[TowerTalk] utility box and feed-throughs

Dick Green WC1M wc1m73 at gmail.com
Fri Apr 19 23:33:16 EDT 2013

Following up on the big hole in the bottom of the box, they make PVC
feed-through bushings that will keep the cables from abrading against the
cut metal edges of the hole. Water won't get into the box, and if you press
the cables tightly together you can do a pretty good job sealing the opening
against insects. You can stuff steel wool and/or coax seal around the cable
bundle to keep small critters and insects out.

Now, did I understand correctly that you've pulled a 115V line through the
same conduit as your low voltage cables? Even if you only turn it on when
you need it, that's a code violation. If the AC line insulation was
compromised during the pull, or some critter gets in there and chews it, you
could wind up with lethal voltage on one of your low voltage lines, with
serious risk to life and property. I don't care how confident you are that
this can't happen. It's a code violation for a reason. You really need to
pull that AC line through a separate conduit.

73, Dick WC1M

> -----Original Message-----
> From: Hans Hammarquist [mailto:hanslg at aol.com]
> Sent: Friday, April 19, 2013 4:48 PM
> To: towertalk at contesting.com
> Subject: [TowerTalk] utility box and feed-throughs
> I am planning to put a box near the top of my tower and use it for
> various signal wire connections such as rotator cables, antenna switches
> etc. My idea was to pull a multi-conductor cable between my shack and
> this box, have several screw terminals in the box to attach whatever I
> need signal and power for. (Yes, I have a 115 V output in the tower
> already. It has survived several winters so far. No, I don't have power
> on it unless I need to.)
> In order to make the box reasonable water tight I plane to use regular,
> sealed feedtrough for the cable. My dilemma is: What feed-through do I
> use for the cables between the rotators and the switches etc and the
> box? I can add a sealed feed-through each time I need a new connection
> but that requires me to make a hole in the box and put a sealed feed-
> through each time. Not a big deal if yuo are on the ground or in your
> work shop but hanging by one arm, 80 feed up does not appeal to me.
> Is there anything out there made for this purpose? It needs to be very
> easy to use, be able to accept several cables, if so small and it needs
> to be able to seal out at least insects but water is also not very
> welcome.
> 73 de,
> Hans - N2JFS

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