Good question, I"ll have to check. On Wed, Sep 30, 2015 at 11:14 AM, Chuck McCown <ch...@wbmfg.com> wrote:
> The surge suppressors will still block transverse impulses but they will > not be able to recognize longitudinal (common mode) impulses without a > ground. Isn’t there a lightening rod or obstruction light up there that > you could ground to? > > *From:* Josh Baird <joshba...@gmail.com> > *Sent:* Wednesday, September 30, 2015 9:11 AM > *To:* af@afmug.com > *Subject:* Re: [AFMUG] Grounding strategies for water tanks > > Ok, so I have a little more information now. > > The city that owns these tanks forbids us to mount /anything/ directly to > the tank it's self. They also forbid us to scrape any paint to ground > anything. There is a thick rubber guard that covers the rails where the > antennas are mounted. The antennas are mounted on top of this rubber guard > (not directly to the metal). The antennas will have short CAT-5 runs to a > tower-top box, and then fiber/DC down the tower to our battery/charger. > > In this scenario, should we just try to make sure everything is isolated > from the tank as much as possible and float the ground? I was planning on > using GigEAPC-HV surge protectors at the top for all of the radios. If the > surge protectors are not grounded, is there any point in even using them > seeing that they won't have any ground to discharge the surge to? Will > they provide any benefit at all? I was also planning on using DC surge > suppressors between the DC cable that runs up the tank (one at the bottom, > one at the top). Again, will they be useful at all if we are floating the > ground? > > Thanks, > > Josh > > On Mon, Sep 28, 2015 at 12:46 PM, Mark Radabaugh <m...@amplex.net> wrote: > >> We have had pretty good luck with that style of tank. >> >> As to the question - we bonded the #6 to the steel railing and mounting >> points at the top, the ladders on the way down, the tank ‘waist’ railing, >> the inside ladder, the electrical ground, our cabinet and the associated >> surge suppressors, and the steel water line entering the ground. >> >> Mark >> >> On Sep 28, 2015, at 10:38 AM, Josh Baird <joshba...@gmail.com> wrote: >> >> The tanks are like these: >> >> http://www.mscivilengineers.com/images/12.jpg >> >> I'm not sure what the bottom looks like, though. I'll have to go out and >> check them. So, you ran #6 all the way down the tank and bonded it inside >> of your enclosure/cabinet/whatever? >> >> On Mon, Sep 28, 2015 at 10:31 AM, Mark Radabaugh <m...@amplex.net> wrote: >> >>> What type of tank? >>> >>> The hydropillar and waterspherioid style are generally well grounded. >>> >>> I have seen some of the steel tank on a concrete pedestal style where >>> the tank is not directly grounded to the pedestal but has a ‘spark gap’ >>> between the tank and the base. I’m not sure if the purpose was to >>> distribute the strike around the tank into the rebar in the column, or if >>> it was an attempt to isolate the steel for corrosion reasons. The tank we >>> are on like that consistently has the most lightning damage. I eventually >>> ran a #6 copper from the top of the tank to the railing and down inside to >>> tie everything together. It’s improved the situation considerably but it’s >>> still not perfect. >>> >>> Mark Radabaugh >>> Amplex >>> 27800 Lemoyne, Ste F >>> Millbury, OH 43447 >>> 419-837-5015 x1021 >>> m...@amplex.net >>> >>> On Sep 28, 2015, at 10:19 AM, Adam Moffett <dmmoff...@gmail.com> wrote: >>> >>> Yeah, I would think the tank itself is ground. >>> >>> On 9/28/2015 10:16 AM, Chuck McCown wrote: >>> >>> Common point grounding at the power ground would be the NEC answer. >>> >>> I would do that for power grounds and surge suppressor grounds because >>> most surges come via the power lines. >>> >>> For antenna mounting grounds etc, I would make sure they were in good >>> contact (bonded, perhaps with a separate bonding wire) to the tank or >>> railing or whatever metal structure you are attaching to. >>> >>> *From:* Josh Baird <joshba...@gmail.com> >>> *Sent:* Monday, September 28, 2015 8:13 AM >>> *To:* af@afmug.com >>> *Subject:* [AFMUG] Grounding strategies for water tanks >>> >>> We are going to be installing on several water tanks that do not have >>> any other carriers on them. I'm assuming there is probably not a ground >>> ring or system in place at these sites. The electrical service is likely >>> grounded independently using a ground rod at the pole. >>> >>> These sites will have batteries and a charger at the bottom and fiber/DC >>> up the tower. Admittingly, I'm fairly (ok, very) stupid when it comes to >>> grounding systems. I understand that everything *should* be bonded >>> together. However, if the tank it's self doesn't have a sufficient >>> grounding system already in place, what is the best strategy here? >>> >>> Thanks, >>> >>> Josh >>> >>> >>> >>> >>> >>> >> >> >> >> > >
