[TowerTalk] re GROUNDING OF FIELD DAY STATIONS

[Alan NV8A (ex. AB2OS)]

Just today I was reading a suggestion (on the "Grounding versus Bonding" 
forum at http://www.mikeholt.com/cgi-bin/codeforum/ultimatebb.cgi -- but 
they don't want to talk to "mere mortals," only to "professional" 
electricians, inspectors, etc.) that these Honda generators violate the 
NEC and should be condemned.

Alan NV8A


On 01/20/05 07:45 pm Peter Forbes tossed the following ingredients into 
the ever-growing pot of cybersoup:

> Interesting discussion points made by respondents regarding grounding, 3 wire extension leads and use of GFIs.
> 
> BE AWARE that not all setups can achieve this.
> 
> IN PARTICULAR, the HONDA series of generators, EU10i, EU20i, EU26i, which are used extensively worldwide do not have the neutral tied to earth.
> 
> If you measure between Active and Neutral you will achieve the rated voltage  (110 or 240), but Active to Earth or Neutral to Earth will give half the rated voltage in both cases.
> 
> There is an earth point on the generator (which should have an earth stake attached for safety and RFI purposes), but this means that MOST GFI's will NOT WORK in this situation, regardless of where they are placed in the layout.
> 
> This leads to a common (and dangerous) trick that operators will often do and that is to break the earth wire connection to eliminate any residual common mode RFI travelling from the generator along the earth wire.
> 
> The BETTER method is to make up a short extension lead (approximately 80 cm) with as many turns wound through ferrite toroids to eliminate RFI and plug this into the generator with the station extension leads plugging into this short extension lead.
> 
> WE have found 3 toroids in series to present sufficient impedance to be useful from 1.8 mhz upwards.
> 
> Most of the commercial filters available, do not filter the earth lead and in fact, often suggest the use of a dummy adaptor with the earth connection removed.  This is a dangerous practice in the field day situation.