Wow Did I Goof Up

John B. · Jul 23, 2016

For the last ten years I've always used my 220 volt outlet for my air compressor and for my standby generator just for my shed. I unplug the air compressor then plug in my 10hp generator and back feed to the breaker box but first throw the main breaker so it's off the grid. So all I power is the shed. Well last weekend I went to plug in my air compressor and accidently grabbed the plug for the generator and sent 220 volts back into the generator. It hummed about 2 seconds until I realized what I did and quickly unplugged it. Now the generator doesn't work. I found one of the two diodes bad inside the generator. Replaced with exact same kind and number and it still doesn't generate. I'm getting erractic voltage at the outlets with my digital multitester. I need to get me a analog test meter and do some testing. This generator is a Guardian model C5CM 4200 watt. I googled this model and nothing comes up. Any ideas where I can find more information on this generator? Thanks for an information...

John B.

David G · Jul 23, 2016

You got by a lot cheaper than killing someone.

It was pretty STUPID leaving the equipment so easy to connect.

Please NOTICE I capitalized STUPID.

That is why they make transfer switches.

jamesinok · Jul 23, 2016

Guardian is a brand name Lowe's sells. They are manufactured by Generac

David G · Jul 23, 2016

I will apologize for my tone, as an electrical engineer, I have worked with enough lineman, that this is a sensitive issue.

bingo71 · Jul 23, 2016

I agree with you David G

bingo71 · Jul 23, 2016

That makes my skin crawl---NO PUN!!!

Greg1959 · Jul 23, 2016

I have to assume that the generator was not running. Otherwise, why would his intentions be to plug in the air compressor? If the generatoer was not running then he wouldn't have hurt anything other than the generator.

Maybe I am missing something that has you all tore up?

john in la · Jul 23, 2016

I have to agree with Greg1959
No way he was electrocuting anyone since it seems the generator was not running.

Steve@Advance · Jul 23, 2016

Have you tried to "flash" it?

No, not like that, try this!
flash it

old · Jul 23, 2016

Your goof was simple but costly since you may have burned up your generator. It is better and all to have a disconnect installed by the power company so you can power your place but not back feed the system. The way you had it could sooner or latter get up in trouble with the power company if they found out about it. All it takes is you forgoing to trip the breaker and you could then kill some one

Billy Shafer · Jul 23, 2016

In 45 years I have seen plenty of back fed generators. Most common thing is it destroys the rotor and stator. Have a 15 KW in the shop that was back fed. Repairs will run just over 2400.00 dollars.

FBH44 · Jul 24, 2016

Backfeeding onto the utility company during outages, inadvertent or not, can kill linemen trying to get YOU back in power.

ericlb · Jul 24, 2016

hope the linemen are all ok, thats why when power is out and i need it i plug each item into the generator itself as a stand alone deal, not into the breakerbox

showcrop · Jul 24, 2016

(quoted from post at 20:34:30 07/23/16) I have to assume that the generator was not running. Otherwise, why would his intentions be to plug in the air compressor? If the generatoer was not running then he wouldn't have hurt anything other than the generator.

Maybe I am missing something that has you all tore up?

The point is that the mistake COULD have been failure to turn the main off when intentionally using the generator for power. The generator would have powered the grid which could be harmful to linemen working to restore power to lines that they had tested as dead. Rather than a transfer switch I use a sliding lockout at the top of my breaker box, which enables me to have all of my circuits.

Billy Shafer · Jul 24, 2016

Guardian is made by Generac. Good luck getting any help from them.

What I have seen over the years on back feeding a house. If something goes wrong.
Damage to the house including fire.
Insurance canceled as soon as they found out what was done.No claim paid.
Power company will pull your meter.
Large fines for code violations.
You get to pay for all damage done.Including any done to adjoining property.

I hear it all the time. I have been doing it this way for years no problem. All it takes is the first time.

ss55 · Jul 24, 2016

I know what you meant. Maybe it would have been more accurate and more appropriate to have said "CARELESS and DANGEROUS"?

1948CaseVAI · Jul 24, 2016

I am positive I would never admit to doing something that under other circumstances could have led to the death of innocent people.

Not having a proper transfer switch isn't laziness, it is cheapness. Please either do not fix/replace your generator or else have a professional transfer switch installed immediately.

I think the price of the damages is small compared to what price could have been paid.

redtom · Jul 24, 2016

Not trying to be a wise acre, but I have an honest question. I you were to accidentally backfeed into the "grid" during a power outage, wouldn't it just stall your generator? My genny is fully loaded with my house, if I try to much she'll bog out and die. If I loaded it with all the houses down the road during a power outage the massive load would just stall it out.

K Effective · Jul 25, 2016

Not trying to be a wise acre, but I have an honest question. I you were to accidentally backfeed into the "grid" during a power outage, wouldn't it just stall your generator?

Correct, assuming there are many loads still connected to the dead feeder line. But for that instant, you are feeding the line with stepped up voltage at some very small amperage. AND, if a repair person is working that line between you and the grounding devices, the repair person could be exposed to line voltage. Current, at high voltage, requires less than a cycle to kill a human.

I think the point is, that the original poster had made his particular set up too easy to perform. There has to be something to force the disconnect from normal grid power prior to connecting generator power. Most here advocate a transfer switch which is a mechanical failsafe. Some systems rely on procedure use for hookup. Many back-feeders just hope they remember to open the main first.

NW Ohio Tim · Jul 25, 2016

So I'm assuming to run this setup, you have a cord with two male ends??

That is at least as dangerous, if not more, than accidently back feeding the lines, in my opinion.

Buy a switch.

Tim

GeneMO · Jul 25, 2016

We pugged in a small generator into the house feed back in the 1980's when we had a 4 day outage due to big ice storm. We just went out to the meter pole and pulled the meter. No way of hurting anyone then.

I am building a new house and have figured in a 16kw Generac with all the proper switching, etc.

Gene

Wow Did I Goof Up

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