This is pretty much standerd operateing proceedure for the utility companies.They do it all the time and I haven't herd of any problems.
I think they use a transformer but if I remember correctly they normaly say you won't have full power until the problem is corrected.
The good thing is that when they get around to fixing the problem it may even mean a completely new cable. Around here in areas where the underground cables are gettting really old they decided just to replace them over a period of time. If you have a problem you can get bumped up on the list for replacement.
Unless it was cut I think most of the burned neutrals were in areas of old cable.
Well hear it is, you get to hear of a problem that actually happened to one of our jobs.
A customer was having problem with power so they called PoCo and they used that "transformer on the dolly" it was late evening and the service guy found one of the legs of underground lateral failed so he hooked it up as he didn't have time or help to pull in a new line. Several days went by, then a fire broke out near the service equipment outside. Luckily the home owner was home and was Ok but shook up as she saw sparks and fire thru her window under the the meter-base it eventually went up the wall outside then into the attic. Well a full out investigation happened with attorneys, insurance companies, inspectors and electrical professionals. Pretty hairy stuff!
I requested to have the lateral dug up durring an on site investigation to find out more about why they had a problem and it was found that a rodent had followed the underground PVC conduit chewing the cable exposing the aluminum to water/elements until it oxidized to the point of failure and that it had built a nest in the meterbase as one of the PoCo guys told me.
What they didn't realize was that the neutral was also compromised and when the homeowner did laundry it must have put enough load coupled with the increased load of recreating the faulty leg with the transformer it put an excessive current on the grounding system and the cable/phone shielding which initiated a fire in their demarcation boxes below the meter. The fire then burnt into the service lateral that's when the sparks really started to fly which is what she saw.
So yeah, that transformer on a dolly needs to be used with great caution. After talking to friend that worked for another PoCo about the incident he called it the Beast of Burden hence its use. And that they definatly need to be used with great caution when the actual condition of a cable is not known.
