So then you are trying to convince us that anyone who has a 240V dryer,
range, AC, Air Compressor or similar device with the neutral tied to the
ground at the wall outlet and at the device has a safety issue.
Sorry Tom, but the NEC manual disagrees with you and Id much rather follow
what the experts say.
And I have yet to see any 240V single phase ham amplifier manufacturer
provide a 4 wire cable.
In looking thru my amp manuals going back 40+ years I see that all 240V
configurations show the neutral connected to chassis ground. This, strangely
enough, includes Ameritron and verified with the AL-1200 on the bench for
As you state Tom, this really isn't complicated.
----- Original Message -----
From: "Tom W8JI" <email@example.com>
To: "Amps Amps" <firstname.lastname@example.org>
Sent: Sunday, July 08, 2007 3:36 PM
Subject: Re: [Amps] Transformer question
>> When I completely wired my current home I followed the NEC
>> code and had no problem with any level of inspection
>> including many 240V outlets in the shop, shack, and
> This really isn't complicated.
> If you have the neutral connected to the safety ground or to
> the chassis of any device at any point other than the main
> panel, you have faulty wiring.
> If there is any connection from the chassis or other exposed
> conductive parts to the power line neutral, you have faulty
> Any return currents for 120 have to be through the neutral,
> and the ONLY point the neutral can be connected to the
> safety ground is at the main breaker box.
> So if we build an amplifier and tie one end of a 120V
> transformer to the chassis, it is a safety issue. It doesn't
> pass code and also presents a hazard to the user.
> This means if you have a PA that uses a neutral return to
> obtain 120V it has to use a four wire outlet. You just
> shouldn't wire it to a three wire plug. We should never
> ground one primary end of a blower or filament transformer
> to the chassis. The reason being if the neutral opens the
> cabinet would have 120V on it.
> It has been this way by regulation at least 30 years now,
> and it was good common sense long before then. So unless he
> has a double insulated cabinet or a four wire outlet, he
> cannot simply ground the filament or control primary to the
> chassis or the safety ground of the power system.
> 73 Tom
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