Get your HBT Growlers, Shirts and Membership before the Rush!


Home Brew Forums > Home Brewing Beer > Electric Brewing > 240V 3-wire drier ground/neutral confusion
Reply
 
LinkBack Thread Tools
Old 12-16-2011, 10:58 PM   #11
passedpawn
Waste Allocation Load Lifter - Earth Class
HBT_MODERATOR.png
Feedback Score: 0 reviews
 
passedpawn's Avatar
Recipes 
 
Join Date: Apr 2009
Location: ☼ Clearwater, FL ☼
Posts: 19,895
Liked 3724 Times on 2288 Posts
Likes Given: 3223

Default

Quote:
Originally Posted by Walker View Post
Look in your main panel. Neutral and ground are bonded together. Any where were you had connected something to neutral you have also connected to ground.
I'm well aware. Easier to ohm the outlet than remove the cover of my panel, but right.

If the OP has a 120 device in his rig, and he ties it to the neutral coming from the spa panel, how does that current get back to the panel? If it returns through the neutral to the spa panel, and that also serves as the safety ground, then the panels potential will rise when there is current on that neutral. It's likely that I'm missing something here.
__________________
Am I Insane or do I really see Heaven in Your Eyes?
passedpawn is offline
 
Reply With Quote Quick reply to this message
Old 12-16-2011, 11:09 PM   #12
Walker
I use secondaries. :p
HBT_LIFETIMESUPPORTER.png
Feedback Score: 0 reviews
 
Walker's Avatar
Recipes 
 
Join Date: Sep 2005
Location: Cary, NC
Posts: 11,236
Liked 89 Times on 79 Posts
Likes Given: 11

Default

Quote:
Originally Posted by passedpawn

I'm well aware. Easier to ohm the outlet than remove the cover of my panel, but right.

If the OP has a 120 device in his rig, and he ties it to the neutral coming from the spa panel, how does that current get back to the panel? If it returns through the neutral to the spa panel, and that also serves as the safety ground, then the panels potential will rise when there is current on that neutral. It's likely that I'm missing something here.
I guess I don't understand your concern maybe?

If neutral and ground are tied together all the way back to the main panel anyway... what's the difference?
__________________
Ground Fault Brewing Co.
Walker is offline
 
Reply With Quote Quick reply to this message
Old 12-16-2011, 11:18 PM   #13
passedpawn
Waste Allocation Load Lifter - Earth Class
HBT_MODERATOR.png
Feedback Score: 0 reviews
 
passedpawn's Avatar
Recipes 
 
Join Date: Apr 2009
Location: ☼ Clearwater, FL ☼
Posts: 19,895
Liked 3724 Times on 2288 Posts
Likes Given: 3223

Default

Quote:
Originally Posted by Walker View Post
I guess I don't understand your concern maybe?

If neutral and ground are tied together all the way back to the main panel anyway... what's the difference?
The OP asked if he needs a ground, I said yes, I was corrected. I'm all for the spa panel, but are you suggesting that there is no earth ground connected to it (only the neutral)?
__________________
Am I Insane or do I really see Heaven in Your Eyes?
passedpawn is offline
 
Reply With Quote Quick reply to this message
Old 12-16-2011, 11:42 PM   #14
Walker
I use secondaries. :p
HBT_LIFETIMESUPPORTER.png
Feedback Score: 0 reviews
 
Walker's Avatar
Recipes 
 
Join Date: Sep 2005
Location: Cary, NC
Posts: 11,236
Liked 89 Times on 79 Posts
Likes Given: 11

Default

Quote:
Originally Posted by passedpawn

The OP asked if he needs a ground, I said yes, I was corrected. I'm all for the spa panel, but are you suggesting that there is no earth ground connected to it (only the neutral)?
I am suggesting that neutral and ground are the same thing. If you have a 4 wire outlet and you start tracing the neutral and ground wires, they are both going to run side by side all the way back to the main panel were they are tied together.

The ground wire is not supposed to carry any current but the neutral does. I am suggesting splitting the neutral inside of a spa panel into two wires. 1 that is allowed to carry current and 1 that is not.
__________________
Ground Fault Brewing Co.
Walker is offline
 
Reply With Quote Quick reply to this message
Old 12-16-2011, 11:45 PM   #15
Walker
I use secondaries. :p
HBT_LIFETIMESUPPORTER.png
Feedback Score: 0 reviews
 
Walker's Avatar
Recipes 
 
Join Date: Sep 2005
Location: Cary, NC
Posts: 11,236
Liked 89 Times on 79 Posts
Likes Given: 11

Default

Oh and I was not correcting you. We were typing our responses at the same time. I had not even seen yours before I responded.

__________________
Ground Fault Brewing Co.
Walker is offline
 
Reply With Quote Quick reply to this message
Old 12-16-2011, 11:49 PM   #16
passedpawn
Waste Allocation Load Lifter - Earth Class
HBT_MODERATOR.png
Feedback Score: 0 reviews
 
passedpawn's Avatar
Recipes 
 
Join Date: Apr 2009
Location: ☼ Clearwater, FL ☼
Posts: 19,895
Liked 3724 Times on 2288 Posts
Likes Given: 3223

Default

Quote:
Originally Posted by Walker View Post
I am suggesting splitting the neutral inside of a spa panel into two wires. 1 that is allowed to carry current and 1 that is not.
I see.

Here's my point then:
  • If there is a 120V device in the rig, the return current will return on the neutral feeding the spa panel
  • Because there is current on that neutral, there will be a IR voltage rise at the spa panel and the rig; yes, the neutral is at ground potential at the breaker box, but not at the spa panel because of the current running on it
  • The "grounded" rig, because it relies ultimately on the neutral that feeds the spa panel, will not be a earth ground but at this elevated voltage because the IR voltage.

Do you see what I mean? What am I missing here?
__________________
Am I Insane or do I really see Heaven in Your Eyes?
passedpawn is offline
 
Reply With Quote Quick reply to this message
Old 12-17-2011, 12:03 AM   #17
Walker
I use secondaries. :p
HBT_LIFETIMESUPPORTER.png
Feedback Score: 0 reviews
 
Walker's Avatar
Recipes 
 
Join Date: Sep 2005
Location: Cary, NC
Posts: 11,236
Liked 89 Times on 79 Posts
Likes Given: 11

Default

Okay so at my house my main panel is on the wall in the garage. I had a 50 amp outlet installed 2 feet away from it. That outlet is fed by a gfci breaker.

Neutral and ground are tied together inside that panel next to my outlet.

I don't see the difference. I am not trying to be a jerk. I just really don't see the difference.

There is a 4 wire outlet. There is a short run of wire. Ground wire connects to a bus. Hot and neutral go through a breaker. And athen neutral is connected to the same bus as the ground.

__________________
Ground Fault Brewing Co.
Walker is offline
 
Reply With Quote Quick reply to this message
Old 12-17-2011, 12:14 AM   #18
passedpawn
Waste Allocation Load Lifter - Earth Class
HBT_MODERATOR.png
Feedback Score: 0 reviews
 
passedpawn's Avatar
Recipes 
 
Join Date: Apr 2009
Location: ☼ Clearwater, FL ☼
Posts: 19,895
Liked 3724 Times on 2288 Posts
Likes Given: 3223

Default

I brew behind my house, at least 100' from the breaker box in the garage. 240VAC. Assuming there is a 1 ohm resistance in the neutral wire, if used as a ground it would be at 10VAC if there was 10A running on it.

Sorry to split hairs, I'll go on my way now. Cheers!

__________________
Am I Insane or do I really see Heaven in Your Eyes?
passedpawn is offline
 
Reply With Quote Quick reply to this message
Old 12-17-2011, 12:15 AM   #19
P-J
HBT_LIFETIMESUPPORTER.png
Feedback Score: 0 reviews
Recipes 
 
Join Date: Mar 2010
Location: Charlotte, NC
Posts: 3,284
Liked 260 Times on 207 Posts
Likes Given: 459

Default

Quote:
Originally Posted by passedpawn View Post
I see.

Here's my point then:
  • If there is a 120V device in the rig, the return current will return on the neutral feeding the spa panel
  • Because there is current on that neutral, there will be a IR voltage rise at the spa panel and the rig; yes, the neutral is at ground potential at the breaker box, but not at the spa panel because of the current running on it
  • The "grounded" rig, because it relies ultimately on the neutral that feeds the spa panel, will not be a earth ground but at this elevated voltage because the IR voltage.
Do you see what I mean? What am I missing here?
You are not missing anything at all. Yes the neutral potential will be elevated a very small amount above 'earth' due to the voltage drop caused by the current draw on the conductor. Is that ANY different than the neutral/ground supplied to the average dryer installed in a home with a 3 wire electrical layout?? Same thing with a free standing kitchen range powered with a 50A circuit before about 2004. We are talking about a voltage drop of less than 1 volt.

BTW - there is a greater voltage difference than that between earth at the power company's transformer and earth in your home.

Another thing for you to ponder. You live on a farm and there is a barn on the property. You provide power to it using overhead wiring. Is that power run through 4 conductors? (2 for phase A & B of the 240V + 1 neutral + 1 ground? Never happened.!!! It is a 3 wire system and earth ground is developed at the destination location.
__________________
P-J is offline
 
Reply With Quote Quick reply to this message
Old 12-17-2011, 12:28 AM   #20
passedpawn
Waste Allocation Load Lifter - Earth Class
HBT_MODERATOR.png
Feedback Score: 0 reviews
 
passedpawn's Avatar
Recipes 
 
Join Date: Apr 2009
Location: ☼ Clearwater, FL ☼
Posts: 19,895
Liked 3724 Times on 2288 Posts
Likes Given: 3223

Default

Quote:
Originally Posted by P-J View Post
BTW - there is a greater voltage difference than that between earth at the power company's transformer and earth in your home.
I've a copper stake near the power's entry point that ensure's that any standing water around my brewery is the same as the power ground coming into my house. It's irrelevant what the power company is delivering from the pole. Right?
__________________
Am I Insane or do I really see Heaven in Your Eyes?
passedpawn is offline
 
Reply With Quote Quick reply to this message
Reply



Quick Reply
Message:
Options
Thread Tools


Similar Threads
Thread Thread Starter Forum Replies Last Post
Wire size for 240v extension cord? BigJim_inFLA Electric Brewing 9 09-28-2011 02:03 AM
Gauge of ground wire GRHunter Electric Brewing 12 05-25-2011 11:26 PM
3 wire 240v GFCI question thelorax121 Electric Brewing 25 03-30-2011 03:31 AM
Type of wire for 5500w 240v element thomashp Electric Brewing 14 03-04-2011 11:35 PM
240V with no neutral? Can I build a rig? magnj Electric Brewing 98 02-10-2011 05:03 PM



Newest Threads

LATEST SPONSOR DEALS