But we found the cause (sort of)
So on Friday we got a job appear where an electrician had been called to a group of three holiday lodges.
Each of these lodges has a hot tub and voltages of about 66V were being measured between the water and the surrounding tiled floor, on each one.
The supply to the lodges is via a 2 wire 11kV line and a 50kVA transformer, from this an underground cable feeds the lodges, each with a separate supply and 2 "industrial" units.
The area being an old quarry, then a transport depot and is in the process of being redeveloped
Earthing is PME (TN-C-S) to all the properties.
Staff attending on Friday could find nothing obvious but by disconnecting at the service positions confirmed 66 volts between the neutral and true earth. They did however disconnect the HV and carefully inspected all the wiring on the transformer.
To maintain supplies, the lodges were connected to individual 20kVA generators over night.
On Saturday the investigations continued with efforts being made to gain access to check the two industrial units, when this was looking unsuccessful the decision was made to excavate the service cables and disconnect the supplies in turn to see if the fault location could be found.
After cutting the cable to the first one, the voltage on the neutral disappeared!
Shortly after this the owner arrived to give access. Inspection showed that this unit did not even have a consumer unit! The supply went from the cut-out via the meter to a 100A Switch Fuse from which all the secondary circuits were fed, nor was there any sign of earthing or bonding!
The supply was permanently disconnected on safety grounds.
Following this the generators were removed and supplies restored to normal.
Something different to think about
So on Friday we got a job appear where an electrician had been called to a group of three holiday lodges.
Each of these lodges has a hot tub and voltages of about 66V were being measured between the water and the surrounding tiled floor, on each one.
The supply to the lodges is via a 2 wire 11kV line and a 50kVA transformer, from this an underground cable feeds the lodges, each with a separate supply and 2 "industrial" units.
The area being an old quarry, then a transport depot and is in the process of being redeveloped
Earthing is PME (TN-C-S) to all the properties.
Staff attending on Friday could find nothing obvious but by disconnecting at the service positions confirmed 66 volts between the neutral and true earth. They did however disconnect the HV and carefully inspected all the wiring on the transformer.
To maintain supplies, the lodges were connected to individual 20kVA generators over night.
On Saturday the investigations continued with efforts being made to gain access to check the two industrial units, when this was looking unsuccessful the decision was made to excavate the service cables and disconnect the supplies in turn to see if the fault location could be found.
After cutting the cable to the first one, the voltage on the neutral disappeared!
Shortly after this the owner arrived to give access. Inspection showed that this unit did not even have a consumer unit! The supply went from the cut-out via the meter to a 100A Switch Fuse from which all the secondary circuits were fed, nor was there any sign of earthing or bonding!
The supply was permanently disconnected on safety grounds.
Following this the generators were removed and supplies restored to normal.
Something different to think about
