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Topic Title: Clamping 50mm earth to a mast
Topic Summary: Which clamp?
Created On: 30 July 2012 09:15 PM
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 30 July 2012 09:15 PM
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djrichiet

Posts: 85
Joined: 23 April 2010

Hiya chaps,

I have an antenna mast going up which will need earth (lighting) protection. I will be running a piece of 50mm cable from near the top of the mast to an earth rod. Question is, what would be the best way of clamping the cable to the 50mm diameter (aluminium) mast?

Rather than crimping a lug on and drilling into the mast, I was wondering if there was some sort of band clamp available. Something a bit more trustworthy than a jubilee clip.

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From SMD's to 132kV... ive had a go!

Richard Talmage, LCGI EngTech TMIET
 30 July 2012 09:44 PM
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peteTLM

Posts: 3233
Joined: 31 March 2005

you can get 951 clamps big enough to go round a 4'' inch pipe if you look around or get them to order. Presumably though you will have lots of clamps going onto the pole anyway, why not use one of them?
As the pole is conductive, why not do it at the bottom of the mast??

Not sure the merits of an ad hoc LPS on a house(?) could cause more trouble than avoid it. If you get a strike, have you got surge protection on the rest of the installation or the neighbours? The LPS is supposed to be connected to the MET as well.
Id suggest looking at the Furse guide as my first point of call, one of the best free books going.

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Lack of planning on your part doesn't make it an emergency on mine....

Every man has to know his limitations- Dirty Harry
 30 July 2012 10:05 PM
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Avatar for Jobbo.
Jobbo

Posts: 915
Joined: 08 July 2010

We would normally use a wrap round clamp with ally tape, which you can purchase from most LPS installers.

Regards

Jobbo
 31 July 2012 07:48 AM
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Avatar for slittle.
slittle

Posts: 3596
Joined: 22 November 2007

Use Ally tape rather than 50mm copper, dis-similar metals etc.

Then as Jobbo says there are clamps available, the other option drill the tape and attach it to one of the U bolts.

Are you putting an earthing kit on the feeder too ?


Stu
 31 July 2012 10:55 PM
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Avatar for kj scott.
kj scott

Posts: 2144
Joined: 02 April 2006

Try here

Furse

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http://www.niceic.biz
 01 August 2012 05:50 PM
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djrichiet

Posts: 85
Joined: 23 April 2010

Cheers everyone, yeah the mast is in sections (with guy wire support) so would rather the earth be nearer the top of it to ensure better conductivity to earth. My attitude is if its going to get hit, then it will get hit anyway so rather a better path to earth with a rod than not, that way its not a dedicated 'lightning conductor'

The feeder itself is protected by an in-line surge protector, however with the earthed mast being more conductive to ground it would be better to attract most of the strike towards that.

Just were on top of a hill... and yep its for a CB radio. quite a few people coming back on the air now so thought why not

-------------------------
From SMD's to 132kV... ive had a go!

Richard Talmage, LCGI EngTech TMIET
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