Advice on protecting panasonic kx-ns5162 doorbell system from lightning surges? PART 2

[Jupiter99]

Since the Original Post on this topic has been locked, I am continuing here the discussion.
Just quoting my original question:

Hi everyone,

I'm seeking advice on protecting my home doorbell system from lightning surges. I’ve had success in safeguarding my network equipment (switches, routers, etc.) using Ethernet-to-fiber-optic adapters paired with a UPS system, but I’m still facing issues with my Panasonic KX-NS5162 module connected to an NS 500 PBX system. Every time there’s a strong storm, the doorbell system gets damaged, requiring a module replacement

Has anyone encountered this issue or found a solution? I’d appreciate any suggestions on surge protection devices, grounding methods, or any other ideas that could help protect this setup.

This is the connection scheme, maybe some wires could be protected somehow?

@martincom , in your opinion, could I use a fuse on each cable right after the ethernet port on the Panasonic Door Opener card?

I could split each cable entering the ethernet port with a fuse. Would this protect the card and the same time allow proper work, both on the voice/intercom end and door opener end? What Amperage would you start with?
Any help appreciated!
Thanks!

 

[daddybadger]

Why not replace the door phone for an IP intercom from fanvil or 2n and then you can use those ethernet surge protectors. Presumably you want to protect the dph2 card, back in the day we used those krone strip surge protectors. I've had the same instance of bad cards due to surge current.

 

[Jupiter99]

Because the Panasonic would be an all-in-one solid integrated system if only I could find a way to protect the system somehow. Why wouldn't you directly use the surge protectors in front of the Panasonic doorphone card?

 

[martincom]

I don't think a fuse will do much for you. I doubt if it would act fast enough (blow) before the damage was already done. Bear in mind the current has to exceed the fuse rating before it blows, so the card ports will be exposed to the surge.

As I indicated in my previous post, the telephone company (telco) outdoor network demarcation box/protector have been doing the job for me and I have a fairly long run of buried cable (+1000 feet). I'm also utilizing the relay contacts of the KX-NS5162 to operate the driveway gate and I haven't had any issues the electronics of the gate controller, either. I preferred the telco network interface/protector as it also provided a weathertite enclosure for the connections, as there was no structure at the gate.

If cost is not an object, we utilized surge protectors from company called Polyphaser, in my business, which was two-way radio communications. We had equipment installations on towers ranging from 50' to 1000', so they were frequently struck.

I measured the "talk" battery, from the KX-NS5162 and it was about 6 VDC. So you'd want to utilize a protector such as the IX-2H, which has a turn on voltage of 9 VDC. If you're utilizing the relay contacts of the card, you'll want to select a protector with a greater voltage than what is across the contacts when open.

Telco network interface/protectors typically have a turn on voltage greater than 125 VAC, as typical ring voltage is around 90-110VAC. Here are some links to some I found on Ebay. search I searched for "telephone network interface".

Corning Cable Systems SRP-207-200 6 Line ADSL Telephone Network Interface 5-1 | eBay

It has been fully tested to ensure there are no issues with the item. Number of Lines 6.

www.ebay.com

Keptel SNI-4300 Telephone Network Interface. | eBay

Find many great new & used options and get the best deals for Keptel SNI-4300 Telephone Network Interface. at the best online prices at eBay! Free shipping for many products!

www.ebay.com

Vtg Bell Atlantic Sys 91011801 Network Interface Device T11 Model 3712H-7-250/NX | eBay

Find many great new & used options and get the best deals for Vtg Bell Atlantic Sys 91011801 Network Interface Device T11 Model 3712H-7-250/NX at the best online prices at eBay! Free shipping for many products!

www.ebay.com

Corning Cac 900 telephone network interface | eBay

Corning Cac 900 telephone network interface. Condition is New. Shipped with USPS Priority Mail.

www.ebay.com

 

[martincom]

Of course, any surge protection is only going to be as good as the earth ground you connect it to.

 

[Jupiter99]

Hello Martin,
in my case the electrical wires path is unknown since it was there before I came in. There are multiple hardware switches in the building which allow opening manually the gates. As posted in the OP, this is why the door opener circuitery is not under my full control, and probably not properly grounded, making it difficult for me to properly defend these additional circuits. At the same time, I'd rather avoid pulling new cables through electrical conduits for this purpose.

Your thoughts?

 

[martincom]

Which portion of the KX-NS5162 is being damaged, the intercom, the gate controller, or both? Is any portion of the cabling buried? If so, direct burial or within conduit?

 

[martincom]

What is the open circuit voltage from the gate?

 

[Jupiter99]

Which portion of the KX-NS5162 is being damaged, the intercom, the gate controller, or both? Is any portion of the cabling buried? If so, direct burial or within conduit?

Both card portions are damaged. Yes, cables are buried for at least 50 meters in a corrugated flexible conduit

What is the open circuit voltage from the gate?

This requires further investigation. How could I test this with an electrical tester? I hope it is not and old 220V circuit. I could probably inquire the gate engine's tech support...

 

[martincom]

To measure the open circuit voltage, simply connect a voltmeter across the pair that serves the relay contacts, within the KX-NS5162. Pins 1 & 2, for door opener #1, or pins 7 & 8, for door opener #2 of the door opener jack. Start with the meter set to measure AC voltage first and follow by changing it to read DC voltage. It could be either or. You do not need to disconnect anything.

 

[daddybadger]

Because the Panasonic would be an all-in-one solid integrated system if only I could find a way to protect the system somehow. Why wouldn't you directly use the surge protectors in front of the Panasonic doorphone card?

They won't be compatible.

 

[Jupiter99]

What is the open circuit voltage from the gate?

Measured on the Ethernet plug

 

[Jupiter99]

BTW, I had a chat with an electrician who thinks that the buried cable is long enough to suffer from lightning strike induction..