Towertalk
[Top] [All Lists]

Re: [TowerTalk] UL listed protector for ladder line

To: towertalk@contesting.com
Subject: Re: [TowerTalk] UL listed protector for ladder line
From: "Jim Lux" <jim@luxfamily.com>
Date: Fri, 13 Jun 2025 13:02:33 -0400
List-post: <mailto:towertalk@contesting.com>
        


 
Yes, of course. And that would probably mean your relay box wouldn't need to be 
listed or stamped or whatever. Depending on what the AHJ is worried about.

Realistically exceedingly few hams build and install NEC compliant antenna 
systems. Or, at least, that they get them formally inspected from a NEC 
standpoint - typically the building inspector is concerned more about civil 
engineering/structural/geotechnical issues.  Which is why it's important to 
understand why Martin is looking for a listed Antenna Discharge Unit. 

Even at businesses (e.g. at work at JPL) I don't recall the building safety 
folks spending a lot of time on it, at least as far as NEC 810, 820 issues.  RF 
exposure - yes; structural (more "if it falls down, will it hit anything 
important"). And, of course, out of self interest, we want proper grounding and 
such, but nobody has come through looking for whether our hardware is listed or 
not.



On Fri, 13 Jun 2025 16:28:29 +0000, Paul Christensen <pbc.law@outlook.com> 
wrote:

>"This is all good stuff, BUT, if he's looking for regulatory compliance, he'd 
>have to get his relay box signed off by someone (either a test lab, or in some 
>jurisdictions, a Professional Engineer)."

I indicated that a suppressor could still be used with vacuum relays -- to your 
point, if required to satisfy a code provision. Nothing should prevent the use 
of vacuum relays together with a UL suppressor if the vacuum relays are 
positioned on the ladder line, away from the regulated premises.

Paul, W9AC

_______________________________________________



_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
 



_______________________________________________



_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
<Prev in Thread] Current Thread [Next in Thread>