On Mon, Aug 30, 2021 at 1:57 PM Tom Beecher <beec...@beecher.cc> wrote:
> There are usually redundancies built-in when it comes to safety. i.e. >> what's the point of installing grounds on the upstream side if you have the >> switch open? If the lines are de-energized, why wear gloves? If you're >> doing all that, why carry an AED? >> > > My uncle was a high tension lineman for much of his career. He was > frequently on response teams that went all over the country helping restore > power after severe weather or natural disasters. > > There are not 'usually' redundancies. There are ALWAYS redundancies. > Yup - and even with this, "an average of 45 linemen a year loses their lives in the line of duty, leaving families who depend on them." -- https://fallenlinemen.org/frequently-asked-questions/ The original point remains: "Reminder: Never connect a generator to home wiring without transfer switch". > Because in that world, especially doing restorations, there are rarely > opportunities to learn from a mistake. > Indeed. W > > > On Mon, Aug 30, 2021 at 1:48 PM Aaron C. de Bruyn via NANOG < > nanog@nanog.org> wrote: > >> During the February 2021 storm that swept through the US, power got >> knocked out on my rural street due to a tree coming down and taking out a >> pole. >> >> While they were waiting for a few more trucks to arrive with a >> replacement pole, I got to ask them a few questions. They said it's >> standard practice for them to ground on both sides exactly for the reason >> that someone might accidentally connect a generator. They open the nearest >> switch on the upstream side, test to make sure the line is dead, install >> grounds on all the wires, then test the downstream side and attach grounds >> to all the wires, effectively making the work zone an isolated segment. >> >> I doubt it's "if you follow every step perfectly at all times and never >> make a mistake". >> There are usually redundancies built-in when it comes to safety. i.e. >> what's the point of installing grounds on the upstream side if you have the >> switch open? If the lines are de-energized, why wear gloves? If you're >> doing all that, why carry an AED? >> >> -A >> >> On Mon, Aug 30, 2021 at 10:19 AM Warren Kumari <war...@kumari.net> wrote: >> >>> >>> >>> On Mon, Aug 30, 2021 at 12:47 PM Aaron C. de Bruyn via NANOG < >>> nanog@nanog.org> wrote: >>> >>>> I've been following the thread. >>>> If I'm dumb enough to back feed through the transformer into the >>>> downstream side of the downed line, how is it going to be a problem if >>>> linemen are grounding the phases on *both sides* of the work area. >>>> >>> >>> I suspect that there is a non-zero amount of "in an ideal, perfect >>> world, when all of the wires are simply lines on a piece of paper, and you >>> can look at them from the comfort of your office chair, this is easy" - >>> but, in the real world, linesmen are rushing about and trying to get the >>> lights back on, cut through the big ash tree that is wedged between the oak >>> and the pole, etc. Even the nice idea of "well, just take the conductos and >>> tie 'em to ground" means that you need to go trudging through hedges and >>> vegetation and tree limbs and lions and tigers and bears, often while it is >>> pissing down with rain or baking hot. >>> >>> I guess I'm missing how we've moved from the "some people are putting >>> their lives on the line, let's try to make their life less dangerous" into >>> a "weeeeell... if they simply followed these set of steps perfectly at all >>> times, and never made a mistake they'd be fine." >>> This is NANOG -- I'm sure that we've all followed a set of steps >>> perfectly and still managed to redistribute BGP into the IGP, or apply an >>> ACL and lock ourselves out of a box, or types "show run" and watched the >>> router randomly reboot. Now consider this, but with the added drama of >>> potentially ending up dead... >>> >>> W >>> >>> >>>> That's what Ben seemed to be implying. >>>> >>>> -A >>>> >>>> On Mon, Aug 30, 2021 at 9:09 AM Mel Beckman <m...@beckman.org> wrote: >>>> >>>>> Aaron, >>>>> >>>>> If you read back in this thread (using the NANOG mailing list >>>>> archive), you’ll find this has been explained in great detail. In a >>>>> nutshell, phase grounding won’t help if a generator is energized from the >>>>> customer end, and this technique was discontinued in the 1970s due to the >>>>> many deaths that resulted. >>>>> >>>>> -mel >>>>> >>>>> On Aug 30, 2021, at 9:02 AM, Aaron C. de Bruyn via NANOG < >>>>> nanog@nanog.org> wrote: >>>>> >>>>> >>>>> On Mon, Aug 30, 2021 at 7:35 AM Lady Benjamin Cannon of Glencoe, ASCE < >>>>> l...@6by7.net> wrote: >>>>> >>>>>> Yes, this is a real and dangerous problem. Today. Even with >>>>>> grounding I’m afraid. Source: I’ve been working in an engineering >>>>>> capacity >>>>>> for 27 years and I have the license you’d need to build a nuclear power >>>>>> plant. >>>>>> >>>>> >>>>> Would you care to educate me on this? >>>>> If you ground the phases on both sides of the work-site, how are you >>>>> going to end up being a better path to ground? >>>>> >>>>> -A >>>>> >>>>> >>> >>> -- >>> The computing scientist’s main challenge is not to get confused by the >>> complexities of his own making. >>> -- E. W. Dijkstra >>> >> -- The computing scientist’s main challenge is not to get confused by the complexities of his own making. -- E. W. Dijkstra
