[BC] Electrical Code

[Milton R. Holladay Jr.]

Yes, there are 5 fuses in the bottom, 2 of them on the 120 volt circuit:
oddly, one is in the neutral. It takes a 6  or 8 inch run of wire to cannect
the 120 V single fuse to the 3phase.(Needs a wire to the breaker panel for
the neutral.)
(Pls note that the "wild leg" in any 240v delta is 208volts to neutral so it
obviously can't be used for 120.     ~208 if open, wildly varying,  as you
said.)
I despise having small stuff mounted on the bottom of any xmtr, but in my
experience, dropped hardware is more highly attracted than  tools; the
smaller it is, the more likely to fall.............<g>
M
----- Original Message ----- 
From: "Davis, Jack L. (KTXL)" <Jldavis at tribune.com>
To: <broadcast at radiolists.net>
Sent: Friday, October 21, 2005 12:35 PM
Subject: [BC] Electrical Code


>
> <Message: 12
> <Date: Thu, 20 Oct 2005 21:56:29 -0400
> <From: "Milton R. Holladay Jr." <miltron at mindspring.com>
> <Subject: Re: [BC] Re: Saving Your Own Life
> <To: "Broadcast Radio Mailing List" <broadcast at radiolists.net>
> <Message-ID: <043101c5d5e2$a878a050$68b1f7a5 at miltron>
> <Content-Type: text/plain; charset="iso-8859-1"
>
> <One of the most hazardous, stupid xmtrs that most of us have encountered
is
> <the FM-20 and its smaller brothers which have not only the 3 phase
circuit,
> <but a separate 120 volt circuit, waiting to bite you. Any that I have had
> my
> <hands in now have the 120V tied to one of the 120V legs of the 3 phase,
so
> >that when it's off, it's ALL OFF !
> <M
>
> This does not meet code, but for reasons other than previously discussed.
> The three phase Wye connected power is actually 208 volts leg to leg and
120
> volts to neutral.  So it is perfectly legitimate to use any leg to neutral
> for a single phase load.  The code problem gets to be one of fusing, the
> three phase is most likely fused (or circuit breaker) at a high value and
> the wiring on the single phase load is not capeable of that kind of
current.
> If you fuse the single phase load at a proper value there should not be a
> problem.  If the three phase is Delta connected (Not common anymore) then
> the voltage is 240 volts leg to leg and one of the leg to leg connections
is
> normally center tapped to form the neutral and 120-0-120 for single phase
> load.  Either end of the center tapped transformer winding to neutral is
120
> volts and is usable the third leg (often reffered as the "wild leg") can
not
> be used to neutral as it varys wildly depending on the load and current
> unbalance.
>
> Is the FM-20 the one with the ceramic fuse holder on the floor of the
> cabinet?  The one that attracts every dropped tool in a 5 foot radius?
>
>
> Jack Davis
> K6YC