More IMPORTANT Grounding Stuff - WIND STATIC DAMAGE

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sirhc
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More IMPORTANT Grounding Stuff - WIND STATIC DAMAGE

Sun Jan 24, 2016 2:59 pm

We have a tower which is a 170'+/- Mushroom Water tank in Leola.

We shared this tank top with Sprint for many years. They installed an excellent HALO grounding system which we tapped off of. We had never lost a radio on this tank in well over 10 years until this past year.

This past summer Sprint left the tank and hired a salvage company to remove the equipment and wire/coax.

They were supposed to leave the grounding system intact but obviously the 200' of #1 Copper ground wire that ran from the lower ground bus to the upper ground bus was just too tempting for them to take for salvage.

Shortly after they left the tower we lost our first radio in 4 years which I made a post about on this forums last spring/summer but we did not understand completely what was going on at that time.

When a storm came through we lost an AF24 and it also fried the current sensors on Port #1 and Port #2 feeding the (2) AF24 radios which are located right next to the original ground bus bar. The switch continued to function just the current sensors were blown.

At first we were completely ignorant that the #1 ground wire had been removed so we replaced the AF24 and the WS-24-400A.

A couple months later we lost the current sensors again on Port #1 and #2 of the switch so we took a closer look and this is when we discovered the #1 ground wire was missing so my crew quickly ran a new #2 green up the inside of the tank as that is where our wires/conduit runs whereas Sprint ran their wires up the outside of the tank in a cable trough.

A couple months later a heavy rain event occurred and we once again lost the current sensors on Ports #1 and #2 so again we replaced the switch and decided that in the spring time we would redo the grounding thinking the heavy rain was gone until spring.

On Friday night the BIG snow storm and high winds rolled into our area and the AF24 units were going down losing Ethernet connectivity and forcing our service to roll over to our backup MIMOSA link that comes into another tower. The first thing I noticed was the current sensors once again were blown on Ports #1 and #2 on the switch and the AF24 Ethernet links had down graded to 10 Mbps and were getting tons of errors forcing OSPF to fail over to our backup link.

I was able to restore 1G connections by powering off ports #1 and #2 and then power them back up and 1G connectivity was restored but when the HIGH winds were blowing the links would start getting errors and eventually step down to 10 Mbps forcing the traffic to once again fail over to the backup MIMOSA link on another tower.

Eventually I got tired of fighting the wind and restarting the links and simply shut those links off until the winds stopped the next morning (Sunday/Today).

My assumption is that the high winds and snow was causing a static charge that saw a shorter/better path of less resistance to ground via the Ethernet cable instead of the intended ground wires. This charge was causing Ethernet errors and fried the current sensors on the switch ports #1 and #2.

So tomorrow (Monday) we are starting the process of adding a new #2 green that goes from the original lower ground bus to the original upper ground bus next to the AF24 radios. We will also make sure there is a sufficient Ethernet service loop on the AF24 radios to insure that the Ethernet path (cable length) from the radio to the grounding system is longer than the intended grounding path (cable length).

It is imperative that the intended grounding path is shorter and of much lower resistance than the Ethernet cable provides. This was a perfect example how high winds can cause static charges to build up and interfere with Ethernet communications and also damage the current sensors or could even damage an Ethernet port in your devices and or switches and this type of damage is not covered under warranty.

I also noticed last night during the storm that we were experiencing Ethernet errors but no damage on other ports and on other tower switches which would indicate that the grounding system was working to prevent damage but probably not good enough to prevent Ethernet errors from showing up on interfaces in the high winds. Since the storm and winds have passed I have cleared the errors and have not seen any return on any of the towers.

People should also review this post: viewtopic.php?f=17&t=1786&start=30#p13447

IMPORTANT FACTORS:
Ground wire runs should be shorter from antennas to ground rods then Ethernet cable run from radio to ground rods

Ground wire should go through as few of connections/splices as possible because these splices/connections insert resistance and you want the intended ground wire to be of as least resistance as possible.

Use Ethernet service loops at radios to increase Ethernet cable length/resistance to insure it is a longer path than intended ground wire path.

THIS WAS THE ORIGINAL GOOD GROUNDING
BEFORE.png


THIS WAS WHAT SPRINT LEFT US WHEN THEY LEFT
AFTER.png

THIS WAS OUR FIRST HURRIED FIX WHICH FAILED
HURRIED.png

THIS IS OUR NEXT ATTEMPT - SHOULD WORK
NEXT.png

THIS IS THE DAMAGE TO THE WS-24-400A SUFFERED LAST NIGHT - NOT COVERED UNDER WARRANTY
Damaged.png

Damage 2.png


THIS IS THE TOWER LAST 4th OF JULY
Quarry Road.jpeg
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Re: More IMPORTANT Grounding Stuff - WIND STATIC DAMAGE

Wed Jan 27, 2016 1:18 am

Good info. Thanks Chris.

Oddly, we have had to go back to cable fastening 101. Three times now the wind has gotten up here, causing the cables to move and drop links on AF5X radios... annoying but easy fix.

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Re: More IMPORTANT Grounding Stuff - WIND STATIC DAMAGE

Wed Jan 27, 2016 10:09 am

That tower looks like a HUGE Tesla Coil!!
Mike A - www.iwisp.gr

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Re: More IMPORTANT Grounding Stuff - WIND STATIC DAMAGE

Wed Jan 27, 2016 10:27 am

Mikea wrote:That tower looks like a HUGE Tesla Coil!!


What? Who said anything about us taping Magnetic Potential Energy to provide FREE energy for our town once talked about by Mr. Tesla. I did not say that, no need to send in the fossil energy folks. Nothing to see here folks, move along... :leave:
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Re: More IMPORTANT Grounding Stuff - WIND STATIC DAMAGE

Wed Jan 27, 2016 12:51 pm

:rofl4: :rofl4:

I ll have to admit that this is more like an oil reservoir and has nothing to do with any kind of greenish energy! Just pure V8 here :D Sweeping
Mike A - www.iwisp.gr

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Re: More IMPORTANT Grounding Stuff - WIND STATIC DAMAGE

Wed Jan 27, 2016 2:28 pm

It is green energy storage. What goes up, must come down. The energy used to push it up can be recovered when reversed.

They do similar in reverse with deep water balloons.
http://www.thestar.com/news/gta/2015/11 ... tario.html

They also want to use underground salt caves to store natural gas. Natural gas is already stored underground... well... ummm.... naturally. Just don't extract it until you need it.
https://www.eia.gov/naturalgas/storage/basics/

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Re: More IMPORTANT Grounding Stuff - WIND STATIC DAMAGE

Fri Apr 08, 2016 7:19 pm

we use tall buildings and natural high spots and haven't lost a radio is 3 years despite not really having any grounding other that the drain wire of the cabling.

Have we just been really lucky or is it the lack of a metal tower?

:cheers:

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Re: More IMPORTANT Grounding Stuff - WIND STATIC DAMAGE

Fri Apr 08, 2016 7:36 pm

STBAZ wrote:we use tall buildings and natural high spots and haven't lost a radio is 3 years despite not really having any grounding other that the drain wire of the cabling.

Have we just been really lucky or is it the lack of a metal tower?

:cheers:


The biggest problem is when you have a metal tower with its own grounding system that is not bonded to the service ground. At this point you have two differnt ground potentials and they will try to equalize across your Ethernet cable. But the worst thing happens when one ground shifts due to rain or what have you and once again that Ethernet cable is the path the current will take to equalize.

If you have a static charge on the antennas and or tower and the best path to ground with the least resistance is the Ethernet cable - POP

I think the posts are pretty self explanatory, people can make excuses as to why they do not need to put in proper grounding systems but those are the people who also cry when they lose equipment.

I think my posts speak for themselves?

In your situation I would run a #6 or preferably #2 Green between where your switch is and where your radios are and put a ground bus on each end. Then run a #6 from the ground bus to each antenna mount and to any radios that have ground lugs. Down in your cabinet I would connect that ground bus to any equipment with a ground lug and to the Electrical service ground. Next I would make sure that I had a service loop at the radio on the Ethernet cable to insure it is a 10% longer run than the ground run.

You want all equipment at a site to be on the same ground potential and make sure that the shortest path between any 2 devices is NOT the Ethernet cable.

Pretty simple concept.
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Re: More IMPORTANT Grounding Stuff - WIND STATIC DAMAGE

Fri Apr 08, 2016 8:16 pm

Very interesting reading. Three related questions though:
1. If proper grounding is hard to find, still running copper between antenna (and its board if embedded) and the next router / switch is a good idea? Just to make sure any potential differences between devices are levelled over the copper instead of the ethernet?
I live in a desert like environment with improper build houses. Some houses have ample ground system in place and during the end of the summer the ground is powder dry up to several meters deep.... The biggest earth mass I can find is the house wiring itself. Even water connections won't help since all made in pvc....
Call it poor design but since we use several AP spots on top of houses this way it is some fact of our live. No proper earth....

2. What is best to use? FTP or UTP? Most outdoor ethernet cable comes in ftp form so we use them and we fit shielded connectors. But some actually tell me that if there might be an ESD issue, I would be better off using non shielded utp cable? (Or just shielded ftp but no shield terminators on both ends, just plastic ones....? Against all theoretical books...?)

3. Does all that proper grounding to create shortest ground path to real ground not enhance the risk of lightning strikes? As many small WISP we really can't afford to protect all our installations with full lightning protection. The cost would outrun many times the cost of an occasional radio that we might loose. (Lost 2 CPE's by lightning in 14 years.. so not so bad at all.... Nowhere we have proper lighting protection and many sides have no proper ground. CPE by default are never grounded....


From a real prof industry point of view this might all look very stupid or out of the question practises but I'll bet many small WISPs that try to earn couple of bugs don't have the resources to spend big time on proper ground and lightning protection. So its more a money-to-common sense-to-risk assessment balancing.....
But any practical advices will be taken in account and be much appreciated...... :thumbsup:

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Re: More IMPORTANT Grounding Stuff - WIND STATIC DAMAGE

Sat Apr 09, 2016 3:10 pm

WirelessRudy wrote:From a real prof industry point of view this might all look very stupid or out of the question practises but I'll bet many small WISPs that try to earn couple of buks don't have the resources to spend big time on proper ground and lightning protection. So its more a money-to-common sense-to-risk assessment balancing.....
But any practical advices will be taken in account and be much appreciated...... :thumbsup:


Proper grounding does not have to cost a lot.

You can shop around and buy a spool of #2 Green at Home Depot for $166

Grounding and other tower materials can be found at
SitePro1However
#2 Green Ground Wire 6 AWG is cheaper at Home Depot


For an average 200' tower a WISP should be able to do proper grounding for $500 to $1000.
Or they can replace switches, routers, and radios that take damage which is expensive and not covered under warranty PLUS suffer customer losses from outages. :ak:

There really is not reason NOT to implement proper grounding.

These 2 posts provide all the information they need to do proper grounding.
viewtopic.php?f=30&t=188
viewtopic.php?f=30&t=1429

But when I get switches back on RMA that look like this I am not going to warranty them, we will repair them which most times is a NEW board @ $75 to $250 depending on the model.

RMA 126 - Destroyed.png

RMA 125 - WOW.png

RMA 108 - U98 destroyed.png


It is the fact that I see what I see in the RMAs that I am trying real hard to educate WISPs on the importance of a GOOD grounding system and how to put it in. It is not super expensive and once you have it in you can start enjoying those lightening and heavy rain or wind storms again.....well at least they are not as scary to me anymore but I do still cringe.
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