[SOLVED] Generator backfeed revisited

[Tom Horne]

That of course depends on how you do it. There are relatively inexpensive ways to do it safely that anyone who can wire up a suicide cord could install for themselves.

-- Tom H

[John Gilmer]

Well, there are appoved panels that have a mechanical interlock to ensure that only one of two breakers is engaged at any time.

IOW: the type of failure you described is considered rare enough that it isn't considered to be a serious safety issue.

[Toller]

I don't recommend testing the matter, but unless your generator is grounded, you can't get electrocuted that way. A severe electrical burn sure, but not electrocuted. Think about it; what circuit are you completing if you touch one prong? (okay, if you touched one prong with each hand, you could get electrocuted, but that is reaching.)

[Newby]

[snipped]

There is a connection hub that mounts on the meter base. You plug your generator into it and manage your load off of your regular breaker panel. You can buy one from Dominion Virginia Power for $995. Follow the below link to Dominion Virginia Power's page.

Research on the web shows that some power companies will lease the device to their customers for less than $10/month; Dominion won't.

A thousand dollars is a bit steep for me to pay to be able to connect a generator to my house for the occasional power outage.

[Eric]

You know, its because of people doing things like this that we end up with laws prohibiting it, which in turn makes it more expensive for insurance, installation and equipment to protect against doing it. Why not do it right and get a transfer switch? Is it really worth saving a couple of bucks when you run so many risks? The "I'll never do it" and " no one but me will touch it" excuses have killed and injured many. Really, please dont cobble together some lame system that puts others and yourself at risk. Eric

[volts500]

Which is exactly what the OP said that he is _not_ interested in using.

Electrical accidents are often due to either poor wiring or ill-advised behavior on the part of the victim. I can fully understand that some people who have never seen a breaker that won't open when turned OFF and/or trip on short-circuit can come to the ill-advised conclusion that it's a rare occassion; even assume that just because they turned a circuit OFF that it is deenergized and further arrive at another ill-advised conclusion that checking for voltage is not necessary. Interesting how those persons are usually the very same people who make the biggest stink about it (if they are still alive) when/if something does happen to them or others regardless of fact that their actions were based upon their own ill-advised conclusions.

[rb608]

As the OP, I'll add an anecdote on this very tangent. I was rewiring an attic light, and being uncertain which breaker was which, I turned the light on & flipped breakers until it went off. In an unusual fit of caution, after opening up the junction box, I tested all of the wires inside. To my surprise, there was still a live circuit in the box. The previous homeowner had run two breaker circuits through the same JB. Coulda been unpleasant. Ya just never know unless you check.

Joe F.

[Chris Lewis]

According to rb608 :

During the great 1998 ice storm, a friend and I spent some time "inspecting" homeowner generator installations (as a favour to a neighboring township, who by and large were without power for almost a month). We saw a couple of backfeeds, but none of the suicide-cord variety. And we did one ourselves (of a 100Kw generator into the publics works garage).

Or in an earlier situation, someone doing a complete rewire (new panel in a different location) was caught in the middle of a strike and couldn't get the feed moved. So the electrician backfed the new panel via a dryer circuit. In fact, _suggested_ by an inspector.

During an emergency, you do what you gotta do.

That being said, while a suicide cord is "simple", it's quite unsafe in a number of ways, and frankly, while you'd probably get away with it, it's _unnecessarily_ unsafe.

_Unless_ you install a transfer switch, I recommend you use extension cords. If, after the power is out for a day or more, and there's no expectation of power restoration _soon_, and you must must must have backfeed, then consider backfeeding. Instead of a suicide cord, do this:

1) Do what you have to do to disconnect the main feed. Hopefully in a way that's easy to restore when the power comes back. Just switching the main breakers off isn't good enough (even with lockouts). Pull the breakers, or pull off the output of the main breakers. Or something. Pull the meter if you have to (and cover the hole). 2) Direct wire the generator into the main panel or outlet (presumably a dryer outlet or something else large ampacity).

When power comes back, take your time and make absolutely certain you have the sequence right. Turn off the generator _first_.

[RB]

This is permitted by the NEC I think and it is one area that I take strong exception to. In residential wiring I'd like to know that only one circuit feeds a given device.

RB

rb608 wrote:

[Doug Warner]

Here's my DIY panel: I chose SPDT switches with a large break-before-make transition, and to the transfers with the genrerator off.

Note that the circuits don't have overload protection in generator mode, but, since the gen only outputs 3000W, and shuts down at about

28A, I didn't add breakers.

To help juggle loads, I added a remote meter at the top of the basement stairs, fed by a current transformer in the transfer switch box:

I already had a small subpanel box, which I stripped, cut, added the switch support, etc. I don't think it cost over $150, while dedicated transfer panels with the same number of circuits were over $300. =20

Downside: One of the switches went permanently open when I transferred the kitchen quickly under load. The refrigerator was probably running, and the inductive kickback of the compressor motor against the steet supply killed the switch. The main panel breaker did not trip on this "overload" =20

I'd probably do it over if I could find SPDT breakers that could handle overload protection AND transfer in one unit.

To reply, please remove one letter from each side of "@" Spammers are VERMIN. Please kill them all.

[RB]

The other downside to this is that if you attempt to sell your house you may well have to remove it since it doesn't comply with the NEC. Additionally, insurance companies are looking for ways to avoid loss payments with greater frequncy. They'd likely give you a hard time.

RB

Doug Warner wrote:

[John Gilmer]

The problems with the DIY transfer panel are: 1) only 120 volt loads and be switched; and 2) lack of protection since EVERY circuit could draw 28 amps including "lighting" circuits which are often only 15 amps.

The NEC owes it to the American Public to properly address the home generator problem. When they look at things hard they take account of human nature. They may well find (or encourage others to find) cheap ways of backing up the home power with a generator.

That would be 100% up to the buyer (and whoever writes the mortgage.) Houses are routinely sold (with FHA loans) that have sub-standard wiring. There seems to be a "don't ask, don't tell" about this sort of stuff.

In what sense? I have lost count of the number of home insurance policies I have had on various places and NOT once has the company inspected the wiring. The ONLY thing one company did was to send a guy to walk around a house we got at a bargain to ensure that is really was as big as we claimed.

If a house burns down and it is caused by faulty homeowner wiring in most places the insurance company will still pay. If they don't pay they risk the state regulators fining them. If it goes to court, a jury of homeowners (each of whom likely has a bit of "faulty" wiring) will take the insurance company to the cleaners.

Where I live, insurance companies can't hide behind pages of fine print. If they want to get into the wiring inspection business they can; but if they do, they have effectively "approved" the situation which can expose them to third party liability directly rather than as an insurer to the homeowner.

In practice, the companies recognize that they are PAID to assume these risks. The collect the money and if something happens they pay up.

The only crisis in homeowners insurance comes when home prices are falling and the only way homeowners can "cash out" is for an "accident" to happen.

[Mark & Mary Ann Weiss]

To begin with, this is dangerous. However, it can be done practically.

I have mine setup in a super-cheap manner. Outside, in a cement block house with a poured slab roof, a 12kW electric start Generac, wired to a dual

30-amp breaker via #8AWG cable. I have that breaker clearly marked with a label that says "Turn off main breaker before turning on this breaker" as a reminder of the sequence and to minimize human error. I am the only person in the household authorized to make the transfer. When the Aug 14th blackout hit, I started the Generac, turned off the 200A main breaker and turned on the dual 30A breaker, feeding Generac's output to both sides of the bus. Voila, normal household operation (excepting my 10kW sound system, which has a peak draw of over 15kW at full power output), but everything else, well pump, stove, air conditioners, works fine. And never in 18 years have I failed to execute the transfer procedure properly. Granted, if I had a lot of money to spend on it, I'd get a 200A transfer switch and a CAT diesel generator and automate the whole process, but this jury rig works and outages are not that frequent. The only way to do this is at the breaker panel. I would not feed back into an outlet. I don't recommend doing this, unless you can garantee that you won't be backfeeding into the electric grid.

-- Take care,

Mark & Mary Ann Weiss

VIDEO PRODUCTION . FILM SCANNING . AUDIO RESTORATION Hear my Kurzweil Creations at:

sites at:

-

[Mark or Sue]

Why do you only have a 30A breaker on a 12KW generator?

-- Mark Kent, WA

[m Ransley]

He is using a dual 30 , 30 for each 120 leg or 60 total.

[Mark & Mary Ann Weiss]

Because until recently, we had a 5kW gasolene-driven recoil start generator--it's the same breaker. I may choose to upgrade it eventually, but during the last extended outage, we didn't use enough juice to trip the breaker.

-- Take care,

Mark & Mary Ann Weiss

VIDEO PRODUCTION . FILM SCANNING . AUDIO RESTORATION Hear my Kurzweil Creations at:

sites at:

-

[Mark or Sue]

120*60 is 7.2 KW and 240*30 is 7.2 KW.

-- Mark Kent, WA

[Tom Horne]

They have. It is called a generlink.

catch they provide it as a monthly billed service. A mere twenty dollars a month. That is not a typo they get 240 dollars a year for it and that to me makes paying for transfer equipment quite reasonable by comparison.

-- Tom H

[zxcvbob]

How much would a 200A DPDT switch in a NEMA 12 (weatherproof) enclosure cost? Put it between the meter and service panel and use it as a manual transfer switch. Not everything has to be automated...

Best regards, Bob

[Mark or Sue]

$299 from Harbor Freight Tools (assuming NEMA 3R enclosure is OK).

-- Mark Kent, WA