Electrial Power Problem

[cleddy]

We had a Bad wind storm recently and a tree fell down on the Tri-Plex wires to the Farm house Meter. Wires were strained and twisted around and at least one seem to be torn lose. Any way there was still at least some power in house that only about 3 lights worked and 1 blew out when switched on. After a week of being in this situation I happen to try the hydrant and it seemed like good pressure yet which surprised me since we have the garden on a timed system.
Our pump is 220 volt submergible pump with pressure tank and appeared to be running and pressure was 30 PSI a week after storm. After turning all the breakers off at box including the Main breaker I still had power at the pump. I do have a little clock w/light wired on one leg of the pressure switch. Not sure if the pump was running but the only way to cut the power was taking the wires off the pressure switch. Voltage at the pressure switch wasn't a clean 240 volt but weird 85-90 volts. How could this pump still be getting power with a messed up service line and all the breakers off?? Would the pump still function with compromised service?? Power company has came and repaired service lines and now every thing is working fine. Sorry for the long post but how was this pump getting power??

 

[Tgrasher]

My guess is your Tri-Plex ground was unhooked, can't explain all the symptoms. I had it happen to me once and it was similar to your experience.

 

[wp6529]

The weird voltages were likely due to a broken neutral connection on the triplex. A broken neutral can cause a lot of damage so it needs to be repaired promptly or at a minimum everything turned off to prevent damage while waiting for repair.

As for why the pump had power with the breakers off, that would seem to indicate it was fed power from before the main breaker. The only thing to do there is to trace the wiring and see where it is being fed from.

 

[wp6529]

My guess is your Tri-Plex ground was unhooked, can't explain all the symptoms. I had it happen to me once and it was similar to your experience.

Without the neutral connection you only have the two hot leads and whatever loads are on the system act something like a resistor divider between those hots and the panel neutral which is normally bonded to ground. This give varying apparent voltages on either leg which can get well above the normal 120V, near 240V which is why one of the light bulbs blew.

 

[leroy in ne]

I have been away from water well business for 40 plus years but at 1 time the only thing permitted ahead of main power service disconnect was a fused disconnect box for the well installed directly after the meter. This being for fire protection in my area, else where?

 

[Watthour]

Fire pumps often have only an unfused switch feeding their starters, or at most over-fuse protection for dead shorts only. Of course, there are no overloads, nor ground fault protectors, nor phase balance protectors.

 

[willie in mn]

I have been away from water well business for 40 plus years but at 1 time the only thing permitted ahead of main power service disconnect was a fused disconnect box for the well installed directly after the meter. This being for fire protection in my area, else where?

That was common in our part of southern Mn too. In case of fire, pulling the main would cut off everything except the well pump. It is a bit hazardous spraying water on a building with live power.