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#155574 - 01/11/07 04:48 PM Re: Who can solve this problem? [Re: dllewel]
SirQuack Offline
shareholder in the making

Registered: 01/29/04
Posts: 13337
Loc: Iowa
The HT circuit is not sharing the neutral ground with any other circuit. All the outlets and switches on every circuit has the secondary ground (bare wire) twisted togethor and attached to the green screws. It is my understanding that this secondary ground can act like an antenna in certain instances, and really serves no purpose as most newer outlets/plugs incorporate the primary ground (white wire) with the larger spade on the plug, which can only be inserted one way.

Back in the day, when both spades were the same, this ground was required in the event someone reversed the hot(black) and primary ground (white). This would allow another path for the ground to take.

Anyway, the suggestion I had was to remove the secondary ground (bare wire) from the green screw on the outlet my AV equipment is plugged into. The alternative is to try to figure out which circuit is causing the problem or what appliace if any, is causing the problem. Sometimes if your ground rod is not deep enough (at least 6ft) you can have similar problems.

I'll see what I can find out, thanks for the help...

ps: Tom, the GE bulbs at Wally World are the same as at Menards, HD, etc... just cheaper.
_________________________
M80s-VP180-QS8s-EP600-2xEP350 Denon3808 Outlaw7700
M22-OWM22-VP100-Denon2805
Audio Nirvana

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#155575 - 01/11/07 04:56 PM Re: Who can solve this problem? [Re: SirQuack]
BrenR Offline
connoisseur

Registered: 12/10/03
Posts: 3602
Loc: Winnipeg MB Canada
Quote:

The HT circuit is not sharing the neutral ground with any other circuit. All the outlets and switches on every circuit has the secondary ground (bare wire) twisted togethor and attached to the green screws.


Am I reading that right? That the neutral (drop the term ground for clarity - it's a neutral wire) and the ground are connected at each wall box? If that's true, then you've got a serious issue. Your neutral should only be bonded (to ground) in ONE place in the house - at the main breaker panel. Even any other pony panels should have the neutral bonding strap removed. It's code.

And if I did read that wrong, and the neutrals aren't bonded at each box, then yes, all your neutrals are eventually connected together when they get back to the breaker panel. They're all screwed into the same neutral bar.

Have you checked for a floating neutral? Look for voltage between neutral and ground at the plug.

Bren R.

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#155576 - 01/11/07 09:48 PM Re: Who can solve this problem? [Re: BrenR]
michael_d Offline
connoisseur

Registered: 07/23/04
Posts: 3904
Loc: Up yonder
Well actually, the neutral is bonded to ground at the meter base, not the panel.

Randy, the neutral is a current carrying conductor, not a ground. The ground wire is the one and only ground although is is sometimes mistakenly called a ground.

The reason I asked if the light circuit and HT circuit shared the neutral is because that's a common practice. Even if you have a separate breaker for both, that don't mean anything unless they are both GFCI breakers and wired to code as the neutral wire goes directly to the breaker and not the panel bonding strip.

Many electricians and builders run 12/3 romex for reasons of saving labor and material. It has three conductors and one ground (Black, Red, White, ground). This saves time because you only have to pull one run of romex back to the panel. At the most logical J-box, the electrician ties in a separate 2/12 romex for another run of devices. At this J-box, the neutrals are tied together and ran back to the panel as "shared".
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#155577 - 01/11/07 10:11 PM Re: Who can solve this problem? [Re: michael_d]
SirQuack Offline
shareholder in the making

Registered: 01/29/04
Posts: 13337
Loc: Iowa
Ok, please keep in mind that I'm not an electrician, and my terminology is just information I'm confusing between you guys and my friend at work that I totally trust.

Anyway, I wired my basement myself. I have 12-2 for everything. My HT equipment is on a seperate 20amp breaker with 12-2 wire run from the breaker box on one end of my basement to the HT area. Everything else in the basement, lights-outlets, etc....are on their own 15amp circuit.

From what I'm told, and I'm sure everyone has different terminolgy, the black wire is the "hot", the white wire is sometimes called the primary groud, and the bare wire is the secondary ground. The primary ground has the prong, lug, fin, pin, or whatever the terminology is, which is wider, so the plug only fits in one way. Back in the day both of they were the same size, and many plugs did not have the "third" secondary (bare) wire.

I was told I could unhook the secondary, bare wire, from the outlet my AV equipment is hooked to, and see if the "static", not hum goes away. This would tell me if I'm getting interference somewhere else in the line, which is being picked up by the secondary ground (bare wire).

Anyway, my friend from work I talked to is 60, and has been around networking and phone topologys his whole life. He gave me information to help me wire my basement, as it was not rocket science. I'm sure I'm not phraseing everything as it might be stated in the textbooks, so sorry.
_________________________
M80s-VP180-QS8s-EP600-2xEP350 Denon3808 Outlaw7700
M22-OWM22-VP100-Denon2805
Audio Nirvana

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#155578 - 01/12/07 02:38 AM Re: Who can solve this problem? [Re: SirQuack]
BrenR Offline
connoisseur

Registered: 12/10/03
Posts: 3602
Loc: Winnipeg MB Canada
Quote:

I was told I could unhook the secondary, bare wire, from the outlet my AV equipment is hooked to, and see if the "static", not hum goes away. This would tell me if I'm getting interference somewhere else in the line, which is being picked up by the secondary ground (bare wire).


As MDrew said, the ground is a safety ground. It creates a pure path back to earth for safety reasons. You ground the boxes so if a loose hot wire hits the box, instead of it becoming energized, it trips the breaker. It's a safety issue.

Quote:

Anyway, my friend from work I talked to is 60, and has been around networking and phone topologys his whole life. He gave me information to help me wire my basement, as it was not rocket science. I'm sure I'm not phraseing everything as it might be stated in the textbooks, so sorry.


I don't think we're picking on you for nonclemature, but for mistaken reasoning. The neutral and ground wires are there for different tasks. If you keep considering your next move with a flaw in the logic, you may end up hurt.

Bren R.

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#155579 - 01/12/07 02:51 AM Re: Who can solve this problem? [Re: michael_d]
BrenR Offline
connoisseur

Registered: 12/10/03
Posts: 3602
Loc: Winnipeg MB Canada
Quote:

Well actually, the neutral is bonded to ground at the meter base, not the panel.


This (second picture under Identifying The Parts) is what I usually see. I know there seem to be a lot of differences in different places as to grounding. Some places you can still use a ground rod, I understand.

Quote:

Many electricians and builders run 12/3 romex for reasons of saving labor and material. It has three conductors and one ground (Black, Red, White, ground). This saves time because you only have to pull one run of romex back to the panel.

At the most logical J-box, the electrician ties in a separate 2/12 romex for another run of devices. At this J-box, the neutrals are tied together and ran back to the panel as "shared".


Which raises another concern that never really ever gets many eyebrows raised. Not only can you overload a hot leg of a mains circuit, it is possible to overload a neutral leg. My garage for instance, picked up the two 15A circuits onto 14-3 as they came out of the concrete pad. Now each hot conductor is carrying up to a 15A load, and the shared neutral can see 30... on a 14ga. wire. Bad.

But the NEC and CEC always seem to contradict themselves. The 12-3 solution would work better, since the extra wire size would make carrying the load easier. Then I get my wrist slapped by my electrician neighbour who mentions the CEC requires any run to the panel made with 12ga has to be connected through a 20A breaker.

Argh. The more you know, the less you know.

Bren R.

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#155580 - 01/12/07 11:09 AM Re: Who can solve this problem? [Re: BrenR]
michael_d Offline
connoisseur

Registered: 07/23/04
Posts: 3904
Loc: Up yonder
Randy,
I didn’t mean to pick on you. Yes, in years past the neutral conductor was referred to as a ground, and also the “common” conductor. As Bren stated, it is there for safety reasons. When I was an apprentice back in the early 90’s, my mentor(s) and the journeymen that drug me around construction sights were very adamant about nomenclature and the neutral was never, never called a ground. That was beat into me, so I naturally try to make that point clear. It would sound as if your friend is old school. Nothing wrong with that and I’m sure he could teach us all a thing or two. It’s just a different world now. Safety is # 1 in the electrical trade nowadays.

Getting back to your problem, I’m clueless to why the lighting circuit would be affecting your HT circuit. I had thought there may be some stray voltage or inductence on the neutral leg from the lighting circuit if they shared the same neutral. You said they don’t, so if this hum is being caused by stray voltage or inductance, it would have to be transmitted from the neutral buss in your panel. I just can’t see this happening. It may just be coincidence that the hum went away when you turned the light off. Can you check this again and confirm that it is a repeatable symptom? If it is, I’ll go to the second floor wehn I get back to the office and talk to an EE/PE I know. He’s nothing short of brilliant and if there is a correlation, he’ll know what it is. This fella is one of the few engineers that came from the trade and then got his degree. RE: an engineer with common sense - a rarity.

Bren,
When they say “main panel”; they are referring to the service panel from the power provider (meter base/service panel/line disconnect). And yes, ground rods are still used, and also required for residential applications. Depending on the service / load, the rod can be different sizes and driven to different depths. You also tie the ground rod to the water main coming into the home/facility and the meter base/panel. In industrial applications, this varies. Many plants have a grounding ‘grid’ for lightning protection. You tie the facility into this grid, but again, it’s at the service panel/disconnect to the load side facility.
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#155581 - 01/12/07 11:36 AM Re: Who can solve this problem? [Re: SirQuack]
jakewash Offline
shareholder in the making

Registered: 12/26/03
Posts: 10398
Loc: Calgary, Alberta
Have you tried turning off each breaker for the house and rechecking for the static? This would enable you to find the culprit circuit, if its a circuit at all.

Could it be one of your new components has an issue, the Emotiva or monoblocks has a bad internal circuit? Have you tried using just one monoblock then the other to see if only one will cause the static but 2 definately does, obviously. I am thinking the Emotiva has a bad ground or just a bad connection on its boards.

The static wasn't there with your old amps right?
_________________________
Jason
-----------------
TTTHHHPPPPPTTTT!

My HT

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#155582 - 01/12/07 12:06 PM Re: Who can solve this problem? [Re: michael_d]
dllewel Offline
connoisseur

Registered: 06/20/05
Posts: 1189
Loc: Utah, USA
Randy, same here- no harm was meant in nitpicking the terminology- just trying to be clear. I agree, you are getting good advice from your co-worker.

Quote:

MDrew said... I had thought there may be some stray voltage or inductence on the neutral leg from the lighting circuit if they shared the same neutral. You said they don’t



I am still unclear if this is true- because of the confusion we may have had in the terminology. I know that you didn't believe it was the lighting circuit because you turned off that breaker and still had the noise, but I would guess that the white wires from both the 20A HT circuit and the 15A light circuit are indeed connected back to the same Neutral bus, and therefore shared. They should be really.

I would agree with you and your co-worker, try the ground isolation first (use a cheater plug so you don't have to physically disconnect the ground). If that solves the issue however, investigate further into the cause as removing the ground should not be a permanent solution.

Good luck Randy, we hope you get it solved and just want to be of help.

Dave.
_________________________
-Dave

M80s VP150 QS8s EP500s
ravenmanor.com/cinema/

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#155583 - 01/12/07 02:31 PM Re: Who can solve this problem? [Re: dllewel]
SirQuack Offline
shareholder in the making

Registered: 01/29/04
Posts: 13337
Loc: Iowa
Thanks guys for the input. One thing I want to make clear is that I'm trying to remove the "static" sound I'm hearing, not a "hum" sound.

Here are my two situations:

1) Hum - I'm still hearing a just a "little" bit of hum sound from my 80's, but it is hardly noticable unless you get real close to the woofers, etc.. I've heard that a very efficient speaker can produce this sound if your amp has a bit of hum from the transformers. If I place my ear over the top vents of my MPS-1 monoblocks, I can hear a little hum, so I'm guessing it is transferring through the speaker wires to the 80's?

Now, the hum used to be worse when I first hooked everything up. I also heard some "hum" in my vp150 center, which is not going through the amp. Thanks to "Wid", he helped me troubleshoot the issue. My ep600 was sending a hum back through the "Blue Jeans" coax, through my Denon, and to the center speaker. I removed the ground screw on the back of the ep600 and the sound went away totally in the vp150, and greatly reduced the hum in the 80's.

2) Static - I hear some static like sound in the tweeters of my 80's. It sounds almost like when you have a walkie talkie volume turned way down as low as possible. sssssssssshhhhhhhhhhhhhhhhhhhh with a little bit of staticy ticking like sounds mixed in. At first I was lost as this seemed to come and go. As I said before, I figured out that it would go away when I turned on my closet light, which again is on a seperate circuit. Then I turned the breaker on that circuit off, and still hear the noise.

As jakewash mentioned, and my buddy hear at work, I could try one-at-a time turning other breakers off to see when the static goes away. It just is funny that when I turne the closet light on, it goes away. It is almost like by turning on the closet light, it is absorbing the static before it gets to the amp.

Thanks so far for the help.
_________________________
M80s-VP180-QS8s-EP600-2xEP350 Denon3808 Outlaw7700
M22-OWM22-VP100-Denon2805
Audio Nirvana

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