It sounds like what is being said is not to ground the chassis of
various rigs. That is, all modern rigs, power supplies, Home wiring already have a common three prong plug and that should put everything to a common "ground" just by plugging it in. This excludes such historical anomalies like the early Astron power supplies that didn't have the chassis grounded and are fixed by running a wire from their chassis to the DC negative post. So the rod I have pounded in the ground outside the shack should be brought in the shack to connect to the antenna tuner only. Do I have that right? Because before I was running wire from the ground lugs of all the rigs, and computer chassis to a single copper pipe behind the gear and that pipe was then connected to the outside ground rod by another wire. I think I'm mixing old and new technology. Maybe a lot of this grounding lore came from yesteryear when three wire power cables and gear design was not the norm. If I wanted to check if I should attach some gear to that outside ground, would I put a meter between the outside ground wire and the rig chassis to see if I could measure anything. If so, what would I be looking for? Or put the meter between the chassis of two pieces of gear. If they all use three prong plugs, wouldn't they all be common? Thank you and 73, Paul, K7NHB _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
Paul and all,
There is a big difference between 'not required' and 'should not be done' - I trust I did not say it should not be done. It is OK to ground the K2 - I wanted only to point out that it is not necessary under the conditions stated. If the tuner is grounded and connected to the K2 by a coax cable, the enclosure of the K2 will be grounded to the tuner ground through the coax shield. If no safety ground is available through the coax, it is prudent to ground all metal enclosures that any body part could come in contact with. That is a safety ground situation, and has nothing to do with RF grounding - those are two different and separate considerations. If your K2 power supply negative terminal has a connection back to the AC utility ground, the chassis of the K2 will be safety grounded without the need for additional ground connections. For RF ground connections, these are better made to the tuner than the K2 chassis. Connections to a common ground in the shack should be made to a 'single point ground' rather than to a bus-bar type of ground. In other words, connect a wire from the (safety) ground point to a single connection point - the copper pipe along the back edge of the operating table is not the best solution - it works for a safety ground just fine, but can pick up noise and other artifacts by creating ground loops. There are at least 3 aspects that need to be considered for any grounding situation in the hamshack - 1) Safety, 2) Noise pickup and ground loops, and 3) RF ground effectiveness. If I have not been clear on this subject, please try again. 73, Don W3FPR > -----Original Message----- > It sounds like what is being said is not to ground the chassis of > various rigs. That is, all modern rigs, power supplies, Home wiring > already have a common three prong plug and that should put everything > to a common "ground" just by plugging it in. This excludes such > historical anomalies like the early Astron power supplies that didn't > have the chassis grounded and are fixed by running a wire from their > chassis to the DC negative post. > > So the rod I have pounded in the ground outside the shack should be > brought in the shack to connect to the antenna tuner only. Do I have > that right? > > Because before I was running wire from the ground lugs of all the > rigs, and computer chassis to a single copper pipe behind the gear > and that pipe was then connected to the outside ground rod by another > wire. > > I think I'm mixing old and new technology. Maybe a lot of this > grounding lore came from yesteryear when three wire power cables and > gear design was not the norm. > > If I wanted to check if I should attach some gear to that outside > ground, would I put a meter between the outside ground wire and the > rig chassis to see if I could measure anything. If so, what would I > be looking for? Or put the meter between the chassis of two pieces of > gear. If they all use three prong plugs, wouldn't they all be common? > > Thank you and 73, > Paul, K7NHB > _______________________________________________ > Elecraft mailing list > Post to: [hidden email] > You must be a subscriber to post to the list. > Subscriber Info (Addr. Change, sub, unsub etc.): > http://mailman.qth.net/mailman/listinfo/elecraft > > Help: http://mailman.qth.net/subscribers.htm > Elecraft web page: http://www.elecraft.com > -- > No virus found in this incoming message. > Checked by AVG Free Edition. > Version: 7.5.432 / Virus Database: 268.17.4/644 - Release Date: > 1/22/2007 7:30 AM > No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.5.432 / Virus Database: 268.17.4/644 - Release Date: 1/22/2007 7:30 AM _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
In reply to this post by k7nhb
I have quite a few power supplies and I think they are all isolated from
ground, ie the metal enclosure is safety grounded to the house mains supply (because they are Class 1 equipment in which the grounded chassis provides the main barrier to shock hazard), but both low voltage output terminals are floating which is provided by the mains transformer. Only plug top transformers, wall warts, power cubes and other plastic-enclosed power supplies have no mains earth connection in my experience. David G3UNA This excludes such > historical anomalies like the early Astron power supplies that didn't have > the chassis grounded _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
In reply to this post by k7nhb
Paul:
What you suggest, using a separate ground rod connected only to your antenna tuner, is both unsafe and a violation of the National Electrical Code. Section 250.50 of the 2005 Code (on page 70-101) states: "All grounding electrodes (read ground rods) that are present at each building or structure served shall be bonded together to form the grounding electrode system." If two or more ground rods exist and are not connected together (bonded) electrically a lethal voltage can exist between the two in the event of a nearby lightning strike. 73, Henry. WA2IRQ ---------------------------- Henry W. Ott Henry Ott Consultants www.hottconsultants.com On Jan 22, 2007, at 10:28 PM, Paul wrote: > It sounds like what is being said is not to ground the chassis of > various rigs. That is, all modern rigs, power supplies, Home wiring > already have a common three prong plug and that should put everything > to a common "ground" just by plugging it in. This excludes such > historical anomalies like the early Astron power supplies that didn't > have the chassis grounded and are fixed by running a wire from their > chassis to the DC negative post. > > So the rod I have pounded in the ground outside the shack should be > brought in the shack to connect to the antenna tuner only. Do I have > that right? > > Because before I was running wire from the ground lugs of all the > rigs, and computer chassis to a single copper pipe behind the gear and > that pipe was then connected to the outside ground rod by another > wire. > > I think I'm mixing old and new technology. Maybe a lot of this > grounding lore came from yesteryear when three wire power cables and > gear design was not the norm. > > If I wanted to check if I should attach some gear to that outside > ground, would I put a meter between the outside ground wire and the > rig chassis to see if I could measure anything. If so, what would I be > looking for? Or put the meter between the chassis of two pieces of > gear. If they all use three prong plugs, wouldn't they all be common? > > Thank you and 73, > Paul, K7NHB > _______________________________________________ > Elecraft mailing list > Post to: [hidden email] > You must be a subscriber to post to the list. > Subscriber Info (Addr. Change, sub, unsub etc.): > http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/subscribers.htm > Elecraft web page: http://www.elecraft.com > > Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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