Understanding Stray Voltage

[HickoryFarms]

I (believe) I have seen two prong devices that used a coupling capacitor to use the ground afforded by the neutral. I could be very wrong about that.

That switch is very tight and congested, so I don't like the idea of messing with it again. But I wish I had taken some measurements while the three circuits in the barn had the neutrals off.

So, IS a ground rod, code for a sub panel? One, or more?

I believe it is, unless you have a steel pipe going underground from the sub panel, then that can count as your ground. Codes definitely vary locally.

 

[Industrial Toys]

So, just to be clear.

You can't bond the neutral and electrical ground at the sub panel. And I am guessing that it's a safety concern that if you broke the neutral, the ground conductor. would assume that role.

So taking things one step farther. If a device in the barn had neutral and electrical ground tied together, that would be the same as it being bonded at the panel, but would not cause the problems being experienced. Or?

 

[HickoryFarms]

So, just to be clear.

You can't bond the neutral and electrical ground at the sub panel. And I am guessing that it's a safety concern that if you broke the neutral, the ground conductor. would assume that role.

So taking things one step farther. If a device in the barn had neutral and electrical ground tied together, that would be the same as it being bonded at the panel, but would not cause the problems being experienced. Or?

Neutrals get grounded. In my sub-panels, the neutrals are going to lugs affixed to the panel (they aren’t isolated lugs like the phases), and the panel is grounded. The stray voltage on a neutral gets sent to earth.

 

[aczlan]

Neutrals get grounded. In my sub-panels, the neutrals are going to lugs affixed to the panel (they aren’t isolated lugs like the phases), and the panel is grounded. The stray voltage on a neutral gets sent to earth.

That is not correct per the current NEC. The most recent NEC requires that any sub-panels have the neutrals isolated and the only place where the neutrals and the grounds are connected is at the first is connection point (which is generally your primary breaker panel).
Hence, per the current NEC you should have two hots, a neutral and a ground going from the main panel to any and also panels including sub-panels in remote buildings.

Aaron Z

 

[JPRambo]

If a device in the barn had neutral and electrical ground tied together
If this was true you would be replacing fuses when the device was turned on.
What is in the barn that is connected to this panel? Fluorescent lights? Outlets used for?

 

[Doofy]

Noticed a tingle when barefoot on the concrete garage floor (kids and dog actually told me this). The kids hollered and the dog wouldn't even go in. I went thru the panel and all the lighting fixtures and receptacles to no avail. Finally, tracked the problem down to the garage door opener. There were a couple of small lighting arrestor type small capacitors (or something) that had one blown. I cut them both off and no more tingle.

 

[JPRambo]

Glad you found the problem.

 

[teejk]

That is not correct per the current NEC. The most recent NEC requires that any sub-panels have the neutrals isolated and the only place where the neutrals and the grounds are connected is at the first is connection point (which is generally your primary breaker panel).
Hence, per the current NEC you should have two hots, a neutral and a ground going from the main panel to any and also panels including sub-panels in remote buildings.

Aaron Z

You are referring to "single point grounding" (meaning all grounds come back to the primary ground at the service entrance...usually the main breaker box)? It's a confusing concept I guess. E.g. satellite TV is supposed to come back to that point but if you ask any installer he'll ignore you while he sinks his separate ground rod (cheaper than running 6ga wire I guess).

 

[HickoryFarms]

That is not correct per the current NEC. The most recent NEC requires that any sub-panels have the neutrals isolated and the only place where the neutrals and the grounds are connected is at the first is connection point (which is generally your primary breaker panel).
Hence, per the current NEC you should have two hots, a neutral and a ground going from the main panel to any and also panels including sub-panels in remote buildings.

Aaron Z

I’m honestly not familiar with too much residential codes. Relying on one single connection for your ground doesn’t make much sense to me. But if that’s what it is......

If a device in the barn had neutral and electrical ground tied together
If this was true you would be replacing fuses when the device was turned on.
What is in the barn that is connected to this panel? Fluorescent lights? Outlets used for?

Every 3rd pole we set, the neutral gets grounded to the earth. I would presume most utilities throughout the country have a WYE, multi grounded system. The same goes for our secondary voltages (the stuff that powers your house), the neutrals are grounded.

 

[John Fitzgerald]

See "step potential".