Yes Tony,
I added that bit in case someone wanted to get 120 volts from the 2 wire
plus ground receptacle.
While it will work if you use the ground wire as the neutral conductor,
it is a severe violation of code to do so, and it is highly dangerous
from a safety standpoint.
The KPA1500 is a pluggable device, not a hard-wired device (unlike a
range or a full house air conditioner).
In fact for wiring our air conditioner compressor, I ran 3 wires plus
ground (because that is what I had on hand), and the inspector required
that the 3rd conductor NOT be connected to anything, so it works both ways.
The way I see it:
If the device is permanently wired in, 2 wires and ground is desired and
sufficient.
If the device plugs into a receptacle with the possibility of adding a
120 volt receptacle from that wiring box, run 3 wires plus ground.
The neutral wire will be left unused unless a 4 wire receptacle or a 3
wire receptacle AND one or more 120 volt receptacles are added to the
box in the wall.
73,
Don W3FPR.
On 7/10/2018 10:10 AM, N2TK, Tony wrote:
Don,
I did not in any way suggest using the ground wire for current. But many
appliances such as the KPA1500, air compressors, water heater, etc. are 220VAC
devices that only require 2 wires plus ground. If you look at the plugs on
many of these type devices there are only three prongs - each phase plus
ground. There is no need for a neutral wire.
Yes, appliances like ovens and dryers where there is a need for 110 VAC besides
220VAC do need the neutral wire, hence the 4-wire plug.
I was commenting on the mention below of using 3 wires plus ground for the amp.
I can't see how that is necessary for a dedicated outlet for the amp. 2 wires
plus ground is quite sufficient.
73,
N2TK, Tony
-----Original Message-----
From: Don Wilhelm [mailto:[email protected]]
Sent: Tuesday, July 10, 2018 9:54 AM
To: N2TK, Tony <[email protected]>; [email protected];
[email protected]
Subject: Re: [Elecraft] Breakers for KPA1500?
Tony,
While it is possible and safe to use only two wires plug safety ground (Green
Wire Ground) for a 240 volt receptacle or 240 volt only device (in-home air
conditioner, dryer, etc), it is quite unsafe to split off for a 120 volt supply
using one hot and ground - in that case (such as a range that has a 120 volt
outlet on it or a 120 volt fan) you MUST run 3 conductors plus ground.
The ground wire should never carry current.
An inspector would never approve it, and if you value your insurance coverage,
don't try it - it will be found after the fire!
73,
Don W3FPR
On 7/10/2018 7:06 AM, N2TK, Tony wrote:
I do not understand the need for three wires plus ground. For a clothes dryer
outlet a neutral is required to get 110VAC from one of the phases to the
neutral. But for amps you only need both phases and a ground. The plugs are
three wire, not four.
73,
N2TK, Tony
-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of Jim Brown
Sent: Monday, July 09, 2018 8:40 PM
To: [email protected]
Subject: Re: [Elecraft] Breakers for KPA1500?
On 7/9/2018 12:26 PM, Bob McGraw K4TAX wrote:
I would also suggest using three - #10 with ground as the line from
the breakers to the amp operating position.
Not only a suggestion -- it's the law! Electrical Codes carry the force of law,
and they require that the equipment ground must 1) run with the current
carrying conductors and 2) must be no smaller than the largest conductor.
73, Jim K9YC
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