# Question about my wall outlets that have no ground



## Fiveway (Mar 21, 2010)

Is that going to cause problems with my amps and/or audio in general? I've noticed that both amp and my desktop monitors hum pretty badly in this house.

Anyone know anything about this stuff and possible fixes, other than rewiring the house?


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## bw66 (Dec 17, 2009)

You used to be able to get "cheater plugs" that could plug into a two-prong outlet and they had a metal tab that you could connect to a proper ground. I can't imagine that they are still legal, but you could try. You could probably just re-wire a few outlets where you need them rather than the whole house.


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## keeperofthegood (Apr 30, 2008)

There are two possibilities with two wire houses: 



 there is a ground VIA metal conduit or armored cable use and in this case, the center screw of the front of the outlet should connect to a metal plane inside the outlet that is then connected to the shell of the outlet box inside the wall, here is where the three-to-two wire converters would be usable and safe..
 There is no ground at all due to there being no other metal connection to the outlet box than the wires.










How it is depends on when the electrical was done because as the Electrical Safety code changed so did how "new" wiring change.

Now, this is where people (homeowners the DIY kind) get themselves into trouble... "new". House and other electrical is grandfathered. Once done to the code of the day, it can stay like that till the cows come home. HOWEVER IF YOU CHANGE any part of your home electrical system the ENTIRE home then has to be brought to CURRENT code. Lots of people do not think of this, or do this. So, if you think "I will just have a new three wire run to this room here" nope, you do that you have changed your homes electrical and so the whole home has to be brought to code (when I was learning this, some people would go so far as to include changing a broken switch but it isn't generally viewed that anally however the code is written to include that). When this will be "known" is when you either try to sell your home and a new owner has an electrical inspection done (for prospective purchasers only makes sense) OR if you have a fire and the insurance company looks for every possible reason to NOT PAY YOU and things like messed with electrical they will HAPPILY use against you.

As to which you have, one or two, only way to really know is to have a qualified licensed electrical inspection done on your home. Even having a shielded system does not mean you have continuity to earth or that it isn't itself hot due to a short or other damage elsewhere. However, in ALL honesty, you are farther ahead to talk to your bank and plan a home renovation and up-do the wiring to current standards. If it was me, that is what I would do. Those old wires, the metal may be somewhat good but the insulation was tar and paper, even my home that was built in 1969 that I grew up in, the three wire used in that was tar and paper mixed with a plastic on the wire itself. When we reno'd in the 1980's that paper and plastic was so very dry and brittle we ended up redoing a lot of the house wire.


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## Fader (Mar 10, 2009)

Keeps. Can you please tell me what rule in the electrical code book that states you have to do a complete rewire if you want to upgrade one circuit?
Just curious.

Fiveway. What year was your house built? Hum is caused by electromagnetic fields. If you have knob and tube wiring, you can have elevated magnetic fields over a fairly broad area of your dwelling. They are generally of a low magnitude.

Transformers cause very intense EMF but it drops off rapidly as you move away from the source. You can also get elevated fields from utility power wiring and pole-pigs. Are you on and outside wall where the building supply conductors run down the side of the building to the meter? Try moving your gear to the other side of the room and see if it helps.

You can check for EMF with a gaussmeter. Anything under 2 or 3 milligauss should not cause hum.


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## keeperofthegood (Apr 30, 2008)

Oh man it has been literally YEARS since I got my first 1000 hrs of my apprenticeship and just as many since I sat down and read it cover to cover (I was a lot more ambitious as a teen than I am these days...). Much of that is decrepit old brain stuffs now. Too cold, too tired, and I am terrified of heights. I went into college electronics instead. BUT, the code is written that your electrical is set to the time it was built, that modification to that means you are responsible to bring the remainder up to current code standards. That is how the code is, it is not how a lot of people treat it.


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## Fiveway (Mar 21, 2010)

Thanks for the replies. I rent this house, so there's not a ton I can do to it, other than replace the odd receptacle. The house was built in 1945 and the wiring, with the exception of the panel, looks original. The panel has been updated fairly recently it seems. Not knob and tube, but old cloth covered 2wire. 

So could I be getting interference from all the wall warts for my pedals. They're all plugged into a power bar right beside my amp and directly below my computer. I checked again and the hum is really noticeable through my studio monitors. As in there's no way I'm recording anything.


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