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Using Ground for Neutral Generator

Posted by plantgrower (My Page) on
Sun, Aug 28, 11 at 20:04

I have a generator with a floating neutral. I know I will catch a lot of flack for this but I fully understand the dangers of backfeeding. I live in an area that has many power outages and a lot of people use generators. The linemen in this area never assume a line is DEAD because of the heavy use of generators. Anyway I am hooking up my generator to my house and I need to put it behind my fence to keep it from getting stolen. I decided to use my AC disconnect box to wire in my cord. Only problem is that they have it wired with 8-2wg
My generator has 2 hots, 1 neutral and one ground. The ground wire in the disconnect box looks like 10ga. solid. Since there is nothing else on that circuit and the ac will not be used when the gen is running, can I hook up both the neutral and the ground to the ground wire lug in the disconnect box? Because of the 10ga. ground will it carry 30 amps? Do I need to sink a ground rod?


Follow-Up Postings:

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RE: Using Ground for Neutral Generator

If you're not going to go anywhere near the legal code with your installation, I'm not even going to waste time explaining everything that is wrong with the above.
The fact that you are in a high crime area or one that experiences frequently outages doesn't give you exemption. In fact, the latter just begs you to do it properly.

You might have a little concern for the safety of others even if you don't give a hoot about killing yourself.


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RE: Using Ground for Neutral Generator

I didn't ask this question to start a competition to see which one of you could chastise me most. I was looking for answers to the three questions I posted. I know there are some very intelligent people on here and also several that want to let everyone know how intelligent they are.


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RE: Using Ground for Neutral Generator

"I was looking for answers to the three questions I posted."

Most if us are not in the habit of teaching folks how to do it wrong.


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RE: Using Ground for Neutral Generator

I would not do it that way if it was mine.


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RE: Using Ground for Neutral Generator

I'm not intelligent enough to answer your question.


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RE: Using Ground for Neutral Generator

Let me put it this way.

No, you can not backfeed the A/C circuit without doing other modifications (such as securing the remote breaker from removal).

No, you can not use the ground for a neutral.

No, a ground rod will not help.

No, you can not operate the generator without a provision to isolate the service no matter how savvy the linemen are.

No, you can't feed #10 wiring if the protection at the generator terminals is greater than 30A.

There's probably more things that make this illegal.


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RE: Using Ground for Neutral Generator

If you had 1 minute to get your TV back on or the world would end, then your plan would do that. You obviously know it isn't the right way to do it and that you will be creating a dangerous situation.

Since this isn't an emergency and you are just planning for frequent outages, why not take the time to do it properly?


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RE: Using Ground for Neutral Generator

First, you should be aware that normal circuit breakers are NOT listed for backfeeding and can fail quickly (if backfed.) They normally say "load" and "line" on the poles of a normal breaker, the wording is different on a breaker that's been tested and listed for backfeeding. (I've never seen one, myself, they are somewhat rare.)

That being said, as I see it, you really only have two choices. (Forget your questions, your in bad territory as your currently set up)
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(1) re-wire with 10/3 w/g to a new 240 v inlet box, add a 30a 2-p breaker and a mechanical interlock.

The wire will run around $2/ft., say $20, the inlet box should be under $50, the breaker will run $16 and I just bought a Square D interlock at the local jobber for $16. Add $35 for the electrical permit.

Around $150 to get legal and safe.
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(2) In lieu of that, install a generator interlock box. Re-route the gen input into this box, and choose which circuits you will need (box has 4-120 volt circuits and 1-240 volt circuit (that can be changed to 2 more 120 volts circuits.) Add $35 for the electrical permit.

This will run under $300 but may be simpler to install.

If your unfamiliar with these boxes, you run the gen input into the box, it has flex conduit to your main panelboard (needs be be located right next to the main panel) and has two colored wires to each existing circuit. You remove the wire to the existing circuit breaker, use a Scotch lock to the wire and the other goes to the breaker. During an outage, you run the generator, then switch each circuit at the gen box over to gen input (provides interlock, preventing backfeeding.) Very safe and simple.
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Remember, in ALL cases, you probably need an electrical permit to change the wiring.
(1) it may be the law,
(2) your homeowners insurance may require it to pay out a claim (they WILL DENY your claim if they find out that you modified the electrical system and did not get a permit.
(3) just to have a second pair of professional eyes look over your work and make suggestions to help keep you safe.
(4) to offer a future purchaser of your home a guarantee that the work done was safe.

True story:
The last home I owned, caught fire and their insurance company came after me to collect the $40k. I was able to prove to them that I did NOT do the work and they sued the previous owner (the guy I bought it from) for the loss.

It NOT WORTH skipping over the measly $30-$40, cost of a permit just to avoid having to deal with an inspector. If it EVER fails and causes a fire, or God-forbid an electrocution, YOU will be held responsible. This could happen as much as 20-30 years in the future.

(And bad karma as well).


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RE: Using Ground for Neutral Generator

Normal breakers usually can be used for backfeeding but the code requires them to be screwed down. You need to size the wire to the OCD on the generator (the one back in the panel won't cut it).


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RE: Using Ground for Neutral Generator

I priced a 30A. transfer switch at Home Depot today. It will do 6 circuits. It is $279 and is easy to hook up. All things being considered this looks like the way to go. Thanks for the input. I realize that since the ac circuit is a dedicated circuit their would not be any chance of making a chassis energized anywhere in the circuit. I understand the importance of isolation. What I don't understand is the problem of tying the neutral and the ground together since they would be bonded in the panel at the end of the ground anyway. An electrician friend of mine explained to me that all new panels have un-bonded neutrals and grounds and that is why they are using 4 wire connectors now. In the future as most of the people on here seem to be more interested in complying with code than anything else. The following replay by Bill was the best I got.
"If you had 1 minute to get your TV back on or the world would end, then your plan would do that. You obviously know it isn't the right way to do it and that you will be creating a dangerous situation.

Since this isn't an emergency and you are just planning for frequent outages, why not take the time to do it properly?"
I will probably not be posting anything on here in the future. Tally-Ho


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RE: Using Ground for Neutral Generator

"What I don't understand is the problem of tying the neutral and the ground together since they would be bonded in the panel at the end of the ground anyway."

This is the ONLY place they are connected.

Any other connection after this would mean that the return current on the neutral will also be shared with the ground.

The ground should NEVER carry a current unless a fault has occurred.

If the ground is carrying ANY current there WILL be a voltage drop, and the ground will NOT be at zero volts at the end of the wire.

This is a hazard.

While resistance through dry skin is high enough to prevent a lethal current from flowing, wet skin (especially) is much lower resistance and a lethal current could flow from the no longer 0 volt ground to a lower voltage ground (like the earth).

While the earth is a poor conductor (it may not trip a breaker) the 15 amps of a breaker is much higher than the amount of current needed to stop you heart and kill you.


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RE: Using Ground for Neutral Generator

"normal circuit breakers are NOT listed for backfeeding and can fail quickly"

The current already reverses 120 times a second in normal operation.


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RE: Using Ground for Neutral Generator

backfeeding..no

if you don't understand the difference between a single point ground and neutral..then NO!! don't do it..
you don't know enough about wiring and electricity..
if you do?? why are you asking??

ground..ground wires..carry NO current. until a fault happens
neutral..CARRYS the SAME CURRENT AS THE HOT LEAD!!!
GOT IT!! IT CANNOT BE MADE MORE SIMPLE!!
if not..consider this
the chassis of the appliance you touching is..on GND(or on Neutral..or something above gnd..gee 5-50-100volts??you decide..are you DEAD!!.opps too much current..

do think I'm taking this lighty..no..people have died..DIED !!! ..DIED!!! go it!!! Ground is important..
it IS NOT NEUTRAL!!! NEVER!!!..
NEUTRAL carries CURRENT
GND doesn't unless a fault happens

GOT IT!!!

what else can I say..

-dkenny


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