Basically what it comes down to is whatever the authority having
jurisdiction decides is "right". Whether its what the NEC says, is
really irrelevant to some guys. The great majority of the time
inspectors want you to have the ground buss separate from the neutral
buss in a sub panel no matter what article 250 says. You don't have to
satisfy article 250, you have to satisfy the inspector. They take a much
harder stance against a homeowners interpretation of something in the
NEC verses a licensed master electrician. HO's tend to do foolish things
whenever they decide to modify their electrical power systems at a later
date and taking a hard stance on certain rules helps protect HO's from
themselves.
Ian - K8MM
Mark Robinson wrote:
> it says........... unless permitted or required by Article 250.
>
> My question is what does Article 250 say?
>
> ----- Original Message ----- From: "Ian Hill - K8MM" <ihk8mm@charter.net>
> To: "Mark Robinson" <markrob@mindspring.com>
> Sent: Tuesday, 03 November, 2009 11:11 AM
> Subject: Re: [Amps] TL922 Power Plugs
>
>
>> What is your question?
>>
>>
>> Mark Robinson wrote:
>>> 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.
>>>
>>>
>>>
>>> what does article 250 say
>>>
>>>
>>> ----- Original Message ----- From: "Ian Hill - K8MM"
>>> <ihk8mm@charter.net>
>>> Cc: <amps@contesting.com>
>>> Sent: Tuesday, 03 November, 2009 10:49 AM
>>> 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
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> _______________________________________________
>>>>>>>> Amps mailing list
>>>>>>>> Amps@contesting.com
>>>>>>>> http://lists.contesting.com/mailman/listinfo/amps
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>> _______________________________________________
>>>>>>> Amps mailing list
>>>>>>> Amps@contesting.com
>>>>>>> http://lists.contesting.com/mailman/listinfo/amps
>>>>>>>
>>>>>> _______________________________________________
>>>>>> Amps mailing list
>>>>>> Amps@contesting.com
>>>>>> http://lists.contesting.com/mailman/listinfo/amps
>>>>>>
>>>>> _______________________________________________
>>>>> Amps mailing list
>>>>> Amps@contesting.com
>>>>> http://lists.contesting.com/mailman/listinfo/amps
>>>>>
>>>>>
>>>>
>>>> _______________________________________________
>>>> Amps mailing list
>>>> Amps@contesting.com
>>>> http://lists.contesting.com/mailman/listinfo/amps
>>>
>>>
>>
>
>
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|