[TenTec] TT 940 Power Supply

[denton sprague]

My big Cyberpower is still under warranty…they don't even want you running an extension cord out of the socket!
When I was testing it, I noticed rf hash in spots throughout 80 and 40 meters….and I ordered it new specifying for telecommunications use!
Will keep in mind what you typed below when I pull the case apart for twice annual dust bunny removal next winter. 
On Sep 2, 2014, at 12:31 PM, "Bob McGraw - K4TAX" <RMcGraw at Blomand.net> wrote:

> You raise a point regarding "industrial grade sine wave ups".   I have one of those and in my chasing a noise issue, I opened the case to find the output receptacles each have the neutral terminal {white wire} and the 3rd pin ground terminal {green wire}connected by a solid strap.  This then says the neutral is connected to 3rd pin ground at several points, both on the input and output.  I seem to recall this is not correct according to NEC.
> 
> Anyway, I removed the straps and my noise went away.  Now, this does leave the 3rd pin AC ground terminal on the LOAD side of the UPS connected to the 3rd pin ground on the INPUT side of the UPS.  The neutral however is not connected from the LOAD side to the INPUT side, thus there is significant isolation between input and output of the UPS.  As it should be in my thinking.
> 
> Is there some UL requirement, say UL1499, or other international standard that I'm not aware that mandates the load neutral and 3rd pin AC must be bonded?  It has been too many years since I worked in this part of the safety discipline.
> 
> Comments anyone?
> 
> 73
> Bob, K4TAX
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