I have two new dual voltage, 9 lead, delta motors where leads 1, 2 and 3 are one wire size larger than the other 6 leads. One motor is a 15 hp with #12s and #10s and the other is a 25 hp with #10s and #8s. I don't think I have ever seen this before and I don't see any electrical reason to do...
I recently worked on clearing a ground fault on a 1200 amp 3 phase 480 volt service. After the ground fault was cleared I had 490 volts phase to phase and about 900 volts phase to ground on all three phases. It was discovered that when the utility built the transformer bank they did not...
When you make a code compliant installation of a service in a building that is served by an interconnected metal underground water piping system, some of the current that should be flowing on the grounded conductor will flow on the parallel path provided by the water pipe. Is this a serious...
I'm going to be installing a large DC motor that will require that the armature leads be installed in parallel from the drive to the motor. Can I install the 3 positive leads in one conduit and the 3 negative leads in the second conduit? The conduits will be rigid steel. I know that you can't...
I have been getting conflicting information on checking or re-torqueing a wire termination. I have been taught that this should never be done due to the cold flow or relaxation that occurs over time. This relaxation has been accounted for in the original torque specification. If you check the...
