In article ,
Charles Schuler wrote:

wrote in message
oups.com...
I installed a subpanel when I switched from an electric stove to gas. I
used the 40A 220V breaker that formerly served the stove to power the
sub panel. The cable is #4 with two conductors and a ground. I have 6-
15 amp breakers in the panel providing branch circuits for my kitchen
and other areas of my house. The grounds and neutrals all share the
common bus bar in the sub panel. Everything has worked fine for years
now. Can someone explain why I read that ground and neutral are to be
isolated in the sub panel? Please don't answer because of the NEC since
that does not explain why. What is the risk of my current situation?

The neutral (white) is a return ... it carries the same current as the hot
wire (black). The ground wire is a non current-carrying safety wire (often
bare copper). The purpose of the ground wire is to reduce voltages in the
case of lightning or an accident (wires falling across other wires outside
of your home and raising the voltage with respect to ground to a dangerous
level). The ground wire only conducts current in the case of a fault.
Ground fault circuit interrupters need the ground wire to detect such faults
and open the circuit when they occur.

People are often shocked and even electrocuted with voltages with respect to
ground ... one is standing on a wet basement floor ... one is touching a
faucet ... one is in the tub or shower. The voltage with respect to ground
is the big issue here (for safety reasons).

An ungrounded electrical system in your home would allow voltages to rise to
thousands of volts above ground and fry you if you happened to be grounded
(in a tub or standing on a wet concrete floor).



Are there one or more books that actually coverf
*this* kind of stuff, ie that's being discussed in
*this* thread?

Not some home-improvement book you might find at HD,
but something that really, tutorially, gets down to
the depth of *this* stuff, this "more complex" stuff
than you usually see covered in the home-improvement-style
electrical-books.

Something so that when you finish a subject, you really
understand it, not so that you can merely "do" some
home-job, but even would let you (correctly!, and usefully)
contribute to eg this current thread.

Ideas?

Thanks!

David


PS: eons ago I took some EE courses in college, but of course
that knowledge was pretty useless for this current subject.