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Old 02-15-2012, 07:12 PM   #91
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Having proper grounding causes the breaker to trip if the hot shorts with the ground. The breaker will still trip if you overload the circuit or the hot shorts with the neutral.

Now if you want a good example of the importance of the ground, think of an overhead light in a bathroom with a metal pull string. In both cases the installer was sloppy and nicked the hot's insulation causing it to short with the light's metal canopy.

Case 1: Properly grounded.
- The circuit is now complete from the hot back through the ground to the panel. There's barely any resistance, so the breaker trips cutting off power. End of story.

Case 2: No ground
- Without a ground, the metal of the light remains hot, but nothing completes the circuit. In fact, the light will still work properly. Now image a poor guest gets out of the shower and goes to turn off the light before leaving the bathroom. This guest also took a long enough shower that there's enough moisture to electrically connect his feet to a metal water pipe going through the floor. When the guest grabs the pull chain, he'll complete a circuit going back to ground through the metal pipes. Now a wet human has a resistance in the 1,000 Ohm range (taken from the interwebs so don't hold me to that number). Now using V=IR, we find that our poor guest now has 0.120 A running through them. Most circuits are more than 0.120 A from capacity. Additionally, many circuit breaker will allow the current to go over capacity for short periods of time (needed for motors). Thus our poor guest gets electrocuted and circuit breaker doesn't give a hoot.


Last edited by a_lost_shadow; 02-15-2012 at 07:14 PM. Reason: who has a shower in their bedroom?
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Old 02-16-2012, 01:41 AM   #92
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Originally Posted by jhack836 View Post
one quick guestion. you guys say for the breaker to trip i need it to be grounded. how did things work back in the day or even some houses today that arent properly grounded? the home owner just taking a risk?>
That's very close to correct. But what is existing cannot readily be changed. However when things are added and wiring changes made to ungrounded wiring you, in most cases, must bring these changes up to current code standards. Nothing is perfect and completely safe. Over time electrical systems have undergone improved safety for design and installations. After all that really is what the NEC is written for .... a book of code that sets forth the standards for minimum safety requirements in electrical installations.

Electrocutions of humans in single family homes was quite alarming in the older un-grounded wiring design. Then the code making panels (CMP's) required the equipment ground wire, then gfci came along in the 80's, then in 1996 they did away with bonding neutral and ground for range and dryer 3 wire 120/240 volt circuits and electrocutions have fallen dramatically. Over the past 3 code cycles AFCI has taken the forefront for safety improvements. These are protecting property and loss of human life from fire by tripping out afci breakers when parallel or series arcing occurs in the wiring, thereby preventing a fire. So its been an ever evolving process to improve human safety and property protection.
" One nice thing about the NEC articles ... you have lots of choices"


Last edited by Stubbie; 02-16-2012 at 01:44 AM.
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Old 02-16-2012, 07:12 AM   #93
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fan wiring

That's a good idea. Run your power into and out of the outlet to the switch. You will then have a hot (black) and a white(neutral) at your switch(while your outlet will remain hot at all times.

Run a 14-2 or 14-3 to your fan from your switch. Wirenut the whites(neutrals). And the black from your outlet will go to the feed side of the switch. If you use 14-2 then the black to the fan goes to the other terminal on your switch.

If you use a three conductor (14-3) the outlet black conductor goes to the feed side of the switch and the red and black go on the load side of a 2 switch device on a single yoke.

If you use 14-2 the fan and light will be controlled by the switch. If you go with the 14-3 then you will have independent control of the fan and light.
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Old 06-03-2012, 08:54 PM   #94
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just a fyi i just found out. i bought a tester to test my outlets. and it said it was correct. i remember people on hear saying the outlet wasnt grounded correctly? or where they saying my switch and fan are not grounded correctly? the outlet is reading correct, is there a way to test switches and lights/fans or no?


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