Page 1 of 1

WS-8-150-AC current sensors

Posted: Sun Aug 19, 2018 10:54 pm
by lacibaci
So a year after I had my switch repaired, here we go again, it seems two of my ports have blown current sensors (ports work but report huge ~40W power usage)
I checked everything, an electrician inspected for proper grounding and all seems OK.
My installation is very simple: Residential house, single power distribution box. Five POE cameras and one UBNT WiFi AC plugged into the switch with shielded CAT6 cable via UBNT ethernet surge protectors. The switch itself is plugged into a UPS that is usually able keep it up for ~40 minutes.
A few days ago we had a power outage (about an hour) The UPS shut down and when everything came up, two ports started reporting very large power usage. All devices are working correctly and the switch is stlll passing traffic.

I still like this switch and would like to continue using it, however; I don't know if I trust it anymore to supply power. I am thinking I'll have the switch repaired, turn off the POE and use power injectors to supply POE or buy a dumb POE switch (like from WiFi Texas) and loose all management features.

Now my question: is it still $50 service for repairing two ports?

Re: WS-8-150-AC current sensors

Posted: Mon Aug 20, 2018 9:55 am
by sirhc
lacibaci- WS-8-150-AC current sensors wrote:So a year after I had my switch repaired, here we go again, it seems two of my ports have blown current sensors (ports work but report huge ~40W power usage)


Thats weird as the WS-8-150-AC does not have current sensors on the ports.


You obviously have a ground issue. I would add 2 NEW ground rods to the electrical service. Visual inspection of ground rods will tell you nothing. Ground rods act differently when you introduce rain/water. Ground rods MUST penetrate clay subsoil 18" to not be affected by water/rain.

Do not use Ethernet Surge protectors with passive POE switches like Netonix and ToughSwitch because an Ethernet Surge protector works by clamping all 8 wires together and to ESD ground wire if present which is a dead short. 99% of WISP damage is from ground current not ESD. If you lose the Ethernet port in a radio or device but the radio or other parts still work this is ground current not ESD or Static.

This has been discussed on this forum UBNT Forum, and many social media WISP groups.
If you receive a surge from the AC power side the AC surge protector has you protected and besides to damage the switch's board and or equipment powered by it the power supply would be dead from said surge.

UBNT Ethernet Surge protectors work fine with the POE brick they provide as they will not be damaged from shorts as they have short circuit protection. Netonix and ToughSwitch do not have this because you would need a circuit for each port and would add a lot of expense and size to the switch.

The power outage was probably due to a storm which had RAIN. Rain is what cause ground current shift if the electrical service ground rods are not sufficient as the water wicks and runs down the rods momentarily reduce its capacity.

Add NEW service ground rods.

Re: WS-8-150-AC current sensors

Posted: Mon Aug 20, 2018 2:35 pm
by jakematic
We've discussed this before here: viewtopic.php?f=17&t=2874&p=19750#p19784

I suspect a ground loop/differential on your "uplink" port. Or something else in the mix that we can't see via the internet.

Since my last reply I've spent a considerable pile of cash to replace the breaker box and had additional ground rods driven.
Mine was a Federal Pacific (aka Fire Pacific aka Fisher Price Electric) that was UNSAFE and failed to trip during an actual event when a contractor drove a screw through Romex.

My power is much more stable now, and the grounding and isolation I use keeps everything happy.
Of note some of my circuits had the live/neutral incorrectly wired. At the BREAKERS !
And it was all checked out and passed by a certified electrical inspector before buying this house from the engineer who holds the patent on the FPE Stab-Lok.

I trust these switches hands down.
Replacing them with dumb switches and PoE injectors will just mask the problem - I shitcanned a pile of Netgear that was faulty due to issues caused by bad ground.

My 2 cent.

Re: WS-8-150-AC current sensors

Posted: Mon Aug 20, 2018 8:37 pm
by lacibaci
Ok, I'll have a different electrician come and check it out again.
In the mean time how do I go about fixing the switch hopefully for the last time?

Re: WS-8-150-AC current sensors

Posted: Tue Aug 21, 2018 9:20 am
by sirhc
lacibaci wrote:Ok, I'll have a different electrician come and check it out again.
In the mean time how do I go about fixing the switch hopefully for the last time?


AS I said I was confused as you state a WS-8-150-AC and port current sensors which that model does not have?

But if the switch is damaged I would RMA it for repair.

You can hire an electrician but most residential electrician are not going to understand ground current very well as that is why the telecommunication industry has a much more stringent standard for grounding.

As I said I would add a couple NEW Earth Ground rods to the electrical service seperated by 4-6 feet binded to the old rods and clean up any corrosion.

If there is a tower involved make sure service ground rods are bonded to tower ground rods.

If you are running an Ethernet cable to a device that is powered from another service panel or worse yet another service this is BAD, you should run fiber from one device to another if on different services or even panels as the ground potential will be different between them and the Ethernet cable provides this bonded path and POOF.

I send the follow back to all customer repaired RMAs in hopes they will read and heed my warnings, most do not sadly:

99% of all WISP equipment damage is from ground current (I own a WISP)
Another common cause for damage is a shorted cable or incorrect POE option applied to device.

Here are some good posts on grounding:
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:
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