Neutral Wire Questions
#1
Member
Thread Starter
Neutral Wire Questions
Okay...a few more ignorant questions to add to the pile.
1) If the neutral wire wasn't grounded, I assume that it would have the same 120 volt potential as the hot wire? (Thus the grounding is what makes the neutral wire, well, neutral).
2) If an outlet is in use, does the grounding matter at that point? (If I touched the "neutral" wire while in use, would I get a shock just the same as with the hot wire?)
Thanks...you pros inspire me.
1) If the neutral wire wasn't grounded, I assume that it would have the same 120 volt potential as the hot wire? (Thus the grounding is what makes the neutral wire, well, neutral).
2) If an outlet is in use, does the grounding matter at that point? (If I touched the "neutral" wire while in use, would I get a shock just the same as with the hot wire?)
Thanks...you pros inspire me.

#2
2) If an outlet is in use, does the grounding matter at that point? (If I touched the "neutral" wire while in use, would I get a shock just the same as with the hot wire?)
#3
Member
Thread Starter
So the neutral is not directly attached to one of the two hot supply lines coming into the house...?
#4
Some people have the mistaken idea that the 240 volts comes from two 120v supplies. It doesn't. The 240v is the power that is supplied to your house. The 120v come from using the center tap and one 240v leg.
All of the above applies to single phase power.
#5
No. The service from the power company is provided on three wires, hot-neutral-hot and the neutral is also grounded to the earth. The potential from either hot to the grounded neutral is 120V, the potential from hot to hot is 240V.
A simplified way of thinking about this is to imagine the grounded neutral at 0V, one of the hots is +120V and the other hot is -120V. Each is 120V from the ground, but 240V from each other. In reality A/C is more complex than that, but it is conceptually valid.
Hot |<----- 120V ----->| Neutral |<----- 120V ----->| Hot
In most electrical systems (all residential systems) the neutral is connected to the earth to provide some safety as it reduces the possibility of being shocked.
A simplified way of thinking about this is to imagine the grounded neutral at 0V, one of the hots is +120V and the other hot is -120V. Each is 120V from the ground, but 240V from each other. In reality A/C is more complex than that, but it is conceptually valid.
Hot |<----- 120V ----->| Neutral |<----- 120V ----->| Hot
In most electrical systems (all residential systems) the neutral is connected to the earth to provide some safety as it reduces the possibility of being shocked.
#6
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Here's my attempt at explaining the neutral. please pardon my artistry.

Here's a transformer, like the one coming from your power company to your home's breaker panel. If you look at your lines atop your house, you will see 3 wires coming in (two hots and a neutral). Sometimes there's 4 wires, which contains the ground wire. This is another topic.
Between points A & B in the first image, there will be 240v. note that this is a two wire system, providing only 240v, and ther's no neutral.
In the second image, again between a & b, there's 240v, but between either a & c or b & c, there's 120v.
"C" is the center tap (exactly center in the transformer windings) providing a point for 120v. If the center tap wire were to be located closer to point "a", then a different (lower) potential could be read between points "a" and "c". Likewise, a different (higher) potential would be found between "c" and "b".

Here's a transformer, like the one coming from your power company to your home's breaker panel. If you look at your lines atop your house, you will see 3 wires coming in (two hots and a neutral). Sometimes there's 4 wires, which contains the ground wire. This is another topic.
Between points A & B in the first image, there will be 240v. note that this is a two wire system, providing only 240v, and ther's no neutral.
In the second image, again between a & b, there's 240v, but between either a & c or b & c, there's 120v.
"C" is the center tap (exactly center in the transformer windings) providing a point for 120v. If the center tap wire were to be located closer to point "a", then a different (lower) potential could be read between points "a" and "c". Likewise, a different (higher) potential would be found between "c" and "b".