[Elecraft] 240V Line

[Fred Townsend]

It has been awhile since I have worked with the NEC but things haven't
changed that much for single phase. It has never been allowed for the
green/yellow lead to carry load current. Green and neutral must be the same
size as the current carrier even on a 240 circuit. Green and neutral may not
be circuit breakered. A 240 circuit may only be split (down to 120) at a
panel or sub panel and then each circuit must have its own circuit breaker.
120 volt circuits must have special plugs and sockets if breakered for at
more than 20 Amp. Panels or sub panels may not be placed in closets or
closely enclosed areas. (This is to avoid heat buildup.) Some areas are
requiring arc detecting or GFI interrupters on upgrades. If you install them
(generally a good idea) then place GFI/ARC type circuit breakers at the
panel. Do not place at load where RFI is likely to false trip. 
As warned local requirements may vary but this is sort of baseline stuff.
Nobody will fault you if you follow.
73
Fred, AE6QL

-----Original Message-----
From: Elecraft [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Jim
Brown
Sent: Wednesday, December 24, 2014 1:50 PM
To: Reflector Elecraft
Subject: Re: [Elecraft] 240V Line

On Wed,12/24/2014 11:41 AM, Charlie T, K3ICH wrote:
> A lot of the older amps (Thunderbolt for example) had 120 V fans wired 
> from one hot to ground. I always wondered about that.

I think that used to be legal, but it is no longer, and it's very bad
practice.

The better ones (Ten Tec Titan, for example) run a 120V fan between one side
of the power transfomer primary and the center tap. It is now illegal for
the Green wire to carry load current.

On Wed,12/24/2014 11:13 AM, Phil Kane wrote:
> IIRC the latest code update now requires the separate neutral ("white
> wire") to be run in all 240V circuits.  I did that in a 1969 when I 
> finished the basement in a year-old home!

You may be confusing a 120/240 outlet that has a four circuit plug (phase,
phase, neutral, and Green) and can serve both 120V and 240V loads, with a
240V outlet that has a three circuit plug and serves only 240V loads. There
is no neutral in a 240V outlet, and as noted above, it is illegal to connect
a 120V load between one phase and the Green wire (Equipment Ground).  That
120/240 circuit can feed both 120V and 240V outlets. A neutral IS required
to feed those 120V outlets.

73, Jim K9YC


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