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Wattage sensors blown?

Posted: Tue Oct 02, 2018 9:28 am
by gaspensonace
We had a storm roll by yesterday and our switch (WS-26-400-IDC) rebooted. A couple of ports are now showing the wrong wattage output. I'm guessing the sensors were blown on these ports but yet they are still functioning normally. My guess is ESD. Thoughts? Haven't been down to look at grounding issues at the site.

Re: Wattage sensors blown?

Posted: Tue Oct 02, 2018 9:41 am
by sirhc
NOT caused by ESD.

Electro Static DIscharge would have damaged your radio before the switch.

This is caused by GROUND CURRENT from poor grounding.

Add additional electrical service grounds to existing service grounds.

Make sure electrical service grounds are BONDED to tower ground rods with HEAVY #2 wire.

You can RMA the unit and have it repaired but if you do not fix your grounding it will occur again.

It is not the lightning that causes this damage but rather the water that runs down around electrical service ground rods and raises their resistance to Earth Ground so for that moment all the excess current on the service panel sees the tower ground rods which are normally newer and better as a better path to Earth Ground so all that current goes through your switch through your Ethernet cable to the radio to the tower to get to the tower ground rods.

99% of all WISP equipment damage is from ground current (I own a WISP)

Here are some good posts on grounding:
viewtopic.php?f=30&t=2786&p=19279#p19279
viewtopic.php?f=30&t=1816
viewtopic.php?f=30&t=188
viewtopic.php?f=17&t=1786&start=30#p13447
viewtopic.php?f=30&t=1429

Read the posts above but the basics are as follow:
Tower ground rods must be bonded to electrical service ground rods HEAVY #2 wire.

I always add 1 or 2 “new” ground rods to older existing electrical services.

Re: Wattage sensors blown?

Posted: Tue Oct 02, 2018 10:24 am
by gaspensonace
Thanks Chris. We've been having a lot of these issues and will look into best practices. I have implemented these practices at recent sites but there are a lot of older sites out there that haven't been done right. Appreciate the reply.