stop.

It is EXTREMELY DANGEROUS from a number of points. NEVER do this. Invest in an approved changeover switch and hook-up. If you don't believe me call up your power company and ask them.

A set up as you are suggesting has a nickname over here “widow makers”

It would be far safer to use something like these https://www.mkelectric.com/en-gb/Products/WD/IngressProtected/commando2013/Documents/MKCommando2013RangeUpdateBrochure.pdf

Unlikely given any common portable generator is going to have the same types of outlets as any home has and the same rating of fuses or circuit breakers as well.

On top of that which ever outlet is working as the feedback point for the whole house still has its own fuse or circuit breaker as well that will be dictating the limit of whatever the house can draw through it.

So given that even if he was using the higher powered 30 - 50 amp power feed off of a larger generator and back feeding the whole house through a 15 amp line the whole house is still limited to what that 15 amp lines fuse or circuit breaker can handle.

I've never seen a standard residential service fuse or circuit breaker that was AC rated that cared which way the power went though it.

And as I said before the generator more than likely has it's own protection devices as well thus in my books making all the safety concerns non issues in practical realistic conditions.

I don't know what common practice is your side of the pond - in the UK, domestic outlets are usually rated at 13A, but frequently unfused (the appliance fuse is in the plug, on the basis that each appliance can be fused appropriately).

American based system run everything through a primary distribution panel where every circuit coming out of it is protected by either a 15 or 20 amp breaker unless it's a larger dedicated feed to a larger power user like a central air unit, water heater, stove or electric heat system.

Using a "suicide cable" (a piece of flex with a plug on both ends) in such an instance, will limit the power that is able to be drawn to 13A, the rating of the fuse in each plug, or a little over 3kW in UK mains terms.

• It is vitally important that, in this hack, the house is disconnected from the incoming mains before connecting the generator, and that the generator is disconnected before re-energising the house mains supply.
• It is vitally important that, in this hack, no-one unplugs the house end of the suicide cable while the generator is running, for that is the reason for the name of the cable, in that 230V is presented across the bare pins of said plug.

It is safer to install a generator inlet connection that feeds the distribution board via a suitably-rated change-over switch at the distribution board. That way there is no risk of back-feeding the mains supply to a worker in the field trying to restore it, no risk of live pins being presented to anyone in the home, and the power available can readily exceed that limited by the 13A fuse in a domestic plug up to the limiting rating of the generator and its protection circuitry. Such an installation needs ideally to be carried out by a qualified Electrician in accordance with BS7671 and the completed installation tested and recorded as safe so as to ensure continuation of fire cover by the building's insurance company; Loss Adjusters are always looking for reasons to adjust the losses downwards - that is their job!

The general principal of your post is well taken, but some of your assertions don't necessarily apply to a resident of Vancleave, Ms about 30 miles inland from Biloxi and the coast.

Where?

ronseto's stated location.

Never heard of it.

Now don't go all American on us . Just because you haven't heard of a place doesn't mean it doesn't exist!

Come to think of it, I've always been curious where 7 chains down the line from Dodman's Lane level crossing is too.

But whatever set of outlets may be on the circuit could then have a collective load larger than the wire or the normal breaker can handle, but still less than the generator breaker. Possible fire waiting to happen.

How so?

In an emergency power only situation where you are running off of a well known to be limited power source the typical thought process is to cut all non essential power usage down to as little as possible, not add as much as you can figure out how to do to whatever random points in the house that will take it.

Especially so when one is using a portable genset in a non dedicated power backfeed feed application of questionable capacity to begin with.

theoretically, yes I agree, it could be possible to overload a circuit but realistically the rational mindset in such an emergency situation where you have nothing beyond what that one backfeed line can carry to work with is in play one doesn't go about deliberately trying to push it or any of the systems limits.

Consider this situation. roseto buys a 5500 watt (he said about 5kw) generator and connects to the 240 volt outlet. Since generator is 5.5kw it is probably rated at least 6000 volt amp. Protection (probably circuit breaker) is (125% of load) 30 amp each side. He connects his heavy (looks heavy because of much insulation but is #16 wire) extension to a 15 amp protected (#14 wire) circuit. He forgot he also had a 1400 watt heater plugged into a far off receptacle on this circuit. Finding the outlet where refrigerator is plugged in is dead he runs an extension from it to an outlet on same circuit. He now has an 18 amp (12 amp heater+6 amp refrigerator) load on his #16 cord with nothing going through 15 amp panel breaker. He can still add other loads in an attempt to catch the cord on fire or the house wiring between receptacles. These are easy thing to happen in a power outage situation.

I usually much appreciate and tend to agree with your responses but I disagree with this one.

Worst case scenario theory and and occurrence of fact in real life are two different things. That's what i am trying to point out.

Can something bad happen? Yes of course. But realistically what are the odds of it happening by accident and what are the odds of that happening while being aware of the less than normal and typical situation at hand while doing it?

If they did every time you take a shower you should slip and fall and die.

Every time you get in a vehicle you should be in an accident and die.

Every time you eat food you should get severe food poisoning and die.

Every time you go online you should get a computer virus then have your computer burst into flames and kill you.

Every time you turn on your stove it should either leak gas and explode or short out and kill you.

Everytime you sneeze you should rupture a blood vessel in your brain and die.

Every time you go outside you should be attacked by wild animals and die.

Every time there is a thunderstorm you should be struck by lighting and die.

Every Time you take a pill it should be the wrong one and kill you.

All Of these things have happened and do happen to multiple people every year and some even every day yet somehow the majority of us are still here and still do those things every day without concern because of what-if could happen.

Just because someone can imagine some ideal storm conditions to make something theoretically possible does not make all normal actions equally dangerous and bad and to end with the imagined worst case perfect storm scenario results.

It's the very basics of statistical probability and weighting the rational concern against the realistic likelihood of whatever it is actually happening. For me anyting that scores a less than 1 in a 100 chance of happening is a non issue and pretty much every made up concern here are things I would say fall well beyond one in a million odds of ever becoming a reality.

That's my point. Someone does not have to have perfect and deep understandings of a situation to be able grasp the concept of being careful. Especially so in a emergency situation where it should be apparent that they have a very limited resources of working capacity in play where special considerations to the limits of what they do have to work with are necessary.

I don't believe everyone in the world is stupid and incapable of basic rational self preservation thought and thusly I feel zero need to concern myself with what-if's based on them not living up to my expectations let alone me having to protect them from themselves.

I agree that we sometimes go to absurd lengths to try and prevent highly improbable things from happening. I think there are times when risks are worth taking but how difficult is it really to just run a cord to each appliance you want to use?

To be honest I think it would take more effort to make a "suicide cord" than to just run a cord to each appliance.

This is what I was thinking, then the other potential issues are nonexistent. When I replaced a service panel, it was suggested by an electrical inspector to run a piece of Romex exposed on the ground (luckily it wasn't a real long distance away) from another service panel which technically wasn't according to code but it was only a temporary situation. A few important appliances were then plugged into receptacles on the end of the Romex cable. Sometimes things aren't done exactly to code if it's just a temporary thing and it's not really dangerous.

" if it's just a temporary thing and it's not really dangerous."

The good news for you is that you can only die once.

Hopefully using that "temporary thing and it's not really dangerous" the one time it is really dangerous will only kill you and not some innocent bystanders.

What I mentioned was not dangerous---otherwise the electrical inspector wouldn't have suggested it.

I have been an inspector for over 13 years and never would have given you that advice. The guy who did did not what he was doing "romex" is not rated for temporary use on the ground.

I understand what you said, and what you did per the inspector, which is not what the OP is suggesting he do.

What he proposes has the very real potential of back feeding into power lines which go into the grid.

Regardless of the declarations of some members here, this is still illegal and as I have already said should ONLY be carried out by a licensed electrician per NFPA 70e, and local codes.

What if he is like me and lives in an area where local codes still allow the homeowner to do their own service work? Then what?

I've spent the last few days trenching in new water lines for a family member and where we live none of it needs to be inspected afterward. Soon I will be installing a 200 amp service to a new outbuilding some 400 feet away from the primary utility service and that too will not need inspecting where I live.

In fact he only caveat to that is I have to have the local utility company change out the old 1950's primary service meter box with a new one so that I have room to add the new line 4/0 sets. Also, BTW, that same utility company will also sell me the 400 feet of 4/0 line I need to do the job too.

"What if he is like me"?

I'd say the odds of that are 10,000 to one that there is another individual out there like you.

So far, ronsetto has not indicate his level of competence in this area, maybe he's willing to do it, we don't know either way.

Exactly, Temporary allowances for emergency and or special case conditions do exist.

I've seen and even used them countless times myself on the job.

'A' is not up to code but 'B' is/would be. However 'B' can not be implemented without relying on 'A' to get 'B' is set up and in service so that it can eventually take over and replace 'A'.

As long as the limits and potential issues with 'A' are taken into consideration while 'B' is being setup use of 'A' is allowable for a time.

That's where the personal call on doing anything come into play.

For someone who is not up to the task of making a custom cheater cord to back feed their home that what extension cords are for. However for those who understand the basic working principles of doing a power backfeed it's a trivial concern.

That's why I put an effort into pointing out the realistic likelihoods of what it takes to actually make something go dangerously wrong. 'Can go wrong' is not an automatic proof that 'It will go wrong' rather like anecdotal evidence is not proof of a regular high concern occurrence issue. If it was we humans would be extinct by now.

Sounds like you are going to do this no matter how many people advise against it. Under ideal conditions, sure it will work BUT there are so many extremely dangerous scenarios that could happen........Just do not do it this way please for your safety and others not to mention possible lawsuits against you for causing injury, death or property damage. Please just don't do it this way.

I'm not the person doing it plus you can't sue a person for advice/instruction or whatever they post on the internet for good or bad.

Read up on internet civil/personal liability laws and the various others that relate to such things.

I can post that you can put a pistol in your mouth and pull the trigger and it won't kill you and I am not liable for whatever happens from you doing it simply because if you are too so stupid you can't figure out what is bad advice for you to follow, given your limited knowledge and or skillsets at the time, it's your own damn fault for having done whatever it was someone else said could be done legal or otherwise.

Murphy's law states; If it can go wrong,it will go wrong!

So why take a chance?

Because some of us don't live in fear of every possible what-if that can be conjured from anecdotal associations to others mishaps or paranoid folklore.

Today I put gasoline in a tractor that came from a above ground ungrounded metal tank which could have generated a spark when the nozzle contacted the metal tractor fuel tank fitting yet, obviously, I am here now and not in a burn ward because "murphy's law" should have dictated that it blew up in my face since "if it can go wrong it will go wrong" as you say.

I get it. You don't care about anyone's life but your own. You just troll for misery to all.

If education into reality and representation of facts brings misery to some I have zero issues with it. It's misery I think a lot more need to welcome into their lives.

Besides, I'm not the one trying to self justify nanny state mentalities with wild what-if based theories and conjecture derived largely from anecdotal rather than statistically derived references.

People need to see and learn that not everything in life is as terrible/bad/dangerous/whatever as some try to play it out to be for whatever self imposed reasonings they have for or against it.

I mean, if someone, or a number of people, told you that they all knew someone who died in a vehicle accident and that thusly everyone who travels in a vehicle will die if the next time they get in one (based entirely on wild made up what-if/perfect storm imagined scenarios), what would you say?

'Yes,I agree. No one should ever ride in a vehicle ever again because they're too dangerous and XYZ could happen at any second thus killing everyone involved.'

Or, BS. Personal experience plus statistical data says otherwise so get in your vehicle and drive smart and the odds are you will be just fine.

"On top of that which ever outlet is working as the feedback point for the whole house still has its own fuse or circuit breaker as well that will be dictating the limit of whatever the house can draw through it."

Not true. Devices plugged into the same circuit as the generator will not be protected by the breaker or fuse at the panel. This is dangerous and against code. If the house burns down, the insurance probably will not pay.

The open window or door that the cord is coming in will let the heat (or the cold) out, reducing the efficiency of the process. It might also let in a mouse, wasp, or mosquito with a disease. Get a legal hookup, as others have said, and save yourself a lot of unnecessary problems.

"Not true. Devices plugged into the same circuit as the generator will not be protected by the breaker or fuse at the panel."

No, but it is still protected by the fuse or breaker on the generator, as I have stated in other replies. To which, given the typical person who is not electrically savvy does not have a special high current 10 gauge extension cord that plugs into one of the 3 or 4 prong 20 - 30 amp higher current outputs that most 3+ KW portable generators have, they will more than likely be feeding off of the normal 15 - 20 amp socket set thusly still limiting their ultimate power draw to within the working limits of what any household electrical circuit would and could have.

As I have stated and alluded to multiple times now, sure it not impossible to overload a backfed circuit to the point of starting a fire but to do so would take a willful and some what knowledgeable effort to make the condition possible.

Efforts, that if a person understood things well enough to try, they would also more than likely be aware of the dangers and truly make the effort to set up the backfeed to use a more fitting high capacity connection point into the house electrical system from, such as a electric stove, dryer or garage based dedicated power point.

Conductors do not need to be sized for starting current; instead for FLC x 1.25 (and maybe some voltage drop considerations).

Yep. In my books a 6 - 8 amp load could be ran off of a 100 foot 14 ga extension cord without issue including allowances for 4x startup current draw.

A common 100 foot 14ga cord has a resistance of ~ .5 ohms. Given that the refrigerator compressor even at a high 4X start up draw and 8 amp running current ( highly inefficient refrigerator to say the least given my large 1970's built one draws 3.5~ amps at best) would at worst see a ~ 16 volt drop from the assumed to beo correctly functioning generator that is putting out 120 VAC. 16 volt off of 120 VAC would be a ~ 13% loss.

Which given by standard design code any properly made appliance should work within +- 10 - 15% of it nominal input voltage rating to which most every appliance that runs of of a 120 VAC line is actually rated at a 115 VAC input. 10% loss off of a 115 VAC line is ~ 103.5 volts.

120 VAC - 16 is 104 VAC or close enough in even the worst case startup load scenario using a grossly inefficient refrigerator and not assuming the generator is not like most cheaper one that at no load tends to run 5 - 10% over voltage and frequency at no or light loads.

Your house main is 220 volts with two 110 sides and a common ground. If you flip off the main breaker by the meter, then you might run a cord from the generafor to a house outlet after flipping off the oven and central air breakers, but only half your house outlets might then see 110. If you connent another cord from the other side of the generator to the unpowered outlet, you will trip a generator gpf because of the common ground. The solution is to get a 4 prong 220 plug that has a ground, two 110 prongs and an earth ground and adapt it to two substantial 20 amp female connectors. The 220 volt outlet on the generator will not have gpf protection and trip because of the common ground making it impossible to assue current on the 110 sides and their grounds are exactly equal. So best to add a 220 outlet to your outside panel, and make two adapter plugs to use your heavy 110 extention cords. One adapter takes a 220 male plug to two 110v female plugs, the other takes a 220v male plug to two male plugs. Flip off the main, plug in your adapters and both sides of house power are live.

Works fine, not to say this is legal since an idiot could flip on the main with generators going, killing power workers, but you are not an idiot, and a 220 female plug mounted by conduit and box under your main breaker panel outside is legal and better than running a cord to an outlet using a cord with two male plugs. At 10 bucks per good hubble, 60 bucks for the two adapters and 80 to 140 bucks per extention cord. you will hookup in 2 minutes for the next hurricane.

The guy who suggests a real power transfer switch is giving you the code legal approach. My solution is not the legal way because of the possibility of flippjng on the main breaker with the generator plugged in. But it will work fine, as would one male to male cheater cord to plug into one outlet. Beware of your 20 amp #12 outlets and #14 wire 15 amp outlets - 300 buck generators put out only 13 amps a side, but a big generator means beware of wire and outlet ratings. use led bulbs.

"Works fine, not to say this is legal since an idiot could flip on the main with generators going, killing power workers,"

How would it kill line workers? Are you the least bit aware of what a lien workers safety procedures are for wrong downed lines?

One of my first jobs was a student co op job working as an apprentice electrician of sorts at a coal mine. Even as a 19 year old peon I had full training on how to work with the mines HV distribution systems including 4160, 6600, 7200 and 23,500 VAC systems.

Rule #1 of working on anything in those HV systems was full isolation plus full confirmed earth bonding of every conductor at both ends plus backup bonding, within literal line of site, at the point of work to be done if said work was not being done at one end or the other off a feeder line set.

The same rules that every line man of today uses just to make damn sure what they are working on can never be energized to a potential high enough to kill someone whether it be by accident al back feed or any other accidental mishap.

That's why I have such a peeve of the 'Linemen will get killed' if a backfeed occurs BS. It's simply not a issue with properly done modern day repair operations that follow the lineman's work and safety code.

Yes, however the reality is is that there is a real chance in a wide spread outage situation that many people other than trained utility workers may come into contact with a grid energized by some idiot managing to back feed energy to it. No matter how you slice and dice or justify this idea, it is wrong. Codes are written for valid reasons.

Anyone stupid enough to mess with downed lines gets what they deserve. I have very little sympathy for careless or stupid people who can't take responsibility for their own safety. Especially in a situation that was so bad that major structural damage has happened to key utility systems.

Then there's the reality that it is extremely unlikely that anyone who is running on a genset has the output capacity to energize any downed line anywhere anyway. If the HV lines are down they are in contact with the ground plus more than likely lying across each other in a shorted condition that would put a load on any small genset that is way beyond its capacity to support.

Have you ever tried to energize a multi 10's of KVA utility grade transformer with a portable genset from its 120 VAC 15 or 20 amp single feed circuit? I have. It does not work so well simply due to the naturally low inductive impedance which produces a high no load inductive current without anything being connected to its secondary.

High enough that a 120 VAC 15 amp circuit all by itself may or may not even carry it and even if it did the odds are that HV utility side output would still be feeding to other transformers compounding the loading issue to well beyond its working capacity, assuming none of the downed lines are in contact with the ground or in a shorted out connection to begin with.

Simply put, under realistic emergency conditions with downed lines in play a common sub 10's of KW portable genset does not have the realistic power to back feed any utility systems long enough to cause a realistic problem. It's just too small. Like trying to jump start vehicle off a 9 volt battery too small.

Where in the above post did I mention "downed lines".

You didn't directly but when you say,

"many people other than trained utility workers may come into contact with a grid energized by some idiot "

to me that pretty much has to include anyone who is a civilian and not a trained lineman given no one should be able to come in contact with a HV line unless it's either a overhead line on the ground or pulled down by a tree/fallen object or they are up in a boom truck.

Beyond that, the simple concept that from an early age all people who do not work in the electrical field are generally pretty well psychologically conditioned to not go anywhere near any downed power lines of any form thusly for some to come in contact with them while they are still powered up requires some degree of either extremely circumstantial conditions or outright idiocy on their part.

Then there still the fact that if such a line got pulled down that far how likely is it that whoever is backfeeding has a large enough generator to even keep it powered up both while whatever event and object pulled it down plus afterwards plus while sustaining whatever purposeful loads they already have on it?

a few KW doesn't go very far or power much of a load on a 4160 or 7200 volt line that most residential type locations would be powered from. Even less so on a 120/240 LV side feed that's split between two or more houses.

How many linemen do you see in this picture?

I suspect many distribution transformers have HV wires dangling in this water. If one transformer gets back fed from a suicide cable...

How long do you suppose a portable genset can hold up a dead utility service feeding dozens of dead loads or even one partially shorted line plus whatever load it is supposed to be powering?

Methinks about half a second.

You do know how to do basic math and apply it to reality, right?

Okay hilary. You've already written your lies and excuses for reality not being what you want it to be book, so isn't that enough yet?

Its obvious you can't actually find factual faults with what I say so once again you take the petty coward's path and try to attack me for who I am personally or with topically irrelevant drivel in hopes of derailing me, only to once again, fail at it. (I know your game, remember?)

Either way, way to live up to those typical worn out low wit hypocritical liberal standards and false flagging and false virtue signalling, plus general parroting tactics of things you couldn't initially come up with yourself, so many here have come to know you for!

A+ for your predictable consistency!

Hear, Hear!!

The main problem would be if the genset backfeeds into an open circuit, which is entirely possible, and dangerous.

Ordinarily I appreciate your hands-on, can-do style; but your posts in this thread are among the most spectacularly incompetent I have ever seen.

What exactly would be dangerous about backfeeding an open circuit? It would be like backfeeding an unused extension cord. Theres no place for the power to go and thusly no real danger to anyone anywhere any more than when the line is being powered in a normal working condition.

No modern day lineman is going to grab onto a line (down or otherwise) until it's been confirmed shutdown and electrically bonded into a short circuit and any unassuming civilian with any sort of functioning brain and self preservation instincts certainly isn't going to mess with a dones power line of any shape or form.

As far as my incompetence, I am not the one trying to make a point using extremely improbable what-ifs and perfect storm scenarios that by even the most rudimentary statistical analysis would show are extremely improbable situations that require a multitude of near laws of physics breaking conditions to even work given the extremely limited power outputs that would be associated with any common sized portable genset any typical electrically unskilled civilian would own.

If you think my being able to see and rationalize that based on simple rationalized plausible logic and familiarity of they key devices and systems in play, that most anyone can confirm though a few properly done internet searches, is a sign of incompetence what exactly does that say aobut everyone else using absurd reasoning against me and it?

The scenarios I have suggested are not "extremely improbable"; now you are just flat-out lying.

In what way am I lying? You provided zero plausible or credible counter evidence to anything.

You not liking my views and rational to how I can support them with solid plausible technical fact and can easily disprove the overall validity of yours does not make me the or a liar in any way.

A number of years ago during a storm my neighbor, a farmer, had an emergency generator with a home brew hookup and knocked a lineman off a pole about a mile away from back feeding. It happens and it can result in death! Take some advice and install the proper and safe hookup.

One wonders why that lineman did not short the line before working on it.

If you are considering a gen set as power back up, I'm guessing that you get power cuts as a way of life, why else would you consider a stand-by gen set?

That being the case, why not do it properly and install a changeover switch on the main incoming supply so you can change from main power to gen set.
That change over switch switch will isolate the main incoming from the gen set, so you don't feed power back up the line, and then you can supply your house with the power it needs.

However before you go down that road, you have to calculate the full load of the house and ensure the gen set can handle the loading.
Or if your gen set is only sufficient to supply a limited Kva, then you can sub-divide your load, using two distributions panels. The second distribution panel is for the essentials (local regulations & rules apply). So the changeover switch from main to gen set lets the generator supply only the essentials that you require.

As for the question, "How do I know when the mains power is back on?".. you install a small indicator light on the mains incoming side.

With this redneck idea, (no offense intended). Can you be sure that your double pole main breakers open and not one still closed?

Last time I heard, transformers work in either direction, step-down or step-up.

Save your self the legal heartaches and do it to code, it will be cheaper in the long run than a manslaughter charge or an arson rap!

You have gotten some really good advice, and some really bad advice here.

Let me be the first ^{_{(I think)}} to say if you want to do this, HIRE A PROFESSIONAL, LICENSED ELECTRICIAN !!!!!

Get a proffesional to seperate the circuits you want to back up on your mains board and feed those with an plug that will go into a socket that are fed from the mains feed. With a power failure remove the plug from the now dead socket and plug it into your generator extension. Every thing stays connected legal and the separated circuits are only connected to your generator life and neutral and earthing system and do not get mixed up with the power utility system. When the power return, unplug the generator and restore mains to the isolated circuits by putting the plug back into the mains fed socket. Your whole instalation is legaly back onto the Power Utility system.

That's basically the same as my boat system. When moored up and with a 230vac shoreline power supply is available it connects to our boat and terminates in a twin 13amp socket outlet.

When cruising, or moored without a power supply, we have an inverter running off the 12vdc in-board boat batteries, that also terminates in a twin 13amp socket outlet.

The boat 13amp socket distribution systems is fed a by a single 13amp plug on a flexible power cable that plugs into the appropriate socket.

The inverter is also a battery charger that plugs into the twin 13a socket of the shoreline power supply.

As a refinement, we have timer sockets to control the dehumidifier during the cold night periods, and to limit the time batteries are on charge.

Works a treat!

Doing it any way other than the proper way is fraught with danger, and any money you save will easily be exceeded by the medical/legal bills that you will have to pay should something go wrong (and your insurance won't pay a dime for any claim if there's a fire or death).

As a practical matter, is this something that you would trust your kids or wife to do correctly if you're not there when the power goes out??

This is exactly the point. There are simple, safe kits available for most panels. It doesn't take much to do it right.

It should also have some Under Voltage Release coils to ensure that you will be obtaining the appropriate voltage levels!

I agree. There is the right way and the mickey mouse way. I will take the right way.

That is the best news I've heard on this thread.

That's the best way to go! Be safe and keep your feet dry