What is the liability of a public utility when one of their transformer blows?

Factual Questions
21

I appreciate everyone’s help. Apparently it is a 3-phase, 240V, delta configuration and as such you can get a lot of weird readings. We had the utility out today and the upshot is that we just drew too much power for the transformers to handle. The main breaker box to the building is rated at 200 Amps per leg but the tranformers outside were not capable of providing that much current.

All of this had been inspected and approved sometime before we moved into the building. I am willing to eat the damage caused the first time the transformer blew even though the transformers they had in place were underated for how the building was wired when we moved in. But since we let them know we needed more capacity after the first explosion and then we had two more explosions over the course of the next year I feel that they should pay for the damages in this case. They knew but failed to act and we suffered the consequences. There were 9-12 months between the first two transformers going out so there was time to act.

We are getting a new WYE system with 75kVA transformers put in next week and this should solve the problem but they are being very catty as to whether they will pay us anything for damages. We have decided that when we make the claim we will include a cover letter from our lawyer to to see if we can’t “expedite” the process. Utilities are granted a monopoly so we can’t get our power from anywhere else. This being the case it seems appropriate that if we suffer losses due to their negligence we should have some recourse. We will have to see if the law agrees.

If anyone is interested I will post an update if I learn anything of interest from our lawyer when we talk to him tomorrow.

22

Voluble
I, for one, would be interested in an update on your situation vis-a-vis damages. In your case, i think you have a pretty good leg to stand on and it wouldn’t surprise me if they capitulate once a lawyer is involved. Still… one never knows.

You haven’t mentioned whether you checked your equipment per my previous note and i would strongly recommend that you do prior to them setting you up with a wye service. As i mentioned, one leg of a delta service can be laying against a ground and the motors will continue to operate as normal. However, once you are converted to wye (and you have that reference to ground), you may find that the breaker trips when your power is restored. If that were to happen, it could severely damage your case against the power company as they will point to that problem as the cause of your AC burning up.

I ran into a similar case a few years ago where a homeowner paid $5000 to change a well pump motor only to find out his problem was a $12 lightning arrester in his panel. I don’t know of any power companies that are hooking up new straight delta services anymore and the majority of electricians rarely run into them. Thus, in my experience, most electricians have not worked on, nor recognize straight delta systems and are unfamiliar with troubleshooting them. If you follow the steps in my previous note, you may save yourself some grief. If you have any questions or need any clarification, please post again and i’ll get back to you earliest.

Good luck and Fiat Lux,