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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> >>
> >>
> >
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