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Sparky's, I am looking into providing a waterproof raceway system that can be installed in the area of an industrial facility that falls below the protected flood elevation. The city chapter simply states waterproof methods shall be employed, but does not give any detailed descriptions as to...

Its a 480V power feed and some 120V control. The run is like 10-15 feet and not accessible to any vehicular traffic. I imagine it would be protected with some metal covering for foot traffic. This is in California, so the 2008 NEC applies, and I believe the 2007 NESC. This HAS to happen...

We are running temporary power and control cables to a piece of equipment. It has been proposed to run the cables on the ground for a couple weeks while permanent structural supports are constructed to route the raceway overhead. I looked i nthe code and wasn't able to find anything...

Does anyone see an issue with supplying a receptacle rated for 50A, 125/250V, 3-pole, 4-wire with a 50A 120/208, 3phase, 4-wire feeder?

I have a lighting panelboard and local control panel mounted in seperate NEMA 1 enclosures. These enclosures are located outdoors, where a NEMA 3R enclosure should have been provided. Does anyone know of any aftermarket kits that can be used to modify these NEMA 1 enclosures to a NEMA 3R...

I have 2 questions regarding approval of shop drawings for a project:   1) Our standard specifications call for all electrical equipment to be UL labeled. The contractor replied to my shop drawing request by stating that the breakers in a General Electric "AD" series panelboard were "UL Listed"...

I have a project that involves the connection of a stand alone high resistance grounding unit to a 12KV Generator Switchboard. I realize the intent of the HRGU is to limit fault currents and limit damage to equipment and personnel. I have little to no practical experience with these units and...

I wanted to know how to properly size electrical wiring for a distribution panel. Right now it is designed to be a 250A panel, and the overcurrent protection device is designed to be a 250A breaker. The trip setting of the breaker is currently designed to be 70A. The distribution panel...

Sorry dpc. I should have mentioned they were ungrounded wye transformers. Thanks for the info

Just seeking advice of the higher powers on this board. I have a client who has three ungrounded secondary unit substations. They want to connect high resistance grounding units to these substations. I understand the concept of these HRG units but I am not sure of how to physically wire them...

Once again I am coming to the fountain of knowledge to help me out here. I have been asked to wire a fire alarm system for a water treatment plant. The system will be composed of a fire alarm control panel, smoke detectors, manual pull stations and strobe lights. Does anyone know of the...

Hi guys. I am working on a project where our client has a 150HP motor and a 150HP VFD driving it. They want to replace the motor with a 200HP motor and also the corresponding drive. However, they want to do this one at a time. Either replace the drive first and then the motor or the motor...

Hi guys, I have a 150HP motor being controlled with a 200 HP VFD. The motor is rated for 3600 RPM. The client now wants to go with a 200 HP motor. Will the VFD need to be increased as well? I know the current ratings of VFD's are based on 4 pole 1800 RPM motors. How does having a 3600 RPM...

Hi everyone. Does anyone know of a table listing "typical" conduit fills for twisted shielded wiring? I know cable type and conduit type play a role but I wanted to get a ballpark number. Also, if there are any electricians out there and would like to inform me on the practical number of...

Thanks wbd. The client just has their picky preference. They listed a couple of manufacturers, but it was unclear as to the type of relay it was. I will now sound a little more eductaed tomorrow as to why (an instrumentation engineer) we approved the manufacturers submittal in the first place.

My company has always specified plug-in type utilizing rectangular blades. However the client we are working for doesn't like blade type contacts. What other alternatives are there? Thanks in advance

I know XHHW type conductors provide higher short circuit ratings and have overall better thermal characteristics than THHN conductors. What other advantages are there?

I work in the water/wastewater industry and I have a situation where an existing pullbox (not explosion proof) is mounted above grade of a wetwell. the wetwell is a classified area and above the wetwell is unclassified. There are conduits running from the pullbox box through the concrete roof...

My company specifies NEMA rated control relays for our projects. I presume this is because they are more durable. I do relaize they take up more space and are more costly, but is there any other benefit in specifying NEMA rated relays versus IEC?