2. tech-talk
  3. 1094874272

I want surge protection, but I have no grounds

Hello all, this is my first post.

I am seeking advice on how I should handle a problem with my apartment. I recently upgraded my CD player and have suddenly become concerned about surge protection. Unfortunately, I can't use a surge protector effectively because I have no grounds in my apartment - only 2-prongers.

I read that I could use the grounded adapter plugs to solve this problem. After installing one, my multimeter reads 123V between the hot and neutral, and only 35V between the hot and ground... I believe this means the boxes and conduit are not metal and cannot serve as a ground. I tried again on 3 other outlets with the same results on every attempt.

At this point, the only options I can think of are:

1) Don't worry about it. Surge protection is overrated? One thing I can say is that about a year ago lightning struck a transformer outside the apartments and blew the video card and modem on my computer (no stereo damage fortunately).

2) Rig something up. I heard this was not very smart, but I could run a wire from the ground on the adapter to the drain on my kitchen sink. Hopefully that would give me a solid ground connection, and wouldn't electrocute me in the shower one day.

3) Buy a ground electrode and put it outside my window. Unfortunately, I don't even know what these look like, how much they cost, how hard they are to install, or if the owner would freak out if they found it (I live on second floor).

4) Suggestions? Is there a product or option I haven't heard about? My budget is limited... but spending a little now is better than replacing my entire system later.

Thanks for any help offered,
Will
wtwood
10 responses Add your response
wtwood OP
4 posts
 
I didn't realize that surges could be through the neutral, and I now see that it does not protect against them. Unfortunate. Do these occur with the same severity and frequency as hot line surges?

Regarding the supply impedance issue: I live in an apartment and rarely play the system at high levels. My receiver is rated 35Wx2. Does my modestly powered system make this less of a problem than if I had a big 5 channel system for instance? Does current have any relationship with impedance in this situation? Intuitively, I don't see why it would, but I don't really understand how the unit functions and if it behaves differently at different currents.
nealhood
199 posts
 
MOV based surge arrestors don't merely divert current to the ground and neutral conductors (circuits). They dissipate the energy of the surge pulse in the MOV assemblies. Now the ground or neutral conductors do carry current during these surges but, this should cause no concern assuming your house wiring is in accordance with the safety standards and codes designated by the NFPA. These shunt type MOV units often include a one or two stage RFI filter as standard also. And, they offer minimum series impedance, certainly an advantage when feeding a power amplifier.

Nevertheless, the brick wall filters are good also. But, I do question their ability to properly clamp a surge voltage on the hot conductor if no current flows into the gound. Normally surge pulses appear between hot and ground or, neutral and ground. If these units do not pass current to on the ground conductor then how do they limit the peak voltage appearing on the hot conductor during a hot to ground surge(especially slow rising surge)? Remember an inductor does not offer much impedance to a slow rising waveform - such as when your utility power merely fluctuates due to system instability/oscillations, etc. when the grid is subjected to disturbances such as blowing a throwout on the pole. Also, these inductor type filters generally exhibit a significant series impedance which may hinder the stiffness of a power amplifier. But this should not really be a major concern because supply impedance is often overplayed in the audio hyped marketplace.
tbg
5,263 posts
 
Have you read a review? All it seems to be doing is surge protection and some filtering. It may be that your present sound is better.
wtwood OP
4 posts
 
Confirmed this morning... the product listed below functions fine without a grounded outlet. It also has built in filter.

http://www.pricewheeler.com/prod8r.htm
wtwood OP
4 posts
 
Well, after spending my entire weekend doing online research and rigging a ground wire to my plumbing, I think I may have come across a real solution to my problem. This company called "Brickwall" manufactures surge protection that does not divert power to the ground wire... unlike what appears to be 99.99% of other manufacturers.

http://brickwall.com/grndcur.htm#form

According to their website, "Almost all manufacturers of shunt mode surge protectors (those utilizing MOV’s) design their products to divert surge current equally between the ground and neutral wires. A surge protector should not divert surge current to the ground wire....

...Brick Wall surge protector products are based on the current (hence voltage) limiting of a massive inductor. Residual energy that leaks through is captured by a series of electrolytic capacitors. There it is slowly leaked back to the neutral at a harmless level. Outside of trivial amounts of parasitic capacitance our Series Mode surge protectors do not put any surge current on the ground of your systems."

I get the gist of what they are saying, but since I'm not an EE I think I will call the and check out the details. Hopefully, this will solve my problem and also offer a good unit to use in the future even if I move into a place that has decent wiring.
tbg
5,263 posts
 
I strongly suggest you get an electrician. If you got 120V does that mean between the hot and ground the new ground? Is this a very old apartment? It does not sound like it if the outlet box is plastic. If there is a ground wire to the box, you should be grounded if the duplex is new, but if the ground wire is either not there or not connected to the duplex, you have no ground. Mankind lived for a very long time without grounds with the population increasing greatly; so I would not be too worried, but I still strongly suggest you get an electrician if you want to make changes.
wtwood OP
4 posts
 
I tried it several ways. With the screw out, directly to the adapter's exposed metal ground connector, and to the adapter's 3rd prong. I really can't explain why I got 35V instead of 0, but after taking the cover plate off the outlet, it looks like a grey plastic box.

I wired up the ground to the kitchen plumbing drain temporarily yesterday just to see what happened, and I got a 120V reading.
nrchy's avatar
nrchy
2,124 posts
 
Or do you mean you have no grounds for wanting surge protection?
alexanderj
139 posts
 
Will:

Was the 35V hot to ground reading via a painted screw? If so check to see if you get a higher reading to some unpainted threads. A lot of older apartments were wired using conduit systems where the conduit "should" make a good ground. I suspect Rockvirgo's fudge job involved common wiring the ground pin to a neutral wire. Potentially hazardous, against the National Electric Code, and not recommended. Especially dangerous if the circuit is part of a "common neutral" confirguration where the neutral is shared between 2 circuits.
rockvirgo
587 posts
 
When I was in the same boat a clever electrician wired up the old house with some three prong outlets with one hot and two commons. Can't say exactly how he did it, but he made a jumper for each outlet out of single wires he pulled from a coil of three conductor Romex. He charged about $100 to do 6-8 outlets for one hour's time plus the cost of the outlets.

My primary concern was the owner's manuals for my three pronged equipment that stressed "under no circumstances defeat this ground." The electrician explained that the electric company provided the ground back at the power plant so it was better than nothing. His fix did make the ground lamp on the surge strip illuminate so at least the strip seemed happy. The main trick with this fudge job is making sure the hot polarity gets connected the same way in all the outlets. When it's reversed the ground lamp on the strip won't light. Luckily I discovered a reversal or two while the electrician was still on site so he fixed the ones that got flipped. At the time I didn't have a nifty handheld outlet tester so I can't say what it might have shown.
Log in to respond
More to discover
80x80
B&W (Bowers & Wilkins) 801D4
80x80
RSX MUSIC SERVER RSX MUSIC SERVER
80x80
RSX MUSIC SERVER RSX MUSIC SERVER