it's that damn breaker again

[kb3ouk]

nd the white  (or grounded conductor) through a toroid and if there is any difference (A mA or so) it trips. If any current flowing out of the Black (hot) wire does not return back through the white wire - then there is current flowing to ground somewhere and the GFI trips. If you have the grounded conductor (the white wire  touching ground anywhere in the rig or amp or in the wiring - you can have a problem.

The green wire is the grounding conductor and NEVER carries current except in the case of a line to ground fault - it is sized to trip the circuit breaker quickly.

Pat,  green is ground; white is neutral return.

73

Rob

I thought that there were times tatthe neutral was grounded in a piece of electronic equipment.
Shelby KB3OUK

[N4LTA]

Rob,

The NEC (National Electric Code) defines the following conductors and color codes in a grounded single phase power system

Black is the ungrounded conductor
White or natural gray is the grounded conductor
Green is the grounding conductor

Note grounded conductor and grounding conductor

The white - sometimes miscalled the neutral conductor is grounded at the service entrance  at a single point - AND NO WHERE ELSE.

This point is called the bonding point and the green grounding condutor originates at this point. At no other point in the system do the white grounded conductor and the green grounding conductor tie together - hence the system has a single point ground. The bonding point is grounded to the utility ground, the cold water pipe and any of several code defined grounding electrodes.

The black and white conductor are current carrying conductors - the green is not except in fault conditions.

The white or grounded conductor is always at bonded to ground - but at only one place - the bonding point - since it carries current - it is at ground potential only at the bond point and the farther down stream - the more potential difference you get from the white to the green wires. The green wire is always at ground potential because no current flows through it.

In a three phase grounded system - the phase wires are color coded depending on voltage and the grounded conductor is white or natural gray (always)

The above is pretty simple and is very much misunderstood - a grounding conductor is NEVER allowed to carry current.  I have witnessed many cases where the green wire was bonded in multiple points causing a multitude of problem from people thinking that the more "grounds" the better. In one case we measured over 20 MA of AC current flowing in the shield of a CCTV coax because multiple panels had bonding jumpers installed. That made the ground at the different coax connections at different voltage potentials. The result was that the video was almost totally blanked.

The IT folks are the very worst for misunderstanding ground systems and how they react to their computer systems.

BTW - A cap from "AC hot " to ground in a three wire cord might very well trip the GFI if it is large enough.  It only take a very small leakage current.

I have had it leak through me several times and trip the breaker with only a mild shock.

Pat
N4LTA

[kb3ouk]

That's why the neutral on the pole usually has a ground wire hooked to it.

[WA1GFZ]

True for lightning protection. The NEC wants any offset current to flow between the pole ground and the house single point ground so it doesn't distribute all over the building. It is OK to have multiple grounds as long as it only connects to the service ground at the single point ground. The single point ground is the safety ground in the breaker panel. My building inspector thought it would be a good idea to run an additional ground over to the water service and attach to both sides of the meter. Then I fessed up and told him I was a ham and showed him the #8 solid leads coming in with the 3/4 inch copper water that would become the shack ground. He thought it would be good to  tie them into the service ground lead.
I was surprised that he didn't want me to run a ground in from the meter when I asked about it.

[w8khk]

nd the white  (or grounded conductor) through a toroid and if there is any difference (A mA or so) it trips. If any current flowing out of the Black (hot) wire does not return back through the white wire - then there is current flowing to ground somewhere and the GFI trips. If you have the grounded conductor (the white wire  touching ground anywhere in the rig or amp or in the wiring - you can have a problem.

The green wire is the grounding conductor and NEVER carries current except in the case of a line to ground fault - it is sized to trip the circuit breaker quickly.

Pat,  green is ground; white is neutral return.

73

Rob

Rob, while you are correct in stating green is ground, and white is neutral return, Pat is also correct and accurate in the use of the terms "grounded" and "grounding".  These words are used extensively in the NEC manual.  

The neutral is bonded to the ground only at the service entrance.  Hence neutral is often referred to as the "grounded" conductor.   White, neutral, and grounded all refer to the same wire.

The green is used to bond the appliance to the ground, such that the appliance remains at ground potential if there is a short in the appliance, thus tripping the breaker instead of placing the appliance at a dangerous voltage with respect to ground.  Hence, it is commonly referred to as the "grounding" wire.  Green, ground, and grounding all refer to the same conductor.  I hope this helps to clarify the terminology.

EDIT:  My apologies, Pat.  I did not see your post on "page 2" clarifying the issue, thus my post is redundant!

I agree with your statement about IT folks not understanding power and grounding issues.  In my years with Hewlett Packard, I was certified to inspect and recommend updates to customer power to resolve issues with the larger computer systems, preferably prior to the installation.  Ground loops and noisy grounds were common causes of intermittent failures.  One of the things that alleviated many of these problems was the move to connecting peripherals with fibre optics rather than copper cables.  

[N3DRB The Derb]

got on last night - breaker tripping - I removed all grounds from the gear and no more breaker tripping,
but got a instant case of RF in the audio upon transmit. 

gonna try moving the matchbox so the feedline goes straight out of the wall. Right now it's got a 8ft run before it hits the outside.

[N4LTA]

Not to try to start a P match but this is a quote from Mike Holt's book on the NEC. Mike is THE authority on the NEC. I am a bit picky and I really don't have a problem using the term neutral as it is a very common practice and I probably use it myself but ...

"Author’s Comment: The electrical trade industry typically uses the term “neutral,” when referring to the white/gray wire. However, the proper
term for this conductor is “grounded conductor.”
Technically, it’s improper to call a “grounded conductor” a “neutral conductor” or “neutral wire” when it’s not truly a neutral conductor,
but this is a long-standing industry practice. For the purpose of this workbook this conductor will be called a grounded neutral conductor.
That should keep most people happy."

As I said Neutral is a common term and is often misused. The term neutral is defined by the IEEE as having equal potential to all other current carrying conductors. This is only the case in an exactly balanced three phase system with no harmonic loads.

I constantly have to deal with electrical contractors that don't know the difference between a neutral, a grounded conductor or a ground conductor and haven't a clue about neutral bonding - so I am a bit picky. In most states - there only has to be one licensed contractor for an electrical contractor business - even if it has 1000 employees. Doesn't make a lot of sense to me. The examination procedure is getting to be like the Ham exams - you can memorize the test and never understand the theory.

I am am EE with about 35 years experience and took the Masters exam several years ago. I studied for a couple of weeks working out problems and design practice.

When I took the test - I worked one simple design problem - the rest was nothing more than using the code book to find answers to questions like " how far can a telephone drop be located from a telephone service drop"?

Pat
N4LTA

[w8khk]

No contest here, Pat.  I could not have said it better than you did, and if I realized you already posted, I would not have added my comments.  We are fortunate to have posts from knowledgable authorities like yourself from which to learn! 
Your comments about the misuse of the term "neutral" bring "flashbacks" to my memory years back when many inspectors did not understand the theory or the code.  Thank you for your clarifications!

[N4LTA]

W8KHK

Your not far away. I am just up the road. I know exactly what you mean. Sounds like you may be in the electrical business too?

Pat
N4LTA

[WA1GFZ]

Derb,
Would it be possible to run a ground back to the panel and tie it into the station grounds? You may be setting up a loop causing the offset. Check to make sure no neutrals are tied to chassis ground.

[w8khk]

W8KHK

Your not far away. I am just up the road. I know exactly what you mean. Sounds like you may be in the electrical business too?

Pat
N4LTA

I looked up your call this morning.  Yes, you are almost a neighbor.  I am in Marietta, northwest of Atlanta.  I often travel up to Virginia to visit with friends.  Maybe next trip I can stop in for an eyeball QSO. 

I worked for Hewlett Packard from 1977, then Agilent Technologies (when they split off) from 1999 until retirement in 2006.  Initially I performed on-site service for the HP-3000 systems, and then specialized in site preparation in conjunction with sales and upgrades.  It was not always easy to convince customers to do the power and HVAC properly the first time, but those that did it right up-front were much happier with the overall reliability for years to come.  The most challenging were the remotes in the Bahamas and San Juan.  My work in Agilent was more a software engineering role, developing tools and processes to deploy and manage servers remotely on a world-wide scale.

[N3DRB The Derb]

Frank,

I'm going to call the homies at the electric place. I strongly suspect that I've got problems related to the wiring my former boss did when he finished the garage out. Think it's time to call in the pros and get it inspected and fixed.

I really dont need anymore grief, at least not any that I havent put upon myself.