Michael Pardee wrote:
> "Nick Bourne" <"nabourne at tpg.com.au"> wrote in message
> news:468251e1@dnews.tpgi.com.au...
>> Sorry I come from the criminal colonies were the British taught us to
>> speak. I think it comes from the original DC power grid where you got one
>> wire in and 6 foot steel rod driven into the earth out the back. I can't
>> get my head around the whole AC wiring thing of active and neutral. If you
>> touch either it give you a shock, can't see what's so neutral about it.
>>
> I'm not sure how wiring standards are there, but here in Yank-land the
> modern standard uses three wires for single phase (120 volt) wiring. Only
> one, the "hot" lead (I think there's a formal name for it but it isn't
> coming to mind), will produce a shock under normal conditions. The other
> two, neutral and ground (safety ground), are connected together at the power
> distribution point - in homes and similar, that's the circuit breaker panel.
> The current in the hot and neutral wires must balance; ground current
> indicates a fault.
>
> It is never wise to bet one's life on it, though. At work we recently began
> auditing the low voltage wiring in our substations (I work for an electric
> utility) and found some amazing sorts of miswiring. And recently my wife and
> I stayed in a hotel room (a mid-scale chain hotel) where turning on the hall
> light tripped the GFI breaker in the bathroom. Hmm....
>
> Mike
>
>
>
I'm not sure exactly how its wired here most of our houses have an earth
pole and two wires going out to the pole for single phase power, but it
seems kind of strange to have the earth hooked up to the neutral. We
run 240v so it might be different. what the point of the earth if its
connected to the neutral. it seems to me that it is a possible way of
getting zapped if any other appliance in the house is on. All I
definitely know is that we only fuse the active (Any scientific
instrument I have seen built in the states has a link across the second
fuse), and even if the power point is turn off you will still get zapped
if you stuck anything in it.

 

"Nick Bourne" <"nabourne at tpg.com.au"> wrote in message
news:46835409@dnews.tpgi.com.au...
> Michael Pardee wrote:
>> "Nick Bourne" <"nabourne at tpg.com.au"> wrote in message
>> news:468251e1@dnews.tpgi.com.au...
>>> Sorry I come from the criminal colonies were the British taught us to
>>> speak. I think it comes from the original DC power grid where you got
>>> one wire in and 6 foot steel rod driven into the earth out the back. I
>>> can't get my head around the whole AC wiring thing of active and
>>> neutral. If you touch either it give you a shock, can't see what's so
>>> neutral about it.
>>>
>> I'm not sure how wiring standards are there, but here in Yank-land the
>> modern standard uses three wires for single phase (120 volt) wiring. Only
>> one, the "hot" lead (I think there's a formal name for it but it isn't
>> coming to mind), will produce a shock under normal conditions. The other
>> two, neutral and ground (safety ground), are connected together at the
>> power distribution point - in homes and similar, that's the circuit
>> breaker panel. The current in the hot and neutral wires must balance;
>> ground current indicates a fault.
>>
>> It is never wise to bet one's life on it, though. At work we recently
>> began auditing the low voltage wiring in our substations (I work for an
>> electric utility) and found some amazing sorts of miswiring. And recently
>> my wife and I stayed in a hotel room (a mid-scale chain hotel) where
>> turning on the hall light tripped the GFI breaker in the bathroom.
>> Hmm....
>>
>> Mike
> I'm not sure exactly how its wired here most of our houses have an earth
> pole and two wires going out to the pole for single phase power, but it
> seems kind of strange to have the earth hooked up to the neutral. We run
> 240v so it might be different. what the point of the earth if its
> connected to the neutral. it seems to me that it is a possible way of
> getting zapped if any other appliance in the house is on. All I definitely
> know is that we only fuse the active (Any scientific instrument I have
> seen built in the states has a link across the second fuse), and even if
> the power point is turn off you will still get zapped if you stuck
> anything in it.
>
That would be different. 240 is what we call two-phase here but I suspect we
wire it differently. Our 240 is four wire: two "hot" phases, a neutral that
is 120V to either phase and at ground potential, and a safety ground. The
safety ground is what is normally expected to prevent shock from touching
appliances, although smaller devices (like power tools) are typically just
insulated from ground. (The standard is "double-insulated" but I don't see
what protects the user if both insulations fail.)

I confess I don't know anything about power standards outside the US.

Mike

 

"Nick Bourne" <"nabourne at tpg.com.au"> wrote in message
news:46835409@dnews.tpgi.com.au...
> Michael Pardee wrote:
>> "Nick Bourne" <"nabourne at tpg.com.au"> wrote in message
>> news:468251e1@dnews.tpgi.com.au...
>>> Sorry I come from the criminal colonies were the British taught us to
>>> speak. I think it comes from the original DC power grid where you got
>>> one wire in and 6 foot steel rod driven into the earth out the back. I
>>> can't get my head around the whole AC wiring thing of active and
>>> neutral. If you touch either it give you a shock, can't see what's so
>>> neutral about it.
>>>
>> I'm not sure how wiring standards are there, but here in Yank-land the
>> modern standard uses three wires for single phase (120 volt) wiring. Only
>> one, the "hot" lead (I think there's a formal name for it but it isn't
>> coming to mind), will produce a shock under normal conditions. The other
>> two, neutral and ground (safety ground), are connected together at the
>> power distribution point - in homes and similar, that's the circuit
>> breaker panel. The current in the hot and neutral wires must balance;
>> ground current indicates a fault.
>>
>> It is never wise to bet one's life on it, though. At work we recently
>> began auditing the low voltage wiring in our substations (I work for an
>> electric utility) and found some amazing sorts of miswiring. And recently
>> my wife and I stayed in a hotel room (a mid-scale chain hotel) where
>> turning on the hall light tripped the GFI breaker in the bathroom.
>> Hmm....
>>
>> Mike
> I'm not sure exactly how its wired here most of our houses have an earth
> pole and two wires going out to the pole for single phase power, but it
> seems kind of strange to have the earth hooked up to the neutral. We run
> 240v so it might be different. what the point of the earth if its
> connected to the neutral. it seems to me that it is a possible way of
> getting zapped if any other appliance in the house is on. All I definitely
> know is that we only fuse the active (Any scientific instrument I have
> seen built in the states has a link across the second fuse), and even if
> the power point is turn off you will still get zapped if you stuck
> anything in it.
>
That would be different. 240 is what we call two-phase here but I suspect we
wire it differently. Our 240 is four wire: two "hot" phases, a neutral that
is 120V to either phase and at ground potential, and a safety ground. The
safety ground is what is normally expected to prevent shock from touching
appliances, although smaller devices (like power tools) are typically just
insulated from ground. (The standard is "double-insulated" but I don't see
what protects the user if both insulations fail.)

I confess I don't know anything about power standards outside the US.

Mike

 

"Nick Bourne" <"nabourne at tpg.com.au"> wrote in message
news:46835409@dnews.tpgi.com.au...
> Michael Pardee wrote:
>> "Nick Bourne" <"nabourne at tpg.com.au"> wrote in message
>> news:468251e1@dnews.tpgi.com.au...
>>> Sorry I come from the criminal colonies were the British taught us to
>>> speak. I think it comes from the original DC power grid where you got
>>> one wire in and 6 foot steel rod driven into the earth out the back. I
>>> can't get my head around the whole AC wiring thing of active and
>>> neutral. If you touch either it give you a shock, can't see what's so
>>> neutral about it.
>>>
>> I'm not sure how wiring standards are there, but here in Yank-land the
>> modern standard uses three wires for single phase (120 volt) wiring. Only
>> one, the "hot" lead (I think there's a formal name for it but it isn't
>> coming to mind), will produce a shock under normal conditions. The other
>> two, neutral and ground (safety ground), are connected together at the
>> power distribution point - in homes and similar, that's the circuit
>> breaker panel. The current in the hot and neutral wires must balance;
>> ground current indicates a fault.
>>
>> It is never wise to bet one's life on it, though. At work we recently
>> began auditing the low voltage wiring in our substations (I work for an
>> electric utility) and found some amazing sorts of miswiring. And recently
>> my wife and I stayed in a hotel room (a mid-scale chain hotel) where
>> turning on the hall light tripped the GFI breaker in the bathroom.
>> Hmm....
>>
>> Mike
> I'm not sure exactly how its wired here most of our houses have an earth
> pole and two wires going out to the pole for single phase power, but it
> seems kind of strange to have the earth hooked up to the neutral. We run
> 240v so it might be different. what the point of the earth if its
> connected to the neutral. it seems to me that it is a possible way of
> getting zapped if any other appliance in the house is on. All I definitely
> know is that we only fuse the active (Any scientific instrument I have
> seen built in the states has a link across the second fuse), and even if
> the power point is turn off you will still get zapped if you stuck
> anything in it.
>
That would be different. 240 is what we call two-phase here but I suspect we
wire it differently. Our 240 is four wire: two "hot" phases, a neutral that
is 120V to either phase and at ground potential, and a safety ground. The
safety ground is what is normally expected to prevent shock from touching
appliances, although smaller devices (like power tools) are typically just
insulated from ground. (The standard is "double-insulated" but I don't see
what protects the user if both insulations fail.)

I confess I don't know anything about power standards outside the US.

Mike