[Amps] NEC-think.

[R.Measures]

On Jan 5, 2006, at 9:38 PM, m.ford wrote:

>
> ----- Original Message ----- From: "R.Measures" <r at somis.org>
> To: "John Popelish" <jpopelish at rica.net>
> Cc: <Amps at contesting.com>
> Sent: Friday, January 06, 2006 12:15 AM
> Subject: Re: [Amps] NEC-think.
>
>
>
> On Jan 5, 2006, at 2:08 PM, John Popelish wrote:
>
>> R.Measures wrote:
>>
>>> Without a ground/bond wire wouldn't connecting the Neutral wire to 
>>> the
>>> metal enclosure hold the enclosure to a safe potential until the
>>> breaker trips?
>>
>> The neutral carries load current,
>
> •   In a 240v appliance, why would it?
>
>>  so it may have some voltage drop at
>> the appliance end, compared to the end at the power panel.  And if it
>> ever goes high resistance, then the moment any load is connected to
>> it, it has full line voltage on it.  So a single failure (open
>> neutral) would produce a shock hazard if the case were attached to it,
>> the moment the appliance was turned on (a moment someone is likely to
>> be touching the case, also).
>
>> •  For a shock hazard to exist, the person would also need to be
>> grounded.  The Neutral wire on the 240v outlet in my radio room is
>> #6-ga.  What would make the resistance of the Neutral go high and
>> simultaneously connect one Line wire to the enclosure?
>
> Rodents?

Rodents like the taste of white wiring but hate the taste of green 
wiring?  A rodent that can chew through 6-gauge will probably require 
the use of my 12-gauge.

> knaw.  Lightning?  Maybe.  But you're toast anyway.
> How about a tree on the service drop ripping the neutral open right
> through the wall and twistin the legs to bare metal in the box?
> Hey. It could happen.

We have underground wiring, but how about a Richter 9.8 'quake?
>
> Mike k1ern
>
>>
>> The safety ground never carries current under normal conditions, so it
>> take two failures (hot faulted to metal case and open ground
>> conductor) to produce an unsafe condition.
>>
>
> Richard L. Measures, AG6K, 805.386.3734.  www.somis.org
>
>
>
>

Richard L. Measures, AG6K, 805.386.3734.  www.somis.org