Backfeeding with a portable generator - REAL safety concerns???

So what if the lineman had tested the line and found it to be dead and then started work, our cheapskate fires the gen set up & forgets to isolate from the mains and subsequently fries the lineman who thought he was working on a dead line?

Great, you're hoping I die for asking questions. Nice guy.

I didn't say I was going to do it. I said I've seen it done and asked for intelligent FACTS about the subject.

When was I glib?

Point well taken. I think I'll opt for a switch. Or simply extension cords, splitting my boiler-pump/thermnostat feed with make and female plugs, then simply unplugging the furnace completely from the (house) supply and plugging it into an extension cord. Thanks for one of the very few intelligent answers.

I don't have visitors up here, but that's a valid point.

Now, _THAT'S_ what I am looking for: an intelligent, informed answer. So my plan is _OUT OF THE QUESTION_ then. If there's _ANY_ chance of the main breaker failing -- and letting power slip by -- then I WILL _NOT_ take that risk. The lightning issue is also something I han't considered. Remote possibility as it is, it _IS_ a risk, and I'm NOT willing to take ANY risks. Thank You!

PS: You said breakers can go bad and stay open. Did you mean closed (leting power flow through it)? Also, am I to understand that transfer switches never experience this? Isn't it just a three-position breaker? Or is it engineered differenty? Heavier duty? Better quality control?

Thanks Again for your thoughtful answer. Oh yeah - Yes, NiMo is my power company (Or whatever their new name is now). Friday

But of course. Working long hours in terrible weather, they deserve a good meal and warm hotel room. I can't fault them for that.

As I suspected. A transfer switch isn't necessarily any safer than a standard main breaker EXCEPT, as pointed out by many others - to prevent "human error." Please tell me more about the "fourth ground" procedure you mentioned. I HAVE decided to do it the correct way.

Thanks Aga "... points of protection must have a "visible break" so neither enclosed circuit breakers nor transfer switches are considered safe for personnel protection purposes"

What is meant by a "points of protection"? And are you indeed saying that transfer switches are no safer (mechanically) than a standard-issue main breaker in a home panel box?

I that were the case, I wouldn't have bothered asking. I didn't ask anyone to "change my mind." I didn't even say I was going to _DO_ anything. I asked questions.

Thanks for nothing.

Now that's an answer. Thanks

Properly designed transfer switches are usually interlocked both electrically and mechanically. I have seen numerous transfer switch failures, but none where the utility and alternate power sources were inadvertently connected, with one exception where someone had modified the transfer switch for some unfathomable reason.

Louis--

residential curcuit breakers are basicly switches that can turn themselves off once the curent through them reaches a trip point. the failure modes therfore are basicly the same as for switches (with the addition that sometimes old breakers trip sooner then they should) have you ever seen and old wall switch the wouldent shut off? its not as common as the other failure mode where it wont turn on but i can show you an example right now.

one could hope that breakers were made significantly better then common wall switches. i have had a few apart (just to see how they are made) but i certinly cant speak for all the brands that are out there.

to try to answer you question as best i can i will say yes i believe it is possible for a breaker to short in such a way that it will conduct even if the lever is in the off position especially if lightning is involved. i would also say they the likelihood is pretty small. i would also say that it would be likely that if it failed due to lightning or surge there would be some external evidence like molten plastic, burning smell, and/or "gritty" operation of the switch. the problem is no one can predict what will happen only what might happen or can happen or has happened in the past. when it comes to electrical stuff or mechanical stuff some of us old guys were taught Murphy's Laws at an early age. they seemed funny at first, a rather dark, pessimistic outlook. but as time goes by we come to realize that the "Laws" are the one constant in an ever changing existence.

my favorite corollary: Murphy was an optimist

Also, am I to understand that transfer

i have several (transfer switches) at this point under my care three are 3 phase automatic. they are big, expensive, and use contactors (large relays) when i open one of the older ones i am sometimes greeted by a snake. how the snake has kept from being fried by 208 i don't really know. he slithers down the conduit until i close the cover and go away.

one other is a manual 3 phase. it is very old. i believe it to date from

i hear ya. last 2 winters winters would make an eskimo shiver

its called a "power distro" (short for power distributor). it looks and works very much like your main house panel.

You missed the 'install grounds'. That means the lineman puts a cable about the size of a heavy-duty car-battery jumper cable across each phase and to ground/tower/whatever. *Then* they start work. Lineman don't consider the line dead until they have the grounding cables installed. If the line can be fed from either end, then two grounding sets are installed. Lineman works *between* the two grounding sets.

Don't know if *all* utilities require this, but many do consider it a 'fire-able' offense to work without them.

Some smuck comes along with a gen-set and forgets to open the main, his generator will just feed the grounding cable (dead-short) and burn-out/trip his generator.

Mind you, if the grounding cable slips, or sparks a bit, the lineman is going to jump down, find the SOB and cut their service drop. Then it will be a while before customer gets restored.

daestrom

| Great, you're hoping I die for asking questions. | Nice guy. | | I didn't say I was going to do it. I said I've seen it done and asked | for intelligent FACTS about the subject.

Use a listed transfer switch. Period. They come in manual and automatic. There are even some double-throw light switches for transferring single loads. Be sure the switch is rated for "load break" or "load transfer". One rated as "isolating" is insufficient unless you be sure you shutdown the generator before transferring back to the grid.

Don't even think of depending on doing the right procedures. There can be a time when someone else could try to switch things because you are not around. You may be smart enough to be sure you don't get hurt, but can you be sure anyone else who might ever have access is?

The truth is that no professional will risk their reputation by advising you to go ahead with your plan.

You've got a pretty good idea of what the risks are. You want to chance it, you're on your own.

P.S. While most professionals reading this newsgroup are bound by ethics not to advise you to pursue your plan, there are some that are obliged to report to the proper authorities should they discover the existence of such a situation. Or they might BE the proper authorities.

Hospitals and other critical facilities do exactly this. They use Orange colored outlets for critical power sources, if the entire facility is not on a huge genset.

Gunner

"At the core of liberalism is the spoiled child - miserable, as all spoiled children are, unsatisfied, demanding, ill-disciplined, despotic and useless. Liberalism is a philosphy of sniveling brats." -- P.J. O'Rourke

We understand that you were well meaning. But after the 4-5 comment from others that to do as you wish, it became apparent that your wishes to do this the easy way..ala do it yourself cardiac bypass, were overruling common sense and life saving methods.

Sometimes you can do things cheap and easy, sometimes either cheap or easy, but not both..and other times..neither.

Gunner

"At the core of liberalism is the spoiled child - miserable, as all spoiled children are, unsatisfied, demanding, ill-disciplined, despotic and useless. Liberalism is a philosphy of sniveling brats." -- P.J. O'Rourke

daestrom,

Actually, on high voltage transmission, it is safer to ground the conductors on the tower being worked rather than the two adjacent towers. This is because it puts less resistance to ground from the conductor in the event of an inadvertent tenderization. It also saves a lot of time.

The ground conductor has to be sized to be capable of conducting the maximum available short circuit current for a fair amount of time.

Regards,

John Phillips

I seem to average one 4-14 hour power outage every other year. Other than that I loose power 3-5 times a year for less than an hour.

With those kinds of outages, I couldn't justify the cost of an industrial generator and a professional panel install, so I bought a post y2k returned Coleman generator at Home Depot and came up with a DIY solution.

I'm cheap, but I wouldn't take the risk of backfeeding the whole house. I run the 20a 240v output from the generator into my basement. There I split it into two 120v feeds. One 120v feed powers a twist lock outlet next to the furnace. The other 120v feed powers four outlets at the top of the basement stairs.

I put my furnace on a 120v twist lock plug and put a twist lock outlet on the existing furnace circuit. In the event of a power outage I simply unplug the furnace from the grid and plug it into the generator plug.

My fridge, TV, dish network receiver, and sump pump are within 20' of the four outlets at the top of the basement stairs. The sump pump is normally powered off an extension cord into a ground fault outlet at the top of the stairs, and two extra 25' extension cords are hanging on the wall.

Its not an automated solution, but as long as I don't fall down the basement stairs in the dark, it seems like a safe solution.

A real transfer switch is an enclosed multi pole double through switch. They are built so that it is not possible to throw them all the way from one set of feeds to the other. You have to throw them to center off and then to the other supply. When the switch is in the center off position you can open the cover on the cabinet that is it's enclosure. You would then see that each pole is a hinged blade that can be positioned in one contact jaw, centered off, or in the other contact jaw. Since the pole of the switch cannot be in two places at once and it is not long enough to connect both contact jaws together it is extremely difficult to cross connect the two power sources together.

Compare that to the construction of a molded case circuit breaker. It is impossible to look at the operating mechanism; it can, in fact, fail closed; it provides only a single gap between the two power sources.

-- Tom H