Back feeding power to sticks and bricks from generator

[Steve N Sal]

Originally Posted by ahicks

Regarding the neutral, if you look at how your panel is wired, it goes directly to a ground rod that's been driven into the ground outside your house. I doubt seriously if that is going to cause an issue to a lineman. When he's dealing with issues out on the lines, he's going to be expecting that line is grounded. No change from normal for him there?

Regarding a set of main breaker points not opening when the breaker is opened? Oh please... have you ever seen that happen first hand? Even if that were possible, and it did happen, when you connected your gen set to that leg, we're back to the scenario where the gen set is trying to power the neighborhood - which will pop the breaker immediately.

You my friend would never be on of job of mine. Have I seen the contacts on a breaker fail to open??? The answer is yes I have and you think it would pop the breaker immediately, you better think again. Your knowledge of working electrical systems are very bleak. I certainly wouldn't tackle any electrical work any time soon if I were you. Let me ask you where the neutral is derived from??? The very transformer he is working on. Do you actually know the difference between the grounded conductor and the grounding conductor?? If you do please explain it to me. If I were you I most certainly would not be passing on anything relative to explaining electricity.

[the trainguy]

In residential 120 VAC, single-phase electrical wiring, there are three main types of electrical wires:
1. Ungrounded conductor (Hot or "Line" )
2. Grounded conductor (Neutral)
3. Grounding conductor (Safety Ground or Protective Earth)

The grounded conductor is the power return, intended as a current return path from the load back to the source to complete the "circuit."

Its insulation is White, gray or a non-green color with white stripes.
The National Electric Code requires it be connected to earth ("grounded ") at the service entrance and only there.

The grounding conductor is the safety ground which serves as an emergency current return path in the event of a circuit fault or overvoltage.

Like the grounded conductor, it too is grounded at the service entrance, but is also connected to metal surfaces and parts along the circuit, grounding them.
It conducts current only if the current "seeks" to return to the service entrance along a path other than the Neutral (like through your chest, should a Hot wire becomes loose and contact metal in the circuit that you may touch).

Since the grounding conductor doesn't normally carry current, its cross-section is sometimes smaller than the grounded conductor's. The grounding conductor's insulation is green (no other conductors can have green insulation) though sometimes it is bare copper.

Sometimes the steel metal conduit enclosing the Hot and Neutral acts as the grounding conductor but in my 50+ years of doing electrical work I have always run a separate green ground wire in my conduit runs.

[ahicks]

Shoot, I'm always game for learning something new! Admittedly, I have little practical knowledge when it comes to the power grid outside a home. OTOH, I have built and wired 2 homes (that both passed rough and final inspections without a hitch), and I did work on motor homes for 19 years, so I'm not completely inept (as one of you seem to believe?). Let me ask this regarding the neutral?

I think I get the neutral/return concept, and how a transformer works to provide 2 legs with a common neutral. Can one of you explain/provide a logical scenario, of how something I might be doing in a situation like this, could affect a lineman? And if it won't complicate things too much, lets assume there is no current passing through the main breakers for the time being....

Is there a potential for him to get a shock from the neutral coming from my house?



Regarding the breaker whose points didn't open when it was turned off, I'm afraid I'll have to see that one. We're talking a residential breaker, right? From a box with no visible (lightning) damage?

Thanks
-Al

[gemini5362]

let me add some more fuel to this fire.

1. yes the neutral line is still connected when you throw the breakers. I understand the argument about your transformer being a step up transformer. But. What is it going to step up. Theoretically there are three wires coming from your transfer. Now if I disconnect two wires that only leaves one wire connected to the transformer. In my 45 years of electrical work I have always found that it takes at least two wires or connections of some type to carry current. If you only have the neutral wire going to the transformer then you will not get any current flow to step up.

2. In some older electrical boxes the bar for the neutral and the bar for the ground are on each side of the box with a bar running between them effectively making them one conection point. In the electrical panel for my stick and brick home it only has one bar and both my neutral and grounds are hooked into that bar.

3. Double ended cords are highly dangerous. I have done it but again I have 45 years of working with electricity from ships. to homes to large plants with their own substations. I still do not like to do it and I only do it if I am going to be there monitoring it while it is done.

4 Automatic transfer switches are expensive. In my earlier post I mentioned my manual transfer switch I devised it is about 60 dollars for the two A/c disconnects. I wired the important things in my house to the garage panel ( kitchen, bathroom, bedroom.) When I need to use my generator I power these items. The people that use their motor homes for power through an extension cord might want to just use that for their refrigerator. One poster modified his generator on his motorhome to be able to run the cord to the house that is a good idea and he has taken the time to do it safely

The poster that has seen breakers fail to open has seen something I have rarely seen before. I have seen breakers not open at the steel mill where I worked but when we checked they had actually melted and could not physically open. I have never seen a breaker that you could push the breaker to the open position and not have the contacts move. If you have you have been lucky I guess because in 45 years I have not seen that The bigger worry I have is with someone forgetting to open the mains when they hook up a generator

[BFlinn181]

The amount of misinformation, exaggeration, disregard for other's safety in this thread is astonishing! Electricity kills. The fact is most regions have LAWS against hooking up a generator, solar panels, windmills, etc. to anything also connected to the grid without an isolating lockout. To connect your RV generator to your house is ILLEGAL without proper inspection and certification. If you want to run a few extension cords to power refrigerators, lights, or fans, etc., O.K., as soon as you overload the circuits you'll probably trip breakers and learn. But to attempt to tie the RV generator to the house circuits to make it more 'convenient' is hazardous and criminal, especially if you kill a lineman for your 'convenience.' I would hope you get prosecuted to the fullest extent of the law because you disregarded other's safety for your comfort and convenience in a time of emergency.

[tricotec]

Originally Posted by gemini5362

let me add some more fuel to this fire.

1. yes the neutral line is still connected when you throw the breakers. I understand the argument about your transformer being a step up transformer. But. What is it going to step up. Theoretically there are three wires coming from your transfer. Now if I disconnect two wires that only leaves one wire connected to the transformer. In my 45 years of electrical work I have always found that it takes at least two wires or connections of some type to carry current. If you only have the neutral wire going to the transformer then you will not get any current flow to step up.

2. In some older electrical boxes the bar for the neutral and the bar for the ground are on each side of the box with a bar running between them effectively making them one conection point. In the electrical panel for my stick and brick home it only has one bar and both my neutral and grounds are hooked into that bar.

3. Double ended cords are highly dangerous. I have done it but again I have 45 years of working with electricity from ships. to homes to large plants with their own substations. I still do not like to do it and I only do it if I am going to be there monitoring it while it is done.

4 Automatic transfer switches are expensive. In my earlier post I mentioned my manual transfer switch I devised it is about 60 dollars for the two A/c disconnects. I wired the important things in my house to the garage panel ( kitchen, bathroom, bedroom.) When I need to use my generator I power these items. The people that use their motor homes for power through an extension cord might want to just use that for their refrigerator. One poster modified his generator on his motorhome to be able to run the cord to the house that is a good idea and he has taken the time to do it safely

The poster that has seen breakers fail to open has seen something I have rarely seen before. I have seen breakers not open at the steel mill where I worked but when we checked they had actually melted and could not physically open. I have never seen a breaker that you could push the breaker to the open position and not have the contacts move. If you have you have been lucky I guess because in 45 years I have not seen that The bigger worry I have is with someone forgetting to open the mains when they hook up a generator

From a LEGAL perspective:

If you have legally installed a permitted transfer switch to connect your generator and a lineman is injured or killed because of a failure of breaker contacts to open or a damaged connection to a ground rod, it will be deemed an accident and you won't be charged with a crime.

If you have illegally connected a generator to your home's electrical system without a qualified electrician and a permitted transfer switch and the same accident occurs you can be charged with negligent or reckless homicide and imprisoned or face civil liability. I'd rather buy 4 100 foot extension cords and avoid the potential liability by plugging the loads directly into my RV.

[middleman210]

Originally Posted by charlie2

We had a power outage at our house the other day and hooked our garage refrigerator to the outside outlet on the motor home while running off 7500 watt Onan diesel generator. worked fine. Talking to a licensed electrician after words and he said I could have cut the main power feed to the house from consumers power company, plugged the motor-home to the RV outlet I have on the house and it would have back-fed the entire house. Doesn't sound right to me. Is he correct?

Food for thought. I'm an electrician and can tell you what our local power company does first when they come to restore power. They attach a ground to the line they are working on. Dead short to genny. Have known several people who have done the back feed thing and forgot to turn off their main breaker and either when the lineman grounds the line or when power is restored they have burned up the genny. Also if you are putting power back into the grid that means that any of your neighbors could possibly be powered by your genny again causing a possibility of overloading your genny. My advice is to get some on to do things right or you might be looking for a new unit

[wa8yxm]

For Dr.Film There is one transfer system, I do not approve of it myself but it does meet code in most (if not all) areas, that consists of Two main breakers, ONE is connected to the power mains, the other to the generator inlet and a device (Sliding metal bracket) that insures you MUST turn one off before you can turn the other ON.. This is the approed version of your "Throwing the main breaker cutting power to the house" I do not approve of it because there is always some obliviot who will break that sliding block off plate and figure out a way to turn them both on at the same time with disastrous results. I do not approve of NOT using an approved transfer system because, as I said, I have been known to miss a step on a check list from time to time.

The reason I do not use the otcal box and a bunch of extension cords (or rather did not) is because I do not want cords running all over, too much of a tripping hazard. The inlet and transfer panel was way easier once installed.

It also made it very easy to switch over and back.

[fortisi876]

A few questions from reading this entire thread:

1) If I choose to NOT go the multiple extension cord route to each outlet, how else do you get the genny power out of the MH? I tested the 50A plug and it's definitely not powered while the genset is running. I opened up the transfer switch inside the bay and it was showing 120V on each leg, which brings me to question #2!

2) I was surprised to learn that my 7.5K genset does NOT deliver 240V, however, it does make roughly 60A. Am I correct in assuming that the genset sends roughly 30A to each leg to the transfer switch? If yes, again, how do I get each leg out of the MH?

3) I will most likely go the transfer switch route inside my home. For those saying they got theirs for $100....where??? Everyplace I look they're $200-350.


Thanks in advance!

[Mr_D]

To backfeed your house here takes an automatic transfer switch. They won't allow a manual one for obvious safety reasons.

[fortisi876]

One final thought

What do you guys think about making a dbl safe (of sorts) by installing something along this beside your main panel?

First point of business is figuring out how many circuits you need to power up and if it'll meet your generator output, adjust accordingly....then

1) Mount a 2G utility box beside your main panel for a male flush mount receptacle with lid, preferably a locking type if available??
2) Off the top of that box, install a single gang utility box for each needed circuit.
3) For each single gang box piggyback a wire into each needed breaker and install onto one side of a SP switch.
4) The other side of each switch runs into the dbl gang box where the receptacle will be installed. Also tie in the neutral from the 30A receptacle to the buss bar.

Now when a power fails occurs, all one need do is shut down the main breaker along with ALL other breakers. Run your HD cord from genny to this receptacle, make sure all switches are turned off position and go start your genny, come in and fire up one circuit at a time.

I've read about all the concerns in this thread, they are legit concerns. Personally, I've never seen a breaker fail to open contacts all while still appearing to operate as normal BUT I suppose the possibility is still there. However, what are the odds of TWO breakers fusing their contacts in the same panel?

Wired up as described above, I think it'd pretty much eliminate that potential risk most were really concerned about in here. The ONLY dangerous part that comes to mind is when there isn't a power outage the panel would send live current to that male receptacle if the switches are all in the on position, valid concern BUT I think a lockable cover would eliminate that risk.

Thoughts???

[BFlinn181]

Originally Posted by fortisi876

One final thought

What do you guys think about making a dbl safe (of sorts) by installing something along this beside your main panel?

First point of business is figuring out how many circuits you need to power up and if it'll meet your generator output, adjust accordingly....then

1) Mount a 2G utility box beside your main panel for a male flush mount receptacle with lid, preferably a locking type if available??
2) Off the top of that box, install a single gang utility box for each needed circuit.
3) For each single gang box piggyback a wire into each needed breaker and install onto one side of a SP switch.
4) The other side of each switch runs into the dbl gang box where the receptacle will be installed. Also tie in the neutral from the 30A receptacle to the buss bar.

Now when a power fails occurs, all one need do is shut down the main breaker along with ALL other breakers. Run your HD cord from genny to this receptacle, make sure all switches are turned off position and go start your genny, come in and fire up one circuit at a time.

I've read about all the concerns in this thread, they are legit concerns. Personally, I've never seen a breaker fail to open contacts all while still appearing to operate as normal BUT I suppose the possibility is still there. However, what are the odds of TWO breakers fusing their contacts in the same panel?

Wired up as described above, I think it'd pretty much eliminate that potential risk most were really concerned about in here. The ONLY dangerous part that comes to mind is when there isn't a power outage the panel would send live current to that male receptacle if the switches are all in the on position, valid concern BUT I think a lockable cover would eliminate that risk.

Thoughts???

It wouldn't be legal in most places. Too many chances for switches/breakers not set correctly, allowing power back into the grid. Do it legally or not at all.

[TQ60]

Too much work and not really safe.

This is real simple.

First assumptions...
1. Generator will output only 120 vac so all output will be considered unballanced.
2. Transfer must be automatic
3. Only critical loads required
4. Some not critical loads okay.

First due to assumption 1 you will need to be real careful regarding neutral current carrying capacity.

And you may need to redistribute your panel breakers.

Now determine the location of critical loads.
A. Fridge
B. Freezer
C. Electric support for heating system.
D. Water pump in well. If 120 vac.

Non critical loads
A. Tv
B. Computer/internet/phone

Locate the circuits each of the loads and pick up a subpanel that has room for the amount of breakers plus a few spares and be sure it is rated more than your generator...twice the amount.

Try to get one that takes same style breaker.

Pick up a single breaker rated for generator output.

Wire correct size too.

Pick up a rv ATS or just a DPDT contactor rated for generator output plus some and make your own, if you need to know how dont...

Locate the subpanel close to the main panel with suitable conduit between them.

Mount ATS in same area with suitable conduit.

Mount suitable connection for generator input with conduit connection to ATS.

Since all generator supported loads are 120 vac and on same leg you will need to move other circuits to balance the loads across the 2 mains.

Add a suitable wire for safety ground to the subpanel to connect to main.

Be sure neutral and safety grounds not connected together in subpanel.

Remove the breakers one at a time and extend the black and white wires to the subpanel.

Safety ground can stay put.

Place the breakers in the subpanel and connect the extended wires to breaker and neutral buss.

After all breakers are moved and circuits extended time to wire ATS.

Locate position in old main panel for new large breaker.

Install breaker label as feed to generator subpanel.

Supply route and connect suitable wire from breaker to line side of ATS.

Supply route and connect suitable wire from ATS LOAD side of ATS to line lugs in subpanel.

Supply route and connect wire from ATS GEN port of ATS to generator connector.

If ATS has generator control you can wire that too but not discussed here.

This process allows generator to support the loads with minimal cost...subpanel less than 50 bucks and the ATS maybe 250 or so.

Yes it can be done with disconnects or other processes.

This one is a little bit of work one time.

And it would need to be done to meet specific local code, this is a high level description for demonstration.

There are many commercial MTS that ate simple interlocked breakers but they are intended for sequence switching as they are not designed for load switching.

This has been beat to death...this is not a place to cut corners as doing it correctly does not cost much more than doing it unsafe.

[fortisi876]

Ok all that sounds fair enough for the interior work but how do you connect to MH? What needs to be done there?