Conecting Generator to Breaker Panel Question

--->Paul

As for why. This is like the kids asking why they can't go out late and hang around with the local riff raff. The kids are just as set on going out as the backfeeding generator user. They will listen and keep asking questions until they can find a half true reason why it's ok.

The "neutral" is a insulated current carrying conductor. No different than the 120,277 or 347 lines. It just happens to be the safest one to tie some part of the transformer secondary to ground for safety and fault protection. You could just as easy tie one of the 120V lines to ground and float the other two. Only problem is that you could get bitten with 240V to ground from one line and 120V from the other line to ground.

If the power line was still not energized but there's a lineman working it bare handed when that main breaker gets closed the lineman may not survive. His widow and kids will be looking to you for support the rest of their lives.

A slightly better scenario is that with the main closed you supply a dozen neighbors with power an that overloads the generator AND your wiring which can lead to the destruction of the generator an the wiring igniting the house. Neither a great result.

Interlocking two breakers in a box with a mechanical interlock IS acceptable by the safety code. But that means the breakers have to be in the SAME box and you can't use your welder breaker as the alternate feed for your panel because the interlock would keep you from using the welder with the main breaker on.

The dedicated transfer switch between the meter and the main panel is the least confusing option and works well.

Gerald J.

My reccomendation is: Don't do it, buy and install a proper transfer switch.

You make some good points. In a properly wired house, you should see no difference between the voltage on the neutral and ground. That does not mean it is safe to treat them as interchangeable. The heavy, bare wire coming into your house is a neutral, not a ground. You'll notice that it is just as big as the two ungrounded connectors. At the main disconnect, the neutral and ground are connected, but are isolated in the rest of the system. If you backfeed through the welder, you are expecting the welder ground to substitute for neutral. This might be OK if you know for certain that the ground is a heavy enough conductor to handle the current, and that it is actually connected properly to neutral. More likely, the ground is too small, poorly connected or just plain missing. This would present no problem for the welder, but it will raise havoc if you try to backfeed through the ground. Better to use a disconnect switch, as suggested earlier.

The nuetral wire is used to complete the 110 loop. It may not be present in a true 220 socket.

The ground wire (bare) is there _only_ to protect you, me, your wife, kids, the neighbor from frying. It also provides a quick short & causes the breakers to pop right away, which helps prevent some types of fires & such. It is grounded to earth locally, and also bonded to the nuetral wire at one spot in the main box of your service. (This confuses people and they thing the ground & neutral wires are the same thing....)

In a perfect world, that bare ground wire will _never_ be used by anything, and could be totally eliminated. It is like an insurance policy. It is there but you hope you will never need it. If you do need it & it is installed wrong, like insurance, you will be very sorry.

If the ground wire is ever used for a neutral wire, it turns the entire ground system into a neutral system - which does carry current! That totally voids the safety of the ground system, and allows all sorts of possibilities - such as stray current or a broken wire to energize the metal outsides of all your stoves, washers, driers, drills.....

It is so easy to hook a water system together & see if it works. If not, try again.

With electricity, it is real easy to twist wires together & make it work for 50 years - an electric 110 curciut only needs one live wire and some path to ground - will appear to work fine..... But if done wrong, it is real hard to see that, and a time bomb is waiting to go off. Might not get you, might not ever get anyone. Or, it might kill someone's kid 30 years from now.....

Sometimes the Code seems a little overbearing, but it is there for a reason - usually learned at the expense of people or buildings....

Just explaining, not preaching. :)

--->Paul

From there, they go on to do 2 totally different things, and should never be connected to each other again. Beyond your breaker box, the nutral is used to carry electricity, and the ground wire is used to protect things.

If you cross them, the ground wire now is conducting electrity, and makes all of your appliances 'hot' at certain times. Very dangerous.

It would be like saying the fire sprinkler system and the rest of the water system connect near the water main coming into the building. So can you tap off the sprinkler system lines just because the pipe is handy to add toilets, garden hose, lawn sprinkler system?

No, because some fire systems don't have water until there is heat, and even if pressurized if you take away water the pipe will be sized too small & not have enough flow/pressure to run the sprinkler. You might not ever notice the 'problem', but if you have a fire you will be real sorry.....

Sorta like that.

--->Paul

The neutral wire goes from the main box collecting voltage from your appliances & such and returning them to earth. This is often a bit thicker wire, esp for heavy loads.

The ground wire goes from the main box and attaches to all bare metal all over, and is used by GFI equipment to bleed extra, stray, or dangerous electricity back to ground. This is often a bit thinner wire, same size all through the building.

With your water system, if you interconnect your hot & cold pipes all throught the house, you will still have water pressure at each faucett. But, it will not be the good cold or good hot water you expect - results will be odd to say the least!

Same with the ground & neutral - yes you can interconnect them throught the house, and you will have voltage at all outlets. But it is _not_ the results you want to have - just like interconnecting hot & cold water pipes willie nilly....

--->Paul

All of the unbalanced neutral current will have to flow through a path which was never intended for anything but a safety ground. If the generator has a relatively high output, and if the loads are distributed unevenly, then the more heavily loaded 120V side will be at too low a voltage, and the more lightly loaded side will be at too high a voltage. The exposed metal of the welder outlet may be at a voltage above ground, creating a safety hazard.

It sounds like the orignal example may involve a sub-panel in a remote building, which is even worse.

There is a little more to the story, and a lot of people's saftey relies on the 'tiny' details.... :)

--->Paul

I'll leave it up to others whether or not it is EVER safe to backfeed through a breaker, but you definitely should not do it through a welder outlet.