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Re: Primary Coil...

[snip a section describing different primary coil materials]

>In my primaries I've use heavy-PVC sleeved Copper water pipe, but on future
>primarieswill change to a HDPE sleeving. 'Poly pipe'  micro-irrigation tube
>is a verycheap sleeving material. Plastic sleevings are not as beautifull as
>bare copper, but Ive never had a 'flashover' since.  
>
>Marcus 
> 

Telephone companies place huge (over 3 inch diameter) cables in underground 
conduits.  Much of this cable is pressurized with dry nitrogen.  The 
nitrogen is supplied to the cable through "air pipe".  Air pipe is a 
polyethyelene covered thin aluminum tube.  It has about the same flexibility 
as large garden water hose.  The diameter is about 1 inch, and since most of 
the current we deal with is skin effect, tubing works quite well.  I have 
used this air pipe to make a big primary and it worked very well - the poly 
covering helps reduce flashovers and corona loss.  Telephone companies (or 
their contractors) will often replace thousands of feet of this air pipe and 
just throw the old away.  Make friends with a telephone company splicer or 
placing contractor.

bert