Some of these ballasts could have been burned from an overvoltage.

I reckon they did a mass re-lamp on that street and used a faulty batch of lamps or it could just be due to the lineys not giving a toss about them.

About 30 percent of Concord,NH’s street lights are out. Since Unitil doesn’t have a repair page or email.

The HV to LV short would not last long enough to cause the lamps to leak.
But it could be some loose Neutral, if the loads are star connected...

About 30 percent of Concord,NH’s street lights are out. Since Unitil doesn’t have a repair page or email.

This is the only road I’ve seen that is out, because it is maintained by the city. The SCE utility maintains their lights fairly well.

@Medved

What does it mean to have star connected loads?

Star connection is 3 phase wiring where the 3 actives go through the load and the neutral are all tied together. There is also Delta configuration where the loads are between the phases. Which would give a full phase to phase voltage. Here in Australia we have 240V single phase and 415W three phase. With Star you have 415V between the phases and 240V to neutral but with Delta you have no neutral so there is only 415V. Delta is used here for power distribution or big factorys with powerful machinery. For small industrial, commercial and residential we use Star which lets us have 415V and 240V. If you had a larger house you'd have 3 phase and split the loads across that, if you had a smaller house you would have single phase on only one phase and neutral and other houses would alternate on different phases.

Hope that helps but keep in mind I'm not an electrician this is just what I have learned.

Star connection is 3 phase wiring where the 3 actives go through the load and the neutral are all tied together. There is also Delta configuration where the loads are between the phases. Which would give a full phase to phase voltage. Here in Australia we have 240V single phase and 415W three phase. With Star you have 415V between the phases and 240V to neutral but with Delta you have no neutral so there is only 415V. Delta is used here for power distribution or big factorys with powerful machinery. For small industrial, commercial and residential we use Star which lets us have 415V and 240V. If you had a larger house you'd have 3 phase and split the loads across that, if you had a smaller house you would have single phase on only one phase and neutral and other houses would alternate on different phases.

Hope that helps but keep in mind I'm not an electrician this is just what I have learned.

Thank you for all the info! I’m guessing that the lanterns containing the leaked bulbs were either wired at 120 or 240V. I haven’t seen much standard street lighting wired in star connection at 277V (US three-phase power) here. They are definitely not wired for 480V, which is all that I can be sure of.