I have an unusual situation. The local power company is of no help. They insist the building must be wired wrong. They have conceded that the incoming power lines from the transformer would be their responsibility.
The problem:
Transformer is 150 feet from panel. Feeders are 1/0 alluminum in steel conduit. panel is 200 amp, 240 volt, 3phase, 4 wire.
Connected loads: (2) 3 phase motors, 208 volt. Lighting, 120volt, and several receptacle circuits used for compressors and power tools.
When 3 phase motors are on by themselves, everything is okay, voltage drop tollerable.
When lighting on (same leg) very little amperage, minimal 3-4% voltage drop, 2 amp maximum draw.
When receptacle with heavy compressor or pump on, 60% voltage drop, causing high amperage and breaker to trip.
Have tried every possible test, moved receptacle circuits to different phase legs, only receptacle breakers on, only lighting on only 3 phase on.
Our determination is it has to be the nuetral is comprimised between transformer and panel (transformer powers another building with no apparent voltage drop, so we have determined that the incomming nuetral must be in tact).
Power company says they are not convinced. They think the load side might be causing the problem. We have tested all breakers off except one dedicated receptacle circuit. Only nuetral loads cause voltage drop. What else could cause voltage drop?
One other confusing note, the only load side conduit that goes through the concrete (into the ground) has only one circuit in it, when any circuit is live had arcing at the panel connector. We removed the circuit wiring that is running through the conduit in question, including the nuetral, still had arching when other circuits are on. This is why the power company says it has to be load side wiring?
The problem:
Transformer is 150 feet from panel. Feeders are 1/0 alluminum in steel conduit. panel is 200 amp, 240 volt, 3phase, 4 wire.
Connected loads: (2) 3 phase motors, 208 volt. Lighting, 120volt, and several receptacle circuits used for compressors and power tools.
When 3 phase motors are on by themselves, everything is okay, voltage drop tollerable.
When lighting on (same leg) very little amperage, minimal 3-4% voltage drop, 2 amp maximum draw.
When receptacle with heavy compressor or pump on, 60% voltage drop, causing high amperage and breaker to trip.
Have tried every possible test, moved receptacle circuits to different phase legs, only receptacle breakers on, only lighting on only 3 phase on.
Our determination is it has to be the nuetral is comprimised between transformer and panel (transformer powers another building with no apparent voltage drop, so we have determined that the incomming nuetral must be in tact).
Power company says they are not convinced. They think the load side might be causing the problem. We have tested all breakers off except one dedicated receptacle circuit. Only nuetral loads cause voltage drop. What else could cause voltage drop?
One other confusing note, the only load side conduit that goes through the concrete (into the ground) has only one circuit in it, when any circuit is live had arcing at the panel connector. We removed the circuit wiring that is running through the conduit in question, including the nuetral, still had arching when other circuits are on. This is why the power company says it has to be load side wiring?
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