Elecraft

240V Line

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Jim Brown-10

240V Line

Installing a 240V outlet is not a big deal unless the construction of
your home makes it difficult to run the cable. Barring that, a competent
electrician should be able to do that in a half day; a difficult run
could double the work. All that is required is a pair plus a Green wire.
If you also want 120V outlets from the same circuit, you'll need another
conductor for the neutral.

A single 20A 120/240V circuit will run all the ham gear in most
stations, even for SO2R. If you're smart, you'll use #10 copper, 20A
outlets, and a 20A breaker. While #10 is rated for 30A, our stations
don't need 30A, but the bigger copper will reduce the voltage drop.

There are MAJOR advantages to running all the gear in our stations from
outlets that share the same Green wire, or outlets whose Green wires are
bonded together. See http://k9yc.com/GroundingAndAudio.pdf

73, Jim K9YC
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Phil Kane-2

Re: 240V Line

On 12/24/2014 10:39 AM, Jim Brown wrote:

> Installing a 240V outlet is not a big deal unless the construction of
> your home makes it difficult to run the cable. Barring that, a competent
> electrician should be able to do that in a half day; a difficult run
> could double the work. All that is required is a pair plus a Green wire.
> If you also want 120V outlets from the same circuit, you'll need another
> conductor for the neutral.

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!

73 de K2ASP - Phil Kane
Elecraft K2/100 s/n 5402

From a Clearing in the Silicon Forest
Beaverton (Washington County) Oregon
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George Dubovsky

Re: 240V Line

On Wed, Dec 24, 2014 at 2:13 PM, Phil Kane <[hidden email]> wrote:

>
> On 12/24/2014 10:39 AM, Jim Brown wrote:
>
> > Installing a 240V outlet is not a big deal unless the construction of
> > your home makes it difficult to run the cable. Barring that, a competent
> > electrician should be able to do that in a half day; a difficult run
> > could double the work. All that is required is a pair plus a Green wire.
> > If you also want 120V outlets from the same circuit, you'll need another
> > conductor for the neutral.
>
> 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!
>

Even if that is true,and I suspect "all" is a mis-statement, that doesn't
automatically mean that YOUR Authority Having Jurisdiction has adopted the
latest code (or the previous one or the one before that). Things move
slowly in some places.

73,

geo - n4ua

>
> 73 de K2ASP - Phil Kane
> Elecraft K2/100 s/n 5402
>
> From a Clearing in the Silicon Forest
> Beaverton (Washington County) Oregon
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Jim Brown-10

Re: 240V Line

In reply to this post by Jim Brown-10

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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Alan Bloom

Re: 240V Line

Electric ranges used to have a 110 VAC outlet in which the ground and
neutral were wired together. (The 220V plug had only three prongs.) I
always wondered how they got away with that.

Alan N1AL

On 12/24/2014 01:50 PM, Jim Brown wrote:

> 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
>
>
> ______________________________________________________________
> Elecraft mailing list
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>
>

Fred Townsend-2

Re: 240V Line

In reply to this post by Jim Brown-10

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:[hidden email]] 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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Edward R Cole

Re: 240V Line

In reply to this post by Jim Brown-10

In retrospect, its better if you contract a licensed electrician to
run 240v wiring as his license is at risk and is liable if codes are
violated. If you are not sure of the code and regulations, then I
would say don't DIY.

I am lucky as there is no zoning or covenants where I live. Legally,
perhaps a building permit is required (by the county) but standard
practise is to ignore it if owner built. I put up a 12x38-foot shed
wired with lights and added a backyard driveway with no permits. The
property assessor has visited since and added the improvements with
nothing said.

But this is rural Alaska where things are more relaxed. Also, I
worked for a licensed electrician when I was younger so I am familiar
with std practise. I hired electrical work at my old workplace so I
had a business relationship with electrical contractor who was
willing to sign-off on my work (he did the inspection).

My prior home was owner-built in 1955 & 1971 and wired by the owner
with 2-wire outlets. FHA bought off on that (grandfathered it) so I
did not have to rewire the house (newer half was done with U-ground
outlets. I did have to fix a bunch of ground faults and other
mistakes and add GFI outlets in kitchen and bathroom. I opened one
outlet in the utility room to find black charred wiring (I removed
the outlet and used a blank cover and removed the circuit at the breaker box).

But current home is built in 1994 and modern five-star energy home -
done right. A plus is that utilities are buried so HF line noise is
low. Ham radio was a consideration when we chose the home.

73, Ed - KL7UW
http://www.kl7uw.com
"Kits made by KL7UW"
Dubus Mag business:
[hidden email]

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Tim Groat

Re: 240V Line

In reply to this post by Jim Brown-10

What Jim says here is correct.

The old exception that allowed returning 120V loads to the bare or green
grounding wire of a 240V circuit was very limited, allowed only for a
few large appliances (dryers, stoves/ovens, and water heaters IIRC)
which would be disconnected only for maintenance or replacement. The
exception never applied to ham equipment.

There are at least three possible Bad Things that can happen when you
use a ground to carry operating current:

(1) Some of the 120V load current returns by way of the coax, keying
line, ALC line, the rig and its power supply, the antenna grounding
system, etc.--anything connected to the amplifier chassis. This current
often causes a stubborn hum in your transmitted signal (and other ill
effects).

(2) If the circuit has GFCI protection, the 120V load current is likely
to trip the GFCI.

(3) If the ground wire opens for any reason, the 120V load current has
nowhere to go except the unintended paths, in particular through you if
you are touching anything connected to the amplifier. This danger is the
primary reason the NEC no longer allows combining neutral and ground
conductors anywhere beyond the power service equipment (master
disconnect enclosure).

So if you have an older amplifier wired with 120V loads to chassis, it's
wise to spend the time and money to make it safer and better by keeping
the 120V load currents out of the chassis ground connections.

--Tim (KR0u)

On 12/24/2014 2:50 PM, Jim Brown wrote:
>
> 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.

---
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Edward R Cole

Re: 240V Line

In reply to this post by Jim Brown-10

I concur. As result of this discussion and because I will soon add
another 240vac outlet to serve my 50v-50a switching PS being
installed to power a 1100w surplus ch.2 TV Harris amplifier (for use
on 6m), I looked closely at some of the twist-lock plugs I had in my parts.

They are three contact plugs, so are unable to carry a safety ground
for splitting out 120vac. They are legal for 240vac as the third
contact is the safety ground. When wiring my shack for 240vac I
bought No.8-4 conductor cable (three-No. 8 and one solid copper No.12
wire in the cable. So the 60amp load box is properly connected to
provide 120v break out as well as 240vac with standard breakers. But
my 240v outlets are only good for 240v as a result. My 4-kV HVPS
uses both 240 and 120v and has two separate power cables supplying
this (properly oriented neutrals and safety grounds).

As Tim says, below, improper wiring can lead to bad operating
conditions and UNSAFE operations. If you do not understand any part
of what is being said - then you should not do the 240v wiring - hire
a reputable, licensed, bonded electrician.

Several years ago a local store owner had some wiring done in his
house by a "friend" that "knew" electrical wiring. The friend
connected the 240v service incorrectly cross connecting one of the
hot and the neutral which resulted in all the 120v circuits carrying
240v. The store owner lost his furnace blower, microwave, TV,
stereo, and most of his lights to the tune of several thousand
dollars - but saved on (not) hiring a competent
electrician. Fortunately no was harmed and his house did not burn down!

73, Ed - KL7UW
----------------------
Date: Mon, 29 Dec 2014 19:12:46 -0700
From: Tim Groat <[hidden email]>
To: elecraft <[hidden email]>
Subject: Re: [Elecraft] 240V Line
Message-ID: <[hidden email]>
Content-Type: text/plain; charset=utf-8; format=flowed

What Jim says here is correct.

The old exception that allowed returning 120V loads to the bare or green
grounding wire of a 240V circuit was very limited, allowed only for a
few large appliances (dryers, stoves/ovens, and water heaters IIRC)
which would be disconnected only for maintenance or replacement. The
exception never applied to ham equipment.

There are at least three possible Bad Things that can happen when you
use a ground to carry operating current:

(1) Some of the 120V load current returns by way of the coax, keying
line, ALC line, the rig and its power supply, the antenna grounding
system, etc.--anything connected to the amplifier chassis. This current
often causes a stubborn hum in your transmitted signal (and other ill
effects).

(2) If the circuit has GFCI protection, the 120V load current is likely
to trip the GFCI.

(3) If the ground wire opens for any reason, the 120V load current has
nowhere to go except the unintended paths, in particular through you if
you are touching anything connected to the amplifier. This danger is the
primary reason the NEC no longer allows combining neutral and ground
conductors anywhere beyond the power service equipment (master
disconnect enclosure).

So if you have an older amplifier wired with 120V loads to chassis, it's
wise to spend the time and money to make it safer and better by keeping
the 120V load currents out of the chassis ground connections.

--Tim (KR0u)

73, Ed - KL7UW
http://www.kl7uw.com
"Kits made by KL7UW"
Dubus Mag business:
[hidden email]

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Jim Brown-10

Re: 240V Line

On Tue,12/30/2014 12:01 AM, Edward R Cole wrote:
> I concur. As result of this discussion and because I will soon add
> another 240vac outlet to serve my 50v-50a switching PS being installed
> to power a 1100w surplus ch.2 TV Harris amplifier (for use on 6m), I
> looked closely at some of the twist-lock plugs I had in my parts.
>
> They are three contact plugs, so are unable to carry a safety ground
> for splitting out 120vac.

WRONG! ALL power outlets MUST include safety ground (the green wire).
To do otherwise is both unsafe and a violation of virtually all building
codes in the civilized world. A 240V outlet with a 3-circuit plug MUST
carry the two 240V phase conductors and GROUND, NOT NEUTRAL. If you want
to connect equipment that includes a 120V load to that circuit, you MUST
use a 4-circuit plug for that load.

In North America, nearly all homes are supplied by a transformer
(outside the premises) with a center-tapped 240V secondary. The center
tap is the neutral. 240V loads are connected end-to end, 120V loads are
connected end to neutral. Those ends are called "phases." To connect
dedicated 120V loads to that circuit, the 120V outlets must have one of
the "phase" conductors, neutral, and ground. To equalize loading, it's
good practice to split those 120V outlets between the two phase
conductors (that is, opposing sides of the 240V transformer).

> They are legal for 240vac as the third contact is the safety ground.

Yes.

> When wiring my shack for 240vac I bought No.8-4 conductor cable
> (three-No. 8 and one solid copper No.12 wire in the cable. So the
> 60amp load box is properly connected to provide 120v break out as well
> as 240vac with standard breakers. But my 240v outlets are only good
> for 240v as a result.

That sounds fine, except that what you can connect to those 240V
outlets depends on how they are wired. If they are 3-circuit outlets
with phase, phase, and ground, you can, indeed, connect only a 240V
load. If they are 4-circuit outlets with phase, phase, neutral, and
ground, you can connect a load that draws both 240V between the phases
and 120V from one phase to neutral. Also, I'd be concerned about the
size of that ground conductor. In general, the ground conductor must be
sized at least equal to the phase conductors.

73, Jim K9YC
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Phil Kane-2

Re: 240V Line

On 12/30/2014 9:35 AM, Jim Brown wrote:

> In general, the ground conductor must be sized at least equal to the
> phase conductors.

I was always under the impression that the ground wire must be sized for
the circuit overcurrent rating (i.e. breaker/fuse rating). I have on
several occasions specified circuit (and neutral) ampacities greater
than the overcurrent rating just to eliminate voltage drop at the load.
This is important in low-voltage (12/24/48 v) applications in comm centers.

73 de K2ASP - Phil Kane
Elecraft K2/100 s/n 5402

From a Clearing in the Silicon Forest
Beaverton (Washington County) Oregon
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Alan Bloom

Re: 240V Line

In reply to this post by Jim Brown-10

I'm not an electrician, but I am currently having my house wiring
re-done by an electrician and this is my understanding:

If you want to run 220V and 110V outlets from the same breaker, you need
to use a sub-panel with separate breakers for the 110V circuits. Four
wires are needed from the main panel, two hots, neutral and ground. The
ground can be a smaller gauge so long as it goes only to circuits that
are protected by a circuit breaker suited for that gauge.

I did something similar to that when I wired my well, which is about 400
ft away from my house. I wanted a 110V outlet and light in the pump
house as well as 220V for the pump.

Alan N1AL

On 12/30/2014 09:35 AM, Jim Brown wrote:

> On Tue,12/30/2014 12:01 AM, Edward R Cole wrote:
>
>> When wiring my shack for 240vac I bought No.8-4 conductor cable
>> (three-No. 8 and one solid copper No.12 wire in the cable. So the
>> 60amp load box is properly connected to provide 120v break out as
>> well as 240vac with standard breakers. But my 240v outlets are only
>> good for 240v as a result.
>
> That sounds fine, except that what you can connect to those 240V
> outlets depends on how they are wired. If they are 3-circuit outlets
> with phase, phase, and ground, you can, indeed, connect only a 240V
> load. If they are 4-circuit outlets with phase, phase, neutral, and
> ground, you can connect a load that draws both 240V between the phases
> and 120V from one phase to neutral. Also, I'd be concerned about the
> size of that ground conductor. In general, the ground conductor must
> be sized at least equal to the phase conductors.

Eric Swartz - WA6HHQ

Re: 240V Line

Administrator

In reply to this post by Jim Brown-10

Folks - Let's close this thread for now to reduce list SNR due to the large
volume of posts.

In the future, please also refrain from using ALL CAPS and "!" in emails, as
those are interpreted as shouting and are not appropriate for this list.

73,

Eric
elecraft.com

On 12/30/2014 9:35 AM, Jim Brown wrote:

> On Tue,12/30/2014 12:01 AM, Edward R Cole wrote:
>> I concur. As result of this discussion and because I will soon add another
>> 240vac outlet to serve my 50v-50a switching PS being installed to power a
>> 1100w surplus ch.2 TV Harris amplifier (for use on 6m), I looked closely at
>> some of the twist-lock plugs I had in my parts.
>>
>> They are three contact plugs, so are unable to carry a safety ground for
>> splitting out 120vac.
>
> WRONG! ALL power outlets MUST include safety ground (the green wire). To do
> otherwise is both unsafe and a violation