Grounding suggestions

Charlie
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Grounding suggestions

Thu Sep 06, 2018 9:19 am

Hi

I am looking for suggestions on how I can make some good grounding for this design.
Have had a look at the forum post on grounding by sirhc but want to see if the experts here come up with the same design as what i think i should be doing to confirm I understand sirhcs forum post correctly.

After reading the forum post on grounding my reason for not being confident is there is a very long cable back to the fuseboard ground rod. The electrician didnt know much about radio grounding so was unhelpful.

My plan is to put a new ground rod at the cabinet, and connect it to the utility ground at the power point - but I dont know if the safety RCD will still work in the cabinet if thats the case?
I would then connect the metal cabinet and the netonix to the new ground rod.

Around the mast will be 3 more ground rods each connected to a leg of the mast (its a welded steel truss design) sunk into a cubic yard of concrete.
Then up the mast will be an AF11 which connects to the netonix using shielded cable with an ESD drain wire and shielded RJ45 plugs on each end.
The AF11 ground lug will also be attached to the steel tower.

Your suggestions are appreciated

https://i.imgur.com/qUZ9LQO.png


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sirhc
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Re: Grounding suggestions

Fri Sep 07, 2018 11:52 am

I have made extensive posts on grounding and all of the information I am about to tell you in abbreviated form is found in more detail in the following posts:

http://forum.netonix.com/viewtopic.php? ... 279#p19279
http://forum.netonix.com/viewtopic.php?f=30&t=1816
http://forum.netonix.com/viewtopic.php?f=30&t=188
http://forum.netonix.com/viewtopic.php? ... =30#p13447
http://forum.netonix.com/viewtopic.php?f=30&t=1429

Read the posts above but the basics are as follow:
99% of all WISP equipment damage is from ground current (I own a WISP)
I always add 1 or 2 “new” ground rods to older existing electrical services.
Tower ground rods must be bonded to electrical service ground rods HEAVY #2 wire.

In your picture you have created the classic 2 ground potential differential which will fry a lot of equipment.

Your service grounds are not bonded to the tower grounds so anytime you have more ground current than your service ground rods can handle before their path to ground through the service rods becomes less attractive to the tower ground rods then this current will flow through your switch then your cable then the radio to the tower then to the tower ground rods and POOF. Keep in mind you can get ground current through the ground and or neutral from your power company.

What you have shown in your picture is a BAD idea and will result in equipment loss.

Now what I would do but you should check your local regulation is what is outlined in this post:
http://forum.netonix.com/viewtopic.php? ... =30#p13447

I would also add EXTRA ground rods to the service panel, you want to make sure that your path to ground at the service panel is always better to the service ground rods than the tower ground rods.
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sirhc
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Re: Grounding suggestions

Fri Sep 07, 2018 11:56 am

Also if your using our SMART DC model such as WS-8-150-DC, WS-12-250-DC, WS-26-500-DC you should hook switch DIRECTLY battery bank and allow the Meanwell to simply charge the batteries.

If your powering the switch from the Meanwell then you should be using a 48V Meanwell and then use the WS-12-DC or WS-26-DC which is meant to be powered by a power supply.

I also talk about this OFTEN on here such as recently in this post: http://forum.netonix.com/viewtopic.php? ... ell#p25834
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Charlie
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Re: Grounding suggestions

Sat Sep 08, 2018 5:05 pm

The mean well PSU is indeed connected to the batteries which are connected to the netonix so if the mains power fails, the batteries run the netonix and we see a slow voltage drop over the following 36 hours before the netonix shuts off. Gives us heaps of time to get a generator on site or for mains to be restored.

With the grounding
1) install 3x ground rods for the tower and 1x for the data cabinet chassis, bonded together
2) Connect the netonix to the data cabinet ground
3) Disconnect the ground line going to the main utility board (this is the part I wasnt 100% sure about but you have clarified it for me thanks, post http://forum.netonix.com/download/file. ... &mode=view)
Instead connect the power outlet ground to the cabinet ground.
4) Connect the AF11 to the tower ground
5) A typical data cable distance would be 10 metres but the AF11 data cable will become 30 metres to increase the resistance

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Re: Grounding suggestions

Sat Sep 08, 2018 9:26 pm

I would still install 2 more NEW ground rods at service even though you are not bringing the ground as neutral is bonded to ground in service panel so ground can go to your box over the neutral.

I have considered but never done it yet but re bond bond neutral to ground at my box receptical that way neutral has direct access to tower earth grounds instead of going through equipment to tower.

Remember you just installed 3 NEW GOOD ground rods on tower so make sure service ground will never have a higher resistance to earth ground.
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