This is a power cable being used for my subwoofer. I have a ground loop currently. According to the manufacturer of my subwoofer, due to it's design, it is perfectly safe to remove the ground. Right now I do so with a cheater plug but I would like to avoid having to use it. The power cable in question is Oyaide Black Mamba V2
How easy is it to take a power cable apart and disconnect the ground? Is it best to do so at the IEC side or the pronged side? What is the process for doing this?
So you guys think its fair to nitpick me to death, then remove my post so people don’t get the explanation.
No one here has nitpicked - they've corrected your profound errors, that you then punctuate with proclamations such as:
That's how I defend my position. By being right. Works every time.
It seems to me that others here have been more respectful of you that you have of them. Your post could only have been removed by moderators so if you're unhappy that it was deleted, your ire should be directed to them.
The reason, as I recall, for neutral and ground being separated has to do with Ohms law.
Neutral is a working conductor in the sense that it SHOULD normally carry 100% of the current the hot does. So, 15-20 amps in a typical residential application.
Due to many factors, the impedance of neutral can become significantly non-zero.
15 A * 0 Ohms = 0V
15 A * 5 Ohm = 75 V
etc. etc.
So it is quite possible, if not probable that neutral can be non zero. Now imagine if that the ground wire no longer exists (as in old homes/appliances), but the chassis of your equipment is bonded to neutral (old washer/dryers). See the problem? You now have gear which can develop a significant shock factor by touching it. Happened to me with an old dryer once. :)
The entire point of a safety ground in appliances is to have any voltage which accidentally touches the chassis to drain to ground and hopefully blow a fuse or breaker.
Of course, faults can happen in the ground conductor as well, but operationally, if the ground develops a high impedance, it’s not going to normally develop a voltage because current = 0.
This part is kind of important:
Because each panel can introduce a new impedance problem, the neutral and ground must remain unbonded except at the service panel. The service panel is the first one after the meter. So, if you add subpanels, you run 4 conductors. +120, -120, Neutral and Ground. One trick here is that the ground may form a loop. You don’t necessarily have to pull the ground from the panel....but that leaves open the possibility of a future contractor not knowing this, so don’t.
It may help everyone to think about two separate advancements that have occurred in home wiring. I’m rusty on the full history, but if you’ve done any upgrades you may have felt like an archeologist, and learned about a few things.
1 - The invention of the polarized plug. When this happened some makers, like lamp makers did in fact use this as a ground. So long as the impedance is near zero, no problem.... but if that lifted for any reason like a loose wire, corrosion etc. voltage at the lamp could happen.
2 - The separate ground conductor which evolved over a few iterations, not sure exactly the timing but:
Originally no ground wire needed when metal conduit was used. This is no longer acceptable. Conduit not considered reliable.
Originally you could wrap a conductor around any old place to ground outlet boxes. Now must use special fine thread green screws and tabs.
The addition of the appliance safety.
The point to #2 here is that much has evolved from the early 2 wire system to today’s 3 wire. It didn’t happen until there was a need. Each of these advancements was made because the previous state of affairs cost too many lives and homes.
Edison didn’t come up with these ideas. They were created out of necessity.
Today gear with a metal exterior must be grounded OR be double insulated. This is why my plastic body blender has no ground, but my stainless coffee pot does. I think there may be some exception for gear with outboard, low voltage supplies (i.e. wall warts) too.
Edison was a proponent of DC, he intended to wire our homes like giant flashlights. Tesla was the man behind alternating current. There was a need for grounded appliances, etc, from day one, Erik. No different really than seat belts. Just took a while to evolve.
First off Nemesis. After a talk with a "Sales rep"? You are going to "possibly", cure a hum problem by removing the ground pin from a piece of gear? And this was deduced by the, "Sales Rep" using this, "information", which you provided about this, "Ground loop" right? That info came from where and was offered in what context and by whom? Seriously, Doesn't the above kind of sound like a classic case of, "The blind leading the blind"? With both parties about to walk happily off the precipice of a very tall cliff and into oblivion. Would you have a "Frontal Lobotomy" procedure done after being diagnosed by your "Bank Teller"? There are other ways to fix your "Hum". Many are listed above. "It sounds to me like your subwoofer itself may be the issue". Just please , don't take anymore "Electrical" advice from someone whom you do not know and have never met. And please, don't burn your home down or worse by following it.....
"Miller Carbon"? This quote; "You've got millivolts of voltage potential on that neutral wire, we can eliminate that infinitesimally micro risk that hasn't caused a single death in a million man-years." And we said, "I don't have the foggiest what "potential" means but "voltage" sounds scary so yeah sure go for it."
That is the most moronic statement I have seen here on Audiogon. When you talk about other subjects which you know nothing about it really is not a big deal. But when you give advice which could really hurt someone? Especially when you also then argue your little, "point", after several have pointed out this fact? That isn't just ignorance. It is wrong. So quit.
Other than the "FACT", that a " neutral", or "bonded conductor", not only "Can" kill but HAS and indeed DOES kill people all the time? Plus the fact that you do not have any understanding of "Electrical potential"? And also seem not able to "Take the hint", when people are trying to be nice. Other than that. I am sure you are a "Hell of a guy". "Or Gal"..... By the way, this is from me, someone whom went to the trouble to become a,"Licensed" electrician.
While it's not likely to get a shock from a sub, if it was grounded, I would try and keep it that way. The ground loop is most likely from cable TV. Unscrew it and see. Find a way to break the ground there. Jensen Transformers is a good solution.https://www.jensen-transformers.com/home-theater/video/
Yikes if you insist on the removal of the ground pin at least install a GFCI receptacle in the place of the standard outlet. In the event your sub has an issue it will trip before any damage to person or property. Some of you do not have the understanding of how an electrical system functions. Stick with what you know. It is dangerous to advise on thing that can cause damage to people and/or property. Remember true intelligence is knowing when not to advise.
Yikes if you insist on the removal of the ground pin at least install a GFCI receptacle in the place of the standard outlet. In the event your sub has an issue it will trip before any damage to person or property.
"According to a 1999 study by the American Society of Home Inspectors, 21% of GFCI circuit breakers and 19% of GFCI receptacles inspected didn’t provide protection, leaving the energized circuit unprotected. In most cases, damage to the internal transient voltage surge protectors (metal-oxide varistors) that protect the GFCI sensing circuit were responsible for the failures of the protection devices. In areas of high lightning activity, such as southwest Florida, the failure rate for GFCI circuit breakers and receptacles was over 50%!" See https://www.ecmweb.com/basics/article/20901772/how-gfcis-work
A GFCI will only help if the CBLF is grounded and not contacting the neutral. A GFCI will not trip if the CBLF is between Hot and Neutral.
If you have GFCI, test them monthly and after any electrical event, preferably with an external tester.
UL943 governs GFCI in the US, with Mexico/Canada having similar specs, and I believe EN specs are similar.
- 2003 update to improve surge suppression to protect components. - 2006 updated to detect some miswiring - 2015 added automated testing and a whole host of required fault detection w.r.t. the proper operation of the circuit. Newer GFCI should be much safer than old ones w.r.t. guaranteed operation. Self check is once every 90 minutes.
GFCI outlets have more stringent requirements on what happens when a fault it detected compared to GFCI breakers, but most new breakers on the market appear to be adapted the more rigid requirement to disconnect power, not just indicate a failure.
Was looking at some of the controller chips and they will even detect ground/neutral faults, and will check for failures more often.
I had a similar issue and I just removed the ground wire from the ground prong. (I checked with the cable manufacturer first before I proceeded.) No issues and no sound degradation from using a cheater plug. Simply remove the screws from the plug and then push aside the ground wire from the prong and make sure that is doesn't touch anything else.
Plug it in and unplug it about a thousand times, this has worked without exception on every Skilsaw and extension cord I've ever owned. (couldn't resist any longer)
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