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So my Internet went out last night and came back on but at 6am it was out for good. The Internet company sent a tech to check on it and he came 3hours before he was supposed to so no one was home. He said he found the problem and the Internet wire had melted "the coating melted" fixed tested and it works. Then he said to call the electric company because neutral coming in to the house melted his wire and it's a fire hazard. We called the electric company the opened a work order and said it would take 3 to 5 business days. A couple hours later the guy from the electric company shows up. He pulled the meter off and tested things and said he neutral coming off the pole, it's underground - if that makes a difference, was bad. He took some kind of hand truck like machine off of his truck and hooked it up to the meter and put a metal stake in the ground for his machine. He said a contractor will be out in the next 30 days to replace the wire. He said it's an old wire so they don't fix them they just replace them. He said the machine he left acts like an inverter. That doesn't really make sense to me. So what is the machine doing and how does protect my house until the electric company fixes they bad wire? Bonus points if you can shed some light on how an underground neutral power line goes bad? Everything else in the house seems to be fine. We did have some thunderstorms and rain last night and earlier in the week.

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    A picture of the "machine" might be helpful. I'm thinking it might be a transformer with a 240 volt primary side, and 240 volt secondary with a center tap. Grounding the center tap and connecting it to the neutral line at your panel would give you standard 120/240 volt service while bypassing the neutral wire feeding the house.
    – Mark
    Commented Jun 14 at 0:09
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    @crip659 The power company is not going to leave a customer in an unsafe condition awaiting future repairs. If they have not disconnected the power they have surely temporarily solved the broken neutral in a manner that will not get them sued into the stone age. They will disconnect you if they have no other way of making the house power supply safe.
    – Ecnerwal
    Commented Jun 14 at 0:24

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Likely a transformer, or autotransformer (or it could be an inverter, with current tech) making a new neutral, so the problem becomes fix when convenient rather than Fix immediately.

Just need to take the 240V incoming power and ignore the broken neutral to the pole, and output 240V with a center-tap so each side is 120V to ground, and feed that to the house. The simplest "old-tech" way to do this would be an autotransformer with the ends connected to the 240V supply and a center-tap for the neutral - replicating what the 240V side of the transformer on the pole looks like. Doing it this way means the autotransformer only needs to carry the imbalance current between 120V legs, rather than carrying the full house current as a transformer with a primary and secondary coil would have to do.

Given the savings to the power company on "schedule a contractor" rather than "Emergency rates" they could well afford to have such a thing on hand to solve this common problem safely until a repair can be made, without it being a panic job. When your house is repaired, it goes back on the truck for the next house needing it.

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What happened: search for past answers with the phrase "lost neutral"; it's been described in some depth at this point.

Re what the machine is: could be anything from transformer to motor-generator to what amounts to a big UPS; photo or at least labelling is necessary for us to do more than guess. But what it's doing is isolating your house from the rest of the grid, establishing local power with its own neutral and safety ground independent of the neutral the power company should be supplying but apparently isn't. This isn't an efficient solution, which is why it isn't the usual setup -- but it will work well enough to keep you powered, and keep you safe, until a proper repair is done.

If you want specifics, give us more details to work with.

But I wouldn't worry about it; the last thing the electric company wants to do is set themselves up for a negligence lawsuit.

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