I think it's important to differentiate between electrical safety grounding and
lightning protection grounding because I think that is some of the confusion.
The two are not the same and different techniques are used in the application
of both. The electrical safety grounding rules are outlined in the NEC or
NFPA...but a proper electrical safety grounding system is a lousy lightning
protection system in most all cases. I noticed different grounding techniques
mentioned in the recent posts and they are a mixture of both. The station
example with the ground buss across the station console is most likely a
lightning protection application. The thing to keep in mind is to not
compromise electrical safety grounding in applying a lightning protection
scheme. Any lightning protection grounding system has to be bonded to the
electrical safety ground.
Cecil
K5DL
Sent from my iPad
On Sep 5, 2012, at 7:26 PM, Jim Brown <k9yc@audiosystemsgroup.com> wrote:
> On 9/5/2012 11:45 AM, Richards wrote:
>>
>>
>> Is this notion of bonding the V- to chassis in any way
>> related one could get shocked when touching the
>> chassis of an old Halicrafters tube sets?
>
> NO. But it IS caused when the GREEN WIRE is not properly bonded to the
> chassis, or when every chassis is not bonded to every other chassis and to
> ground. That GREEN WIRE IS GROUND, coming all the way from the breaker panel
> that feeds it. It's not a great RF ground, but it's a great SAFETY ground,
> and it is required by LAW in virtually every developed country. .
>
>>
>>
>> Observation:
>>
>> [I am still taking Electronics 101. But I remember the
>> time I got stung touching a hot chassis.}
>>
>> I would have thought a serious concept like grounding stuff would be so
>> important, it would be codified in a consistent set of rules even rookie
>> operators could apply and follow.
>
> It is, that "codification is the National Electric Code (NEC), and there is
> excellent material on this in recent editions of the ARRL Handbook.
>
>> Also, I would have thought the product manufacturers would be on one track,
>> with consistent instructions and consistency in the gear.
>
> The Astrons are DESIGNED correctly, but the PAINT is a manufacturing defect.
>
>>
>> But... NOOooo... that would be too easy! Consider, f'rinstance, this
>> topic of grounding power supply chassis. Nearly every rig needs a power
>> supply. Nearly every instruction manual says to ground each chassis to the
>> other ones, and to a stick in the mud. Even TenTec says to do that in my
>> transceiver user manual.
>>
>> OK... but then there is no ground lug on my TT 963 power supply. There is no
>> ground lug on 2 of my Astron power supplies.
>
> Well, there is, it's called the GREEN WIRE.
>
>> There is no ground lug on my TT receiver, and similarly no ground lug on
>> most of of my station accessories. And yet they all have AC or DC power.
>
> That's unusual. Most ham rigs I've seen have a ground lug.
>
>> Some guys say to wire the green wire to the chassis (which I somehow get)
>> but then other guys debate wiring the negative to chassis (which I don't
>> get, because I remember the sting of my old radio years ago). Some advocate
>> adding a ground lug to the power supply chassis - but the manufacturer did
>> not.
>>
>> And then TenTec service told me not to ground ANY of it unless I have a
>> specific problem to solve, which just a little contradicts what it says in
>> the instruction manual. Some guys have grounding bars across the back of
>> their desks. Others don't have anything. One would have thought, if all
>> these things are supposed to work together, there would be a common way of
>> doing it.
>
> That's why it's important to develop an effective BS filter. One of the best
> BS filters is EDUCATION. You're an attorney, as I recall, so I'll bet you've
> got a pretty good BS filter in that field, and to some extent with respect
> human nature and reading people. But until you develop your technical BS
> filter (see education, above) you're always going to be wondering who to
> believe.
>
>> Heck, now you guys say even Astron is inconsistent over time - and on the
>> same model supply, too. And now we are all wrangling over different rules
>> and approaches to it.
>
> The only RULES here are that, BY LAW, EVERY exposed chassis MUST be bonded to
> ground, if it's connected to the power line, it MUST be bonded to the Green
> Wire, and ALL grounds MUST BE bonded together. And for good RF performance,
> and to minimize hum and buzz, those bonds should be short fat copper.
>
> FWIW, I've written extensively about all of this stuff in tutorials that are
> on my website. All you have to do is study them.
>
> 73, Jim K9YC
> _______________________________________________
> TenTec mailing list
> TenTec@contesting.com
> http://lists.contesting.com/mailman/listinfo/tentec
_______________________________________________
TenTec mailing list
TenTec@contesting.com
http://lists.contesting.com/mailman/listinfo/tentec
|