Can I ground it myself?

September 1, 2005 3:45 PM

Is there a safe, easy way to ground a household outlet?

I live in an older house with ungrounded outlets. Normally this is not a big problem. It does make plugging a guitar amplifyer into the wall a mess, since the lack of ground contributes an incredible amount of hum. Is there an easy way to get this fixed for at least that one outlet? Should I just bite the bullet and call an electrician?

posted by Gilbert to home & garden (11 answers total)

You can use one of the adapters that allows you to plug in grounded appliances to two-pronged outlets, but attach a screw to the grounding pin on the adapter and run it to part of your water piping.
posted by odinsdream at 3:55 PM on September 1, 2005

You could try connecting the ground lead to a metal drain pipe. This will only work if the house doesn't have PVC drains and the pipes go underground. It still may not be a great ground, but it might be good enough.

I would never recommend this as a general purpose solution to grounding an outlet. If you were to e.g. plug something in that had a metal chassis connected to the ground wire in the plug, then in the case of a short to the chassis you could potentially be betting your life on the drain pipe not having corroded too much to conduct. In other words, yes you should have an electrician do this kind of thing in most cases. But if it's just for the one specific purpose of grounding your amp and nothing else, then the drain pipe method is probably fine.
posted by Rhomboid at 4:01 PM on September 1, 2005

Install a GFCI in that outlet. Check your electrical code. In many areas GFCIs are coded for 100% safe replacements to provide ground protection on circuits where ground is not available. I'm not sure about elsewhere, but I am certain that in Canada this is allowed.

GFCIs will cost about $5 - $10 per outlet ($10 - $20 per box).

(For those wondering, GFCIs measure the amount of current being drawn from hot and returned to neutral. If the amount differs by more than 2-3 mA they will trip. The difference would be power shorted to ground, and since the outlet trips, it's rendered safe in the case of an electrical short / shock.)

(Most modern houses will have GFCIs on all outlets in the bathroom, you'll often find a red test and black reset switch on them.)
posted by shepd at 4:06 PM on September 1, 2005

You could run a copper wire to a copper cold water pipe. You will want to polish up the spot where you connect the two for the best connection.
posted by Pollomacho at 4:42 PM on September 1, 2005

FWIW, grounding may not solve your problems with the guitar amp. Invest in a Furman power conditioner and thank me when you're a star.
posted by realcountrymusic at 5:22 PM on September 1, 2005

shepd I was under the impression that GFCI only prevented a short from happening. Is that the same thing as grounding for buzzy noise purposes? It does sounds better than running wire around the room.
posted by Gilbert at 6:50 PM on September 1, 2005

if the home is older it may have metal conduit that is grounded at the fusebox. All it takes to ground the outlet is a new outlet-which will have a ground terminal (about $2), and a pig tail (short piece of 10GA wire). Kill the breaker to the outlet and unscrew the plate. Use a flashlight and see if the box is metal. If so, get a drill and drill a small hole in the back of the box. Connect the pig tail to the new outlet on the green (or ground) terminal and then connect the other end of the pig tail to the box using a screw in the hole you just drilled. For about another $6 you can get an outlet tester to verify you've done your job well. All of the supplies can be purchased at Lowe's or Home Depot.

I remodeled my 1950's era home and replaced all of the two prong un-grounded outlets in this manner (also putting a single GFCI outlet on each separate circuit). An easy and efficient way to protect equipment and people.

However, if you are only worried about the EMI I agree with realcountrymusic.
posted by HyperBlue at 7:54 PM on September 1, 2005

There are any number of power conditioners which break the ground plane. One of these will fit the bill. [I don't know the Furman, but given the mention above it probably does.] Any of these should work fine to cut the buzz. Head to the local music store or hifi store and ask. If they don't know, go to the next one. These things are not cheap by the way. Expect to pay several hundred dollars. In addition to cutting the buzz they will give you a cleaner sound.
posted by caddis at 8:29 PM on September 1, 2005

You're not safe playing a guitar amp through an ungrounded outlet, by the way. Ungrounded amps can build up quite a wad of capacitance. They also connect the strings of your guitar (and the bridge and tuning machines) directly to ground, or what the designer intended be the ground connection. Since most players are touching the strings at least occasionally, this means that YOU may be the shortest path to ground.

People die this way all the time, often from a shock running across their heart, from their fingers to their lips (which touch the casing of a properly grounded mic).

So, do ground the outlet.
posted by ikkyu2 at 8:17 AM on September 2, 2005

Gilbert, it probably won't solve the buzzing, but it is a general way to keep the outlet reasonably safe without a ground. If it works for you, then great. Otherwise go with the grounding to a COPPER or GALVANIZED (or lead, if your house is incredibly unhealthy :^) ) cold water pipe suggestion. Just remember to use decently thick gauge wire and a wire to pipe clamp. Don't just tie or electrical tape it on and expect results. :^)
posted by shepd at 1:48 AM on September 3, 2005

shepd I was under the impression that GFCI only prevented a short from happening.

As mentioned before, a Ground Fault Circuit Interrupter measures the current difference between hot and neutral--a substantial difference means that the current is going to ground instead. This is bad because if current is going to ground, it often means that it's going through you. And that's not real great.

That's why the ground is there, by the way. If there is a wiring fault, the current goes to ground through the ground connection in the wall and your water pipe or ground electrode, and not through your body. Without the safety of having a real ground, you need that GFCI there to cut out the circuit if there is a ground fault (meaning, you're probably getting shocked).
posted by RikiTikiTavi at 9:25 PM on September 3, 2005