Ask MetaFilter questions tagged with grounding

Couple of car troubleshooting questions anyone?

dance — Sun, 08 Jun 2008 11:27:35 -0800

Snazzy Blaupunkt stereo installed in car, but I find myself plagued by a whine which I am assuming is originating at the alternator. If anyone could explain in simple terms how I might be able to eliminate this noise without too much fuss I would be really grateful! I realise it's almost always a grounding issue or speaker/power cables getting tangled together - but I haven't a clue how to go about re-grounding the stereo when it's so tight and dark behind the dash. Strangely the last stereo had no such problems, was also Blaupunkt and the new stereo was able to use the same connectors. Ignoring the fact the stereo itself is changed, the back of the stereo still looks a lot like this.

Plus! Huge bonus points if someone could suggest why my front left wheel sounds wobbly when driving on unmetalled roads even though the roll bars have just been changed....

Help me kill the hum

Artifice_Eternity — Tue, 15 Jan 2008 19:31:39 -0800

MusicGearFilter: I've got a hum in my recording/performance setup. I think I know how it's getting in -- a balanced mic cable going into a piece of gear with an unbalanced jack. How do I fix it? Full details within. My headset mic has a permanently attached cable with a XLR plug on the other end. I connect this to an extension cable, which has an XLR jack on one end and a TRS plug on the other. So far, it's a balanced signal.

The next step is where I think the problem occurs: I'm plugging that TRS plug into my Zoom G2 guitar effects unit, which has a 1/4" (mono) input jack. Then I send the signal out to my mixer.

I only get the hum when I have the G2 in the loop. When I plug either the mic's XLR plug or the TRS plug from the mic extension cable directly into my mixer, the hum disappears.

The hum also disappears if I touch any conductive part of the signal chain -- the mic cable connectors, the G2, the G2-to-mixer cable connectors, or the mixer itself. Apparently I am grounding everything with my body.

As far as killing the hum at its source, I've tried that. A lamp dimmer was the worst offender, but I'm still having some problems with the power adaptors for my music gear and some of my computer peripherals.

Any suggestions on how could I fix this? Is there something I could insert somewhere along the chain to ground everything? This is my first experience dealing with this kind of issue, and my Googling hasn't produced any useful answers so far. The ideal solution will be workable both at home and when I play out.

Lighting arrestor to dampen the ground voltage differential

jumpsuit_boy — Wed, 26 Dec 2007 18:24:19 -0800

Using a lighting arrestor to dampen the ground voltage differential between two building. Ok so my mother moved down to mexico a few years ago. The place she rents does not have a phone but the neighbor does. So she got DSL at the neighbors place and then we ran a phone line over to my mothers place to hook up the DSL modem. This all works great.

Now the neighbor has bought a computer and wants internet access. So I need to get a connect back over to her house. (yes I could move the DSL modem to the neighbors but the house is poorly grounded and they burn out cordless phones all the time so I do not expect the DSL modem would fair very well. I have grounded by mother place so it is not as much on an issue for the DSL to stay are here place.

I have two plans one long term and one short term. In the long term I will place two external wireless modems down there to connect the buildings. They have to be external because all the buildings have 12 to 15 inch thick concrete and masonry walls that I wireless signal will not make it thru. Also I will have to cut down a few trees probably to get a clear shot.

Now the short term solution an the reason for this question. I am thinking I can run long outdoor grade ethernet cable between the buildings and use a lightning arrestor http://metrix.net/cat-5-lightning-arrestor-p-23.html do dissipate the ground voltage differential between that is bound to be between the two building.

Am I crazy to think that this might work?

Help keep my computer from frying.

BrotherCaine — Tue, 24 Jul 2007 21:39:28 -0800

I need to add grounding to an outlet. How bad an idea is it to chain the ground to the ground of another outlet that is on a different circuit a few feet up from that one? Basically I live in an apartment in California. The kitchen and bathroom outlets are grounded. All other outlets have open ground. No outlets have hot/neutral or hot/ground reversed. On the opposite side of the wall that my computer's UPS is plugged into is the kitchen outlet that is grounded. These outlets are on different circuits. I'm thinking about running a wire between the ground terminals on each outlet as a cheap and dirty fix which I will remove when I move out. All outlets are three prong, none GCFI. I intend to do any work with all circuits in the circuit breaker set to off, and will check for voltage in each outlet before starting. I am obviously not an electrician. There does not appear to be any metal conduit around the wires that could be used as a ground.

I found out about the problem because my UPS said I had a wiring fault, but the computer seems to work fine for now.

Also, the circuit breaker is wired oddly (from my limited perspective) in that you need to turn multiple circuits off to cut power to the bedroom outlets.

Getting rid of the phone buzz?

kamelhoecker — Thu, 12 Apr 2007 08:18:42 -0800

My phone has a loud buzzing noise. When I touch the screw on a lightswitch plate, sink faucet or a metal lamp, the buzzing stops. What is happening – and more importantly how can I use the phone without having to ground myself? My phone service is through my cable provider. The cable comes into the house, splits into a box for internet (cable "modem") and into another box for my phone service. My phone connects into my "phone box" with a standard telephone wire.

I did some research and my hum/noise problem sounds like a ground loop – except that my phone, internet modem, router, laptop, etc. are all not grounded. (They have only 2 prongs. But maybe the cable is grounded.)

Also, confusing (to me) is the fact that the problem goes away when I am grounded. What does me being grounded have to do with my phone?

Grounding appliances in a 2-prong apartment?

electric_counterpoint — Thu, 05 Jan 2006 20:35:04 -0800

Grounding my old Marantz stereo amp in a two-prong outlet? (We're talking American 110v.) Right. So. I've moved into my new, old apartment. How old is it? It's so old that I was greeted with warnings of lead-based paint. Also troubling are the rooms' uniform, two-prong outlets.

I've got an old Marantz stereo amp/receiver through which I run my digital audio (model escapes me; probably has a "3000" in it? Not extremely valuable, but still.). It features a grounding post, to which I've formerly attached a regular three-prong extension cord (with the hot and common wires taped up). Plugged into a three-prong outlet, this connects the stereo's ground to the building's own wiring, and stops the speaker buzz.

Obviously, that solution doesn't work now. I've got a few of the common type of adaptor seen below, which have a little a little metal ground tab and a sternly embossed admonition to connect this to the building's ground. More explicit instructions, I assume, were excised for reasons of space. Such considerations mean nothing here, AskMeFi, so please go to it!

Starting Tai-Chi or Yoga in Los Angeles

anonymoose — Wed, 07 Dec 2005 18:17:15 -0800

I want to learn Tai-Chi or Yoga in Los Angeles. Where's a good place to do that? (For those outside of L.A., what are good things to look for when finding a place to start Yoga or Tai Chi? How often should one go when starting out? What else should I know?) I'm in Studio City/North Hollywood, and would either like a place close to home, or a place that offers classes at a time when there's not much traffic. I'm looking to gently recover from almost a full year without significant exercise, as well as correct my posture and get some sense of grounding so that I don't wobble, shifting my weight from left leg to right leg when I try to stand still. I'm pretty attracted to Tai Chi, though Yoga seems to offer similar benefits.

Laptop Audio Hum

monsta coty scott — Thu, 16 Jun 2005 13:27:02 -0800

I use my laptop in conjunction with midi controllers as a live instrument. When running off the battery it sounds great through the PA system, but when I plug in the AC adapter I get a very loud humming sound. Is there any way to get rid of this? I usually just run the laptop off the battery and hope it lasts through band practice, but lately the battery life has been shorter and I would like to run it off AC power. Is this hum simply a grounding problem? If so, how could I go about wiring the laptop and the PA to a common ground?

How can I ground my computer and audio setup?

fuzz — Fri, 10 Sep 2004 06:53:20 -0800

My gear is giving me electric shocks, and I don't know what to do. [more inside] I've got a complicated setup with two computers and lots of external peripherals and audio equipment. Cables run in all directions, with everything connected to everything else. The only high-wattage devices I've got are a very old stereo amp and a monitor.

Every once in a while I'll get a small shock from touching something. I've had it happen with a DVD burner, one of the PCs, and an electric guitar (which is plugged through some electronic gear into a PC, not into a guitar amp). It's been going on for about a month.

I haven't gotten fried yet, and neither has my equipment. Should I be really worried? I'm completely ignorant about electricity, so can anyone give me an idea about what might be wrong, and recommend things I can do to troubleshoot this?

Installing window air conditioners

stupidsexyFlanders — Sun, 16 May 2004 09:20:47 -0800

I have an old house with old wiring in the walls. The question inside is about installing window air conditioners. Old wiring doesn't necessarily= dangerous, in fact I have had an electrician go over the house thoroughly, upgraded the service coming in to modern levels, replaced the main box etc. Problem is, the bedrooms have no grounded outlets, and I want to put window air conditioners (with 3-prong, grounded plugs) in those rooms. Ordinarily I would just use an adaptor, but the owner's manuals seem to really freak out about this, seems like more than just the usual liability CYA type of warning language. What exactly is the risk if I use an adaptor, and are there any safe alternatives to ripping out walls and replacing the wiring within? These are small 5000 BTU airconditioners going in bedrooms on the second floor with no easy access to the basement (where plenty of new, grounded outlets exist).

How to properly ground computer equipment when I only have 2-prong outlets?

theNonsuch — Mon, 05 Jan 2004 20:10:53 -0800

Is there any way to properly ground computer equipment when there isn't a ground available from the plug? (more) I live in a very old apartment, with very old wiring. Many of my electrical plugs are three-prong, but a visit from a electrician confirms that none of the plugs are actually grounded.

Is there anything I can purchase (APC unit, etc.), or anything I can do to properly ground things? I obviously cannot get my landlord to replace the wiring, as that would entail replacing the entire electrical structure of the apartment (35 units).