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Lets say the main substation feeds a variety of stationary equipment. If so the Low side grouding of that substation can be solidly, ungrounded or resistance grouding. And you have a neutral run from that substation to the isolation substation or you do not have the neutral run. The isolation...

Find a local A/E firm who needs some incidental help at times. Then you can eventually become a "Professional Moonlighter" Jim

In the world of surface mining equipment, specifically large electric draglines and power shovels, the older units were MG set (motor generator) powered. And you could observe on the utility source bus, the voltage fluctuation due to the load swings as the dragline went through its motions. A...

In my experience engineering firms will not turn away a job even if they do not have experience in that area. For example, firms that have no medium voltage experience, will not turn away a substation job. If they can't or more often won't get someone who has the expertise, they will wing it...

I think it boils down to this. Low quality contractors and plants with poor configuration management will leave the cables in place. Of course, direct buried needs additional consideration. Jim

Sorry...Correction MSHA research group not OSHA Jim

In stripping (open pit) and UG ore mines the energy release from a thumper does not matter and a good deal of energy is needed to find a cable fault in MV cables with resistance grounded systems. In coal mines with the potential for methane gas it could be an issue but I don't believe that I saw...

I am registered in NJ and I just print my name and NJ License # at the end of my report. PERIOD Jim

From the management perspective.. as few as possible Jim

If you are smart enough, dumb enough or you have enough of a stomach to have stayed with a major company ( chemical, utility, oil and gas etc) for 30 years you could walk away with $2 M 401 K and almost a six figure per year defined benefit pension. A number of people in this group have never...

The worst reason for a female to go into engineering is because "they are good in math and science in High School" Where is the mechanical aptitude? Coding and software are better choices. All you have to do is ask yourself ..How many young girls ask for toy electric trains for Christmas...

Just as a comment, at our mining facility we had a number of large old 25 cycle transformers that were operating fine for many years on 60 Hz. Jim

Our EE consulting firm in Pa. has the same name as a fitness supply company in the SE USA and we had no problems, although they do want our domain name. JIM

It is common knowledge and often noted that IEEE 1584 does not apply to LV single phase systems and the results are conservative for example 240 volts three phase systems sourced from "small transformers" as well. Plant electrical personnel quickly loose confidence in arc flash studies (labels)...

It is also not uncommon practice in utilities, that if a CB is over-dutied and if the actual fault current is above the CB rating that the CB (as controlled by the CB relay) is blocked from tripping and the upstream CB operates. Assuming the upstream CB is rated for fault current. Jim

For HOT WORK in the CT revenue metering cabinet (on line side of customer main) Does your utility use IEEE 5184 calculations for this? Some members of our group feel, it give a too consrvative number (as expected with High side fuse as protective device only) since some research orgnizations...

A fellow accepted an offer as an engineering manager at a utlity and on the first day of work showed up and told the new employer he was going back to his former employer because they offered him a director position. He left after one hour on the job. The senior management at the utility was not...

For a 138KV fiber optic POTT scheme on network lines with a POTT instanteous O/C ground setting of about 300 amps, does your utility block the scheme during GOAB (group operated air break switching) on the lines? thanks JIM

You need to install the transformer to establish a new isolated system for your resistance grounded system. The utility multi wye grounded system cannot be used by just putting in a grounding resistor at your location. Jim

Our utility is looking at its practice of installing a CLF with a NEMA rated link (K) Cutout at 12.47KV O/H. We install them wherever the fault current exceeds 5KA sym. Our standards say our lowest rated cutouts are rated 6.2KA sym. Hearsay notes we install them due to dist. tranformer withstand...