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Electrical Wiring FAQ (Part 1 of 2)
Section - Grounding electrode system

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Top Document: Electrical Wiring FAQ (Part 1 of 2)
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	Note that full coverage of how to install a grounding electrode
	system is well beyond the scope of this FAQ.  The comments made
	here are primarily so that the reader understands what it is
	for, and some of its characteristics.

	The grounding electrode system is a method by which the neutral
	and grounding conductors are connected to the common "earth"
	reference.  The connection from the electrical system to the
	grounding system is made in only one place to avoid ground
	loops.

	The grounding electrode system is _not_ intended to carry much
	current.  Ground faults (Ie: hot to grounded case short) are
	conducted down the ground wire to where it is interconnected
	with the neutral and hopefully the breaker/fuse trips.  The
	grounding electrode does not participate in such a situation.
	While the conductors involved in this are relatively large, they're
	sized for lightning strikes and other extremely short duration
	events.  The grounding electrode system is specifically _not_
	expected to have enough conductivity to trip a 15A breaker.

	The grounding electrode often has a moderately high
	resistance.  For example, according to the NEC, an acceptable
	ground electrode system may have 25 ohms of resistance - only
	5A at 120V, not enough to trip a 15A breaker.

	A grounding electrode system usually consists of a primary
	grounding electrode, plus possibly a secondary electrode.  A
	primary electrode can be (if in direct contact with the earth):
	10' of ground rod.  10' of well casing or metallic water pipe
	(must be connected within 5' of pipe entrance to house).  20'
	of copper wire buried in the bottom of the footings.  A
	secondary electrode will be required if the primary is a water
	pipe or (NEC) if the primary electrode is >25 ohms to the
	dirt.

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
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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
Robert
Report this comment as inappropriate
Sep 11, 2014 @ 6:18 pm
Someone wrote this:
"Don't bother asking in Quebec - DIY wiring is banned throughout
the province."

The statement above is not true.
You can do anything you want as long as you follow the electrical code... just like in any other province.
Not following the code may not technically make you unsafe in the real world, but it may nullify you insurance claims if your house burns down because of your sloppy work. If you're not sure, get an expert to sign off on it. ;-)

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Top Document: Electrical Wiring FAQ (Part 1 of 2)
Previous Document: What's the purpose of the ground prong on an outlet, then?
Next Document: Bonding requirements

Part1 - Part2 - Single Page

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Send corrections/additions to the FAQ Maintainer:
clewis@ferret.ocunix.on.ca (Chris Lewis)





Last Update March 27 2014 @ 02:11 PM