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Electrical Wiring FAQ (Part 1 of 2)
Section - What's the purpose of the ground prong on an outlet, then?

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Top Document: Electrical Wiring FAQ (Part 1 of 2)
Previous Document: What is the difference between a GFCI outlet and a GFCI breaker?
Next Document: Grounding electrode system
See reader questions & answers on this topic! - Help others by sharing your knowledge

	Apart from their use in electronics, which we won't comment on,
	and for certain fluorescent lights (they won't turn on without
	a good ground connection), they're intended to guard against
	insulation failures within the device.  Generally, the case of
	the appliance is connected to the ground lead.  If there's an
	insulation failure that shorts the hot lead to the case, the
	ground lead conducts the electricity away safely (and possibly
	trips the circuit breaker in the process).  If the case is not
	grounded and such a short occurs, the case is live -- and if
	you touch it while you're grounded, you'll get zapped.  Of
	course, if the circuit is GFCI-protected, it will be a very
	tiny zap -- which is why you can use GFCIs to replace
	ungrounded outlets (both NEC and CEC).

	There are some appliances that should *never* be grounded.  In
	particular, that applies to toasters and anything else with
	exposed conductors.  Consider:  if you touch the heating
	electrode in a toaster, and you're not grounded, nothing will
	happen.  If you're slightly grounded, you'll get a small shock;
	the resistance will be too high.  But if the case were
	grounded, and you were holding it, you'd be the perfect path to
	ground...

User Contributions:

Dev
Report this comment as inappropriate
Dec 21, 2011 @ 12:00 am
In a fire protection circuit, circuts are shown witha no example 6,8,4etc. what it mean?these circuits are connected between smode detector,junction box etc
kevin
Report this comment as inappropriate
Dec 24, 2011 @ 12:12 pm
My daughter dropped a small necklace behind her dresser. The necklace crossed a plug terminal and shorted the receptacle.
I bought a new receptacle and installed the same. I still have no power I suspect there could be a bigger problem,this is aluminum wiring.
I've killed the breaker and call an electrician but am curious as to what happened.P.s. there is a dimmer switch on the same circuit.
dennis
Report this comment as inappropriate
Feb 24, 2012 @ 11:11 am
Regarding new construction wiring and running 12/2 and 14/3 wire in the same box.

I have multiple switches to lights. Ran 12/2 and 14/3 into switch box and inspector wrote correction needed.

What should I have done instead?

thank you
dennis
Robert
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Nov 26, 2012 @ 9:21 pm
Does a grounding electrode facilitate the operation of a OCPD, to clear a ground fault ?
@dennis
Report this comment as inappropriate
Mar 18, 2013 @ 10:10 am
Assuming you are installing two switches in a two switch box, you probably should have used 14/2 and 14/3 instead of replacing 14/2 with 12/2. If you are only installing one switch in a one switch box, you should only have one cable in the box.
P k
Report this comment as inappropriate
Jan 26, 2014 @ 10:10 am
I prefer to use nothing smaller than12 awg /the smallest sized wire on a circuit determines the allowable ampacity
Ex: 15 amp-14awg. 12awg-20amp only rule for thumb other factors such as continuous load,heating and others if you do not know the safe NEC rules then please call a qualified journeyman Electrician better be safe

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Top Document: Electrical Wiring FAQ (Part 1 of 2)
Previous Document: What is the difference between a GFCI outlet and a GFCI breaker?
Next Document: Grounding electrode system

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Last Update March 27 2014 @ 02:11 PM