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Must my 308 be earthed?

Started by jiimhoff, February 14, 2019, 07:57:40 PM

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Panasonic KX-T 30810 v3 PBX as a ground lug for earth ground.  There is no rod available nearby.  Shall I put it to an electrical ground nearby?  Or forget about it?  Or run a  35' wire out to the rod?  TYIA!  Happy Valentine's and hug a red phone.


You could run a #12 green ground wire to a local electrical ground that should be a sufficient ground.

Doug Rose

I have had a 616 working for over a dozen years, always plugged in with no ground. But that's just me. I never thought about until I saw your question.....Doug


I also have run many a system with no separate ground. That's basically there in high lightening areas. Or where a station would be run farther from the system, or to an out building.
The wall plug offers a ground provided though the electrical system of the building.
When I was installing systems, I would use the separate ground only if there was one handy, other wise.
That first response was made at 4:00 in the morning, after my eight year old who has a cold woke me up.. while waiting to fall asleep again I posted.


I too have had my Panasonic running 24/7 for years without a ground. I never gave it a thought.  Is the outlet grounding sufficent? Does the power cord have a ground wire in it? I do not recall what the plug looks like. Since a lot of us use this system what is the concensus? External ground or not?
Harry Smith
ATCA 4434

"There is no try,
there is only
do or do not"


I would think there are two reasons for grounding:

1) Protection from 110V electrical shock from the AC input - the 3 prong grounded AC cord should provide that protection.  The case is plastic and the user is generally insulated from the AC anyway, but that ground wire is connected to a part of the metal frame inside somewhere I'm sure.

2) Protection from lightning coming from the phone line on the pole.  This would only matter if your PBX is connected to an outside line that could attract charges in an electrical storm.   The earth ground lug inside would be for that purpose I believe.

Can any engineer confirm this thinking?


We have had traditions with 2 prong pugs, here in Norway, and you in the US. We actually have 2 prong outlets in the livingroom and bedrooms her in my house. That has never caused any problems for us.  The Panasonic is placed on the attic where the outlets are grounded, and that is all the grounding I have used for the it, it has been plugged in for about one decade. No problems! I have not even measured if it is any connection between the ground lug, and the ground wire on the Panasonic, but if it is I see a risk of having double ground.  Let us imagine a huge ground fault on the kitchen range causing a huge ground current, in worst case the voltage drop in grounding system may cause the current (or a considerable part of it) going trough the Panasonic to the good ground rod dedicated to that.  Where will the fire start? This scenario may need an error in the main grounding system, but who knows?

My way of thinking ends up with, if you have the dedicated grounding, disconnect the power grounding,  regular AFCI or GFCI systems does not disconnect the ground wire.

This way of thinking may violate NEC, in that case my opinion will be: NEC are wrong :-)



Any phone system would have a three wire cord with a three pronged connector for the electrical outlet. The third wire is ground, and as I explained previously, the ground leg is for lightning protection primarily and to provide a second ground in case the electrical ground is faulty.
It certainly doesn't hurt to have a system grounded, because if lightening hit even near an out side incoming line, the potential for a very large surge of current is going to find the path of least resistance. If you are touching the system in that moment, your that path of least resistance.
Ever been talking on the phone during a severe storm? You hear those clicks on the line? Those are strikes that have hit near or actually hit a areal line. I had instances where the bell actually rang just a ding, But I was glad I was not on the phone, because the acoustic shock that would have happened would have hurt my ear.
So yea it doesn't hurt to ground. And if you have a plug with the ground plug cut off, replace it with a proper grounded plug.