Fred B
Senior Member
- Location
- Upstate, NY
- Occupation
- Electrician
Customer called about an exceptionally high electric bill. Went to check, things found may or may not be directly related to the high bill. Opinions as to each if can or cannot be related welcome. To start with one issue I've had on this call was when I arrived found my amp meter not functioning (how do I know? multiple items running and 0 Amps but POCO meter spinning like mad.) But moved on with investigation.
Back ground: older Mobil home, someone rewired at some point.
Findings:
Main Disconnect: Voltage high, but normal, evenly distributed 249V LL 125/124LN. Both Neutral and Ground connections had improperly made or damage, cut off/missing parts of multi strand conductors, not all of conductor strands under pressure connector.
Inside panel: Voltages similar to outside panel. Found multiple circuits that had mixing of neutral and grounds on wrong buses. 2 circuits had neutral on the ground bus. (Yes panel N/G unbonded). Nearly every circuit termination was loose, some as much as 2 full turns to get listed torque. 2 circuits had visible heating of neutral wires (discoloration). One of which was related to a circuit HO had been using a portable heater that cord and plug had gotten very hot (reported by HO). Receptacle was very discolored. No breakers tripping. That circuit also was one that had neutral on the ground bus. HO reported that he later used the heater on a different circuit without the plug getting hot.
Pulled the discolored receptacle, found severe arcing evidence with partial meltdown, worst on the neutral terminal.
Without an amp meter was only able to semi check for draw by observation of meter spin. After repairs made to inside panel and bad receptacle, rechecked meter spin. Isolated known larger loads from reading by turning off water heater and water pump breakers. No repair or change to outside panel yet. (Didn't feel like getting involved in working on the live outside panel in the rain). Spin had slowed some but still not good. Started to remove loads while observing spin. Found 2 circuits that by turning off would practically stop the meter spin. By returning either of the loads each had slight surge then balance with a slower but still a high rate of spin but did notice an odd effect only associated with these 2 circuits a mild continuous pulsing of the meter spin. (Seems these 2 circuits need further investigation with an amp meter.) Neither circuit was the one with burnt receptacle. Returned the known larger loads without the 2 suspect circuits, larger loads produced an expected increase in rotation of meter that leveled off once water pressure maxed and water heater achieved temperature. Then returned suspect circuits to the loads, still issue, high rotation and pulsing. Circuits are bathroom and master bedroom. Bedroom has a lot of electronics. Bathroom (I know a violation but it is there) has an added receptacle in another room that has a chest freezer plugged in.
Pulsing is puzzling, not sure if I'd see it on an amp meter. Not seeing any voltage pulse with voltmeter, might not be sensitive enough?
Any thoughts for further exploration?
Back ground: older Mobil home, someone rewired at some point.
Findings:
Main Disconnect: Voltage high, but normal, evenly distributed 249V LL 125/124LN. Both Neutral and Ground connections had improperly made or damage, cut off/missing parts of multi strand conductors, not all of conductor strands under pressure connector.
Inside panel: Voltages similar to outside panel. Found multiple circuits that had mixing of neutral and grounds on wrong buses. 2 circuits had neutral on the ground bus. (Yes panel N/G unbonded). Nearly every circuit termination was loose, some as much as 2 full turns to get listed torque. 2 circuits had visible heating of neutral wires (discoloration). One of which was related to a circuit HO had been using a portable heater that cord and plug had gotten very hot (reported by HO). Receptacle was very discolored. No breakers tripping. That circuit also was one that had neutral on the ground bus. HO reported that he later used the heater on a different circuit without the plug getting hot.
Pulled the discolored receptacle, found severe arcing evidence with partial meltdown, worst on the neutral terminal.
Without an amp meter was only able to semi check for draw by observation of meter spin. After repairs made to inside panel and bad receptacle, rechecked meter spin. Isolated known larger loads from reading by turning off water heater and water pump breakers. No repair or change to outside panel yet. (Didn't feel like getting involved in working on the live outside panel in the rain). Spin had slowed some but still not good. Started to remove loads while observing spin. Found 2 circuits that by turning off would practically stop the meter spin. By returning either of the loads each had slight surge then balance with a slower but still a high rate of spin but did notice an odd effect only associated with these 2 circuits a mild continuous pulsing of the meter spin. (Seems these 2 circuits need further investigation with an amp meter.) Neither circuit was the one with burnt receptacle. Returned the known larger loads without the 2 suspect circuits, larger loads produced an expected increase in rotation of meter that leveled off once water pressure maxed and water heater achieved temperature. Then returned suspect circuits to the loads, still issue, high rotation and pulsing. Circuits are bathroom and master bedroom. Bedroom has a lot of electronics. Bathroom (I know a violation but it is there) has an added receptacle in another room that has a chest freezer plugged in.
Pulsing is puzzling, not sure if I'd see it on an amp meter. Not seeing any voltage pulse with voltmeter, might not be sensitive enough?
Any thoughts for further exploration?
