[time-nuts] AC Connector On HP 5061B

Mike Naruta AA8K aa8k at comcast.net
Thu Oct 2 14:10:43 EDT 2008

Basically, we get ours from a 230 Volt,
center-tapped transformer secondary.
The center tap is also earthed.  We can
connect 115 Volt appliances between either
end of the transformer and center-tap "neutral".
Higher-current appliances connect to both
ends to get the full 230 Volts.

The neutral is bonded to the earth connection
at the mains panel.

Ground Fault Interrupters (GFI) monitor
the current flow in the "hot" and neutral
conductors.  Any imbalance indicates a
current flow on the earth conductor and
the GFI disconnects the circuit to remove
a shock hazard.

Interesting things happen when the neutral
conductor between the mains panel and the
utility transformer secondary has high
resistance.  Instead of the voltage being
the same on both "hot" leads, the voltage
is divided proportionately to the load
resistance.  One "hot" lead can be at,
say, 30 Volts, while the other "hot" lead
is at 200 Volts.  This can be exciting.

Mike - AA8K

David C. Partridge wrote:
> That critically depends what country you are in.
> In the UK you can normally safely connect yourself between neutral and
> earth, as neutral is "always" bonded to earth at the sub-station.   There
> may be a few volts on neutral due to phase imbalance in the three phase
> supply and how far you are from the sub-station, but normally that's not a
> problem.   I really wouldn't like to connect myself between live (nominal
> 230V over here) and neutral though!
> I don't know the wiring rules in US well enough to determine how "safe" this
> would "over there".
> Dave

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