This does not tell you if it is right or wrong in this situation.
Not sure how the code reads today, but a couple of years ago this type of
hookup was perfectly ok. The code said that if a sub panel was located in
the same building then a ground wire must be run between the main panel and
the sub panel and the sub panel must have the neutral and ground conductors
isolated.
However in a detached building you could run only 3 wires, two hot lines and
a neutral. In the sub panel the neutral was to be connected to the neutral
buss and to the ground buss just like in the main panel. In addition the sub
panel must have a local ground rod attached. Just as Mark describes.
73
Gary K4FMX
> -----Original Message-----
> From: amps-bounces@contesting.com [mailto:amps-bounces@contesting.com] On
> Behalf Of Ian Hill - K8MM
> Sent: Tuesday, November 03, 2009 10:49 AM
> Cc: amps@contesting.com
> Subject: Re: [Amps] TL922 Power Plugs
>
> You beat me to it....lol
>
> Ian - K8MM
>
> maflynn@att.net wrote:
> > Not allowed by code: NFPA 70: 408.20 Grounding of Panelboards.
> Panelboard cabinets and panelboard frames, if of metal, shall be in
> physical contact with each other and shall be grounded. Where the
> panelboard is used with nonmetallic raceway or cable or where separate
> grounding conductors are provided, a terminal bar for the grounding
> conductors shall be secured inside the cabinet. The terminal bar shall be
> bonded to the cabinet and panelboard frame, if of metal; otherwise it
> shall be connected to the grounding conductor that is run with the
> conductors feeding the panelboard.
> >
> >
> > Grounding conductors shall not be connected to a terminal bar provided
> for grounded conductors (may be a neutral) unless the bar is identified
> for the purpose and is located where interconnection between equipment
> grounding conductors and grounded circuit conductors is permitted or
> required by Article 250.
> >
> >
> > -------------- Original message from "Mark Robinson"
> <markrob@mindspring.com>: --------------
> >
> >
> >
> >> My Neutral and Ground is connected at the main panel but also at the
> barn
> >> 300 feet away. I am running a 3 wire 100 amp 240v power 4 00 aluminum
> line
> >> to the barn from a 100 amp 240v breaker located in my main distribution
> box.
> >> I didn't like the idea of a gnd neutral tie that far away from the
> barn, so
> >> I tied them together at the barn with a second ground rod located at
> the
> >> barn. Is that such a bad idea?
> >>
> >> Mark
> >>
> >>
> >> ----- Original Message -----
> >> From: "Ian Hill - K8MM"
> >> Cc:
> >> Sent: Tuesday, 03 November, 2009 10:24 AM
> >> Subject: Re: [Amps] TL922 Power Plugs
> >>
> >>
> >>
> >>> There isn't anything ILLEGAL about connecting the neutral and ground
> >>> anywhere else beside the main panel. You're violating the NEC but not
> >>> committing a criminal offense. ;-)
> >>>
> >>> K8MM
> >>>
> >>>
> >>> Jim Brown wrote:
> >>>
> >>>> On Thu, 29 Oct 2009 18:17:21 -0400, Ian Hill - K8MM wrote:
> >>>>
> >>>>
> >>>>
> >>>>> Houses are typically feed off of a center tapped secondary. 240V
> >>>>> measured between phase conductors and 120V between either phase
> >>>>> conductor and the center tap. There isn't any sort of dangerous
> short
> >>>>> by having the neutral ( i.e. center tap) and the ground bonded
> together
> >>>>> in the primary distribution panel in a house....its supposed to be
> >>>>> connected that way.
> >>>>>
> >>>>>
> >>>> Exactly right. One other VERY important point -- it is both ILLEGAL
> and
> >>>> UNSAFE to connect neutral to ground at any other point. The proper
> >>>> connection of a 240V load is to the two ends of the transformer only,
> >>>> and with the ground wire connected for safety.
> >>>>
> >>>> There is some equipment that needs both 240V and 120V to operate.
> That
> >>>> equipment gets its 240V from the two ends of the transformer, and
> MUST
> >>>> get 120V between one side of the transformer and NEUTRAL, NOT GROUND.
> >>>>
> >>>> 73,
> >>>>
> >>>> Jim Brown K9YC
> >>>>
> >>>>
> >>>>
> >>>> _______________________________________________
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> >>>> http://lists.contesting.com/mailman/listinfo/amps
> >>>>
> >>>>
> >>>>
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> >>>
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