booting and 11/44 via tu58 sim?

[Bjørn Vermo]

On 21 Jun, 2005, at 12:35, Ethan Dicks wrote:

> On 6/21/05, Paul Koning <pkoning at equallogic.com> wrote:
>> If your boxes are plugged into grounded outlets, as they should be,
>> then there should NOT be large currents flowing through frame ground
>> cables.  If you do observe that, track down the fault before someone
>> gets hurt.
>
> The key word is "should"... If you get some ya-hoo who decides they
> can save a few $$$ and wire up an outlet... well... let's just say
> that the first homeowner's tool I bought was an outlet tester, and I
> found two outlets that had hot and neutral reversed...
>
> I worked at a place where the owner plugged a serial cable in between
> his PC and his Mac, and  he roached the Mac serial port because of the
> same problem.  He had all the outlets tested and fixed, but he also
> made a proclaimation - no computers were to be connected via serial
> cables unless they pulled their power from the same wall outlet.  A
> bit inflexible, but guaranteed not to have a mismatch.

In Norway, you will not get mains-powered devices approved unless the 
chassis is isolated. Our AC wiring does not have any concept of 
"neutral", since both wires are supposed to be at the same potential 
relative to ground. That way, everybody learns to be careful.

I can see the economics of using four-wire Y-connected three-phase 
transformers instead of three wire plus earth delta-connected, but I 
have also seen the frying potential when some genius takes for granted 
that one of the power wires is supposed to be at ground potential.

The isolation transformer is your friend. Especially when it is also 
cleaning spikes and flywheeling over dips.

-- 
-bv