I have a customer with 480Y/277V transformer secondary and has installed Form 35S meter with 2CT's and no PT's. Meter is Elster A3 solid-state. The equipment end use is a PV inverter which is 3-wire, but the transformer is 4-wire, so I feel this should be 9S and not 35S. In addition they...
We have a 23kV 3-phase 3-wire system to be metered. The only available PT's are single bushing. Would it be accurate to install these in an un-grounded wye connection on the primary side and a grounded wye connection on the secondary side and use a three-phase 4-wire metering set-up? I know...
I have a service to a building with a conventional 120/028V, three-phase four wire service. There is a sub-panel being installed to a separate structure, and being fed overhead by quadraplex secondaries on poles (3-phase conductors and bare neutral supporting messenger).
The question is a...
I know it's commonly done and we specify it on larger projects. This is a small project and I was looking for a requirement in the NEC, because i don't believe there is one.
I have a NEC question. We are installing a new electrical service and panel (outdoors) for a lighting project. The service is single-120/240V and is grounding at the service entrance (outdoor cabinet, panelboard, utility meter) via 2 ground rods. A grounding conductor is run with each branch...
Can anyone tell me if there is a requirement in the 2008 NEC (because I can't find one) that requires a metal chain link fence to be grounded with an intentional ground rod, etc. under the following situation. There is an existing million+ gallon municipal water storage tank on a site. There...
Is anyone well enough versed in NFPA-70E to answer this? Is it required for HRC2 (8 cal/cm2) PPE that 2 layers be worn? Can a single layer of 11 cal such as a coverall be worn, or is some type of cotton undergarment or cotton layer required. My understanding was that HRC 2 needed 2 layers to...
Can anyone point me to the calculations need to set a transformer 87G differential ground relay? I have a customer with a nuisance trip and we believe it is set too low. I'm looking for a good explaination of the calculation. It's a delta-wye substation transformer 69kv-13.8kv, 18MVA.
Does anyone have any good articles, or links to basics of cathodic protection of ductile iron water pipe running perpendicular under a 115kV transmission overhead right of way??
Can anyone point me to a good link with the formulas or a spreadsheet that would be helpful in calculating transient, subtransient, etc. generator paramenters for induction generators. I have some work for a number of generators in the 100kW range and want to verify some vendor information and...
Does anyone have a good link for a paper, article, reference giving a simple discussion of utility overhead distribution protection, particularly related to transformer and line fusing on overhead systems. I'm looking for a good reference for the technically challenged.
