[Amps] TL922 Power Plugs

[Jim Carr]

I got called out on a service call years ago to a mobile home that was 
acting weird. It only had lights when the furnace came on and then very dim. 
Turns out it was fed from a panel that somebody boot legged in with a fused 
neutral. The fuse blew and the lights were completing the circuit through 
the furnace elements. When the GFCI came out it was mandated by the federal 
government. It took about three code changes (nine years) before the 
manufacturers finally perfected a working one. But it was so sensative that 
more than 20 feet of wire would trip it so the contractors used GFCI outlets 
instead of breakers. They are still used almost exclusively in residential 
wiring. But now days mostly due to cost. The way they work is by sensing the 
current flowing on the hot leg and the neutral. If they are not equal then 
the return path has found a secondary path, possibly you. Ground rods
only establish a ground potential at that point. The neutral is close to 
that potential at the service main. depending on soil conductivity there can 
be quite a difference as you get out from the service main. I burned the 
gimmlet off a ship bit 35 years ago when i touched a cast iron sewer stack 
with it. There was nothing wrong with the drill, cords or the service. I was 
a 120 feet out and the measured difference between the equipment ground in 
the cord and the pipe was 103 volts. Now days most good contractors use 
spider boxes out on the project with GFCI outlets in them.
Jim
N7FCF
----- Original Message ----- 
From: "Alex Eban" <alexeban at gmail.com>
To: "'Gary Schafer'" <garyschafer at comcast.net>; <dezrat1242 at yahoo.com>; 
<amps at contesting.com>
Sent: Tuesday, November 03, 2009 11:55 PM
Subject: Re: [Amps] TL922 Power Plugs


> This is not detrimental if, that is, you have a ground fault interrupter
> AFTER the point where the wires are strapped together. Otherwise it won't
> activate and save your skin!
> Alex 4Z5KS
>
> -----Original Message-----
> From: amps-bounces at contesting.com [mailto:amps-bounces at contesting.com] On
> Behalf Of Gary Schafer
> Sent: Wednesday, November 04, 2009 6:35 AM
> To: dezrat1242 at yahoo.com; amps at contesting.com
> Subject: Re: [Amps] TL922 Power Plugs
>
>
>
>> -----Original Message-----
>> From: amps-bounces at contesting.com [mailto:amps-bounces at contesting.com]
>> On Behalf Of Bill, W6WRT
>> Sent: Tuesday, November 03, 2009 10:04 PM
>> To: amps at contesting.com
>> Subject: Re: [Amps] TL922 Power Plugs
>>
>> ORIGINAL MESSAGE:
>>
>> On Tue, 3 Nov 2009 21:49:13 -0500, "Carl" <km1h at jeremy.mv.com> wrote:
>>
>> >
>> >The danger is some big hungry rat or an evil person will remove your
>> neutral
>> >wire which will return you to the dark days of a 2 wire non polarized
>> >outlets and plugs. Just think, you may only have a one wire system
>> >then
>> and
>> >will have to carefully reach around until your hand finds the missing
>> path.
>> >How some of us survived to talk about them confounds the rules makers.
>>
>> REPLY:
>>
>> That wasn't my question. Please forgive me if I wasn't clear enough.
>>
>> My question was this:  I understand why it is necessary to bond ground
>> and neutral together at the service box, but I don't understand why it
>> is forbidden to bond them together at the appliance.
>>
>> There must be a scenario which causes danger but I just can't imagine
>> what it is.
>>
>> 73, Bill W6WRT
>
> If they are both bonded at the appliance both will carry neutral currents.
> That can raise the appliance case above ground due to voltage drop in the
> cable. Should neutral and ground become open somewhere in their path that
> would put full line voltage on the appliance case.
>
> With neutral never connected to the appliance case any or all conductors 
> can
> become open and no voltage will appear on the case unless there is a short
> between a hot line and case and the ground wire becomes open.
>
> 73
> Gary  K4FMX
>
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