On 08/07/2017 03:21 PM, James Knott wrote:
John Andersen wrote
Neutral is tied to Ground almost everywhere in the US, if not on your house then on the next nearest pole or power pedestal.
Ummm... Neutral is *ALWAYS* tied to ground at the power entrance. Other services are likewise bonded to the same ground point.
We said the same thing, BUT, I was REALLY pointing out (somewhat off topic) is that it is not uncommon in certain geological regions for there to be a difference between grounded neutral and actual ground simply because of a loss of ground-conductivity. In some systems (cable tv systems often), this leads to the entire cable plant floating above ground by a measurable (but not dangerous) volt or two, which plays havoc with reception. This was common in some parts of alaska, probably due to inconsistant grounding practices of the installers and the rush job they did when installing. But more to the point there are differences in grounding practices in some parts of the world: https://en.wikipedia.org/wiki/Ground_and_neutral#Grounding_systems TN-C and TN-S. Quoting above....
In the TN-C system, a common conductor provides both the neutral and protective grounding. The neutral conductor is connected to earth ground at the point of supply, and equipment cases are connected to the neutral. The danger exists that a broken neutral connection will allow all the equipment cases to rise to a dangerous voltage if any leakage or insulation fault exists in any equipment. This can be mitigated with special cables but the cost is then higher.
https://en.wikipedia.org/wiki/Earthing_system#IEC_terminology Usually you won't have any problem in the same data center. But as common office space get pressed into service as mini-data-centers, all bets are off. **In any event, if all the SCSI devices are plugged into the same wall socket or UPS there should not be any grounding issues.** There's a lot of mythology involved here as well: http://www.eetimes.com/document.asp?doc_id=1272972 -- After all is said and done, more is said than done. -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse+owner@opensuse.org