an argument against ground probes...............

[organicreefer]

i came across this article,and im not an ee or anything ,but its sounds extremely logical to me .give it a read and tell me what you think:http://avdil.gtri.gatech.edu/RCM/RCM...ingProbes.html

anyone want to buy a few slightly used ground probes?;)

[ReefHog]

Interesting,

I'm not an electrican but I do quite a bit of electrical work at my job replacing recipticals, Switches, ballasts, heating elements, etc. Now I work on live"hot" wires all the time. Yes your suppose to cut off power before you work on such items but many times I don't as I don't feel it's necessary if your not grounded. I can hold a 110 volt wite in my hand with no problem as long as no part of my body is touching ground. If I were to touch ground ( which has happened more than once) I get a shock.

This is why I never understood the grounding probe thing. Isn't it the same thing??

[cwa46]

I have been arguing that ground probes do not improve your personal safety on several BB's. It is so ingrained in the hobby literature that few will listen. I have yet to get a reasonable explaination from an EE or other expert to explain how they help human safety. The article you have posted suggests that they may not help your fish either. Lots of junk science and I still don't know for sure if a probe is helpful to me or my fish. I agree that we need to use GFCI, though.

[SPasse]

Hi All,

Here is a thread on Reef Central where I discussed my perspective on ground probes.

http://www.reefcentral.com/vbulletin...ghlight=ground

I am an electrical/electronic design engineer. This includes design of electrical hardware to meet UL and other regulatory compliance standards.

My current job title is Senior Hardware Architect at T-NETIX INC, A specialized security service provider.

This is somewhat complex subject, and I agree with most of what is stated in the article that organicreefer sited. I do not advocate the use of a ground probe without a GFI as the current path that the author talks about can occur if a defective electrical device is used with a ground probe and no GFI is present to “turn off” the defective device.

My point is that if you use a ground probe and a GFI, that the problem is dealt with without a human having to provide the ground path.

I intend on writing to Robert Michelson and discussing this at length with him. But I would again point out, that his entire scenario is based on examples of using a ground probe without a GFI.

Regards,

Scott Passe

[Rin]

This is kinda long and I'm making a lot of assumptions where I don't have first-hand knowledge, but this is how I see it.

A grounding probe will help with personal safety. Will it guarantee your personal safety...No. Electricity follows the path of least resistance. A properly installed grounding probe will usually be that path rather than a body part. How many times do we reach into a tank to adjust something and happen to touch a reflector or a powerhead?

Because salt water flows through many tubes (and almost all are non-metallic), it generates potential energy (static). This static can build up into thousands of volts. I've personally never experienced that much in a tank. The most I was able to do through experimentation is 34. Accurately measuring that voltage is problematic so the 34 volts is a much lower reading than the actual voltage that probably existed in the salt water. Induced voltage from electrical equipment in the water may actually contribute more stray electricity than the actual water movement. I don't know, I've never tried checking that.

For the article to say that amperage is the killer is an oversimplification of the problem. High voltage at very little amperage can be just as deadly as very low voltage at high amperage. A more accurate statement would be flux. Flux is the amount of flow through a given area per unit of time. Amperage is somewhat comparable to flux so most folks stick with amperage.

I'm not suggesting that we can generate pools of voltaic destruction from simply stirring the water up a little bit, but these transient voltages might be enough to disturb our fish. There is a point were the voltage that builds up starts bleeding off in the form of electrical currents. This is due mostly to the ionic nature of our tanks.

I believe that most fish can sense these currents, it seems to be a part of their anatomy. Sharks are a very good example of fish adapted to detect these electrical currents. Land animals aren't as sensitive (bird on a wire), but try walking under high-tension electrical lines with a 20-watt fluorescent bulb in your hand. At night you'll be able to read by it. Now imagine your fish as little fluorescent bulbs swimming through an ungrounded fish tank.

I would rather that these voltages not build up in my tank so I'm sticking with my probe.

I will agree with the article in one respect. Don't use a grounding probe as a crutch for poorly maintained electrical equipment.

JMO

[SPasse]

Hi All,

I just sent an e-mail to the author of the article that Organicreefer posted.

I will update this thread with the outcome of our discussions.

Regards,

Scott

[cwa46]

Well I for one would like to finally understand. I have grounding probes in my tanks, but have never understood how they help with personal safety. If it is safer without grounding probes if there is no GFCI, I can't see how adding a GFCI makes the grounding probes a benefit to safety. I hope your discussions helps to resolve this issue.

[SPasse]

Hi All,

Well, I have received a very good response from Robert Michelson and there are two issues here.

1 Safety for the hobbyist.

2 Effects on the critters in our tanks.

These two issues are different and have potentially conflicting implications on the use of ground probes.

I am in the process of putting together a detailed response to Robert. To clarify the potential electrical path issues, I need to create schematics, etc to which I will imbed in a word document for our common reference.

After we come to a common understanding, I will post another reply with the conclusions. Be forewarned though, there are a number of potential scenarios and this issue may end up a “judgment call”.

I will need a few days to get this accomplished.

Regards,

Scott Passe

[dattack]

Wow. Very interesting article and it appears that he has the credentials (more than me ).

[cwa46]

Just keeping this post in sight.

[SPasse]

Hi All,

Well, as I indicated earlier, this has turned out to be a major project.

I am actually in the process of writing an article on the subject, so all I can say is “stay tuned”

Regards,

Scott

[cwa46]

Where will it be published?

[Ltspd]

Rin,
Well put.

[SPasse]

Cwa46

In an upcoming issue of the On-Line publication that Reef Central will be publishing.

I will post a synopsis to this thread before that article is published.

Regards,

Scott Passe

[afss]

speaking from personal experience. I had stray voltage in my tank./ my fish were jumpy, my corals lloked like s***. I tested and found stray voltage. I made myself a DIY grounding probe from a bike spoke and some wire. With in a few hours all corals looked better, and the next day the fish were starting to act normal again. I did test to see what was leaking, but couldn't narrow it down to any item. I do use a GFI also which has saved me a great deal of pain once already about 5 days after i installed it. I had my tank overflow (blocked overflow) and i ran over and grabed the plug to pul it out.. wet hands, wet feet from standing in the water.. not thinking as my tank flowed onto the floor. you get the idea. ZAP! split second.. just enough to let me know how stupid i had been and it shut of. IF you don't have a GFI you are foolish. they are less than 10 dollars, and EASY to install.
Scott

[cwa46]

Originally posted by SPASSE
Hi All,

Well, I have received a very good response from Robert Michelson and there are two issues here.

1 Safety for the hobbyist.

2 Effects on the critters in our tanks.

These two issues are different and have potentially conflicting implications on the use of ground probes.

I am in the process of putting together a detailed response to Robert. To clarify the potential electrical path issues, I need to create schematics, etc to which I will imbed in a word document for our common reference.

After we come to a common understanding, I will post another reply with the conclusions. Be forewarned though, there are a number of potential scenarios and this issue may end up a “judgment call”.

I will need a few days to get this accomplished.

Regards,

Scott Passe

How many more days Scott????

[cwa46]

As days go by!

[ww]

When I installed my ground probe in my tank, personal safety was not even a cosideration. I was only thinking about the stray voltage, which was a contributing factor in the HLLE on my Yellow Tang. I noticed a slight reversal of the HLLE after installation of the GP.

If your GFCI's are working correctly, it seems to me that that is all the personal protection you need. Of course, I could be very wrong....;)

[organicreefer]

stary current and hlle are only anectodotally linked....
in any case if you read the article i posted,it says the probe will make things worse for youre animals ....and it sounds like it might be correct

[shoeman]

I have to say that I have a weird feeling in my stomach right now. I have had to investigate several accidents with some having serious consequences even death and the most common thread is "I didn't think it was dangerous. Truth is, more people are killed with 110 Volts than any other. Anyone who works on a "live" circuit is taking their life in their own hands. Please for your sake, your families or your employers, turn it off. If I ever have to have work on a live system, it is with plenty of precautions and even then, we try every way to not do it. I do this for a living, and it isn't worth it. I am sure your employer doesn't condone it, and OSHA sure wouldn't. An OSHA investigation isn't pretty, and I quote" I'm not an (electrican) but I do quite a bit of electrical work at my job replacing (recipticals), Switches, ballasts, heating elements, etc. Now I work on live"hot" wires all the time. Yes your suppose to cut off power before you work on such items but many times I don't as I don't feel it's necessary if your not grounded. " Really man, do you think it is worth it? If I were to find one of my electricians doing this, he wouldn't work for me long. And for the not being grounded, how do you determine this? I only know of one way, and I am not sure you would go to that expense and trouble to change ballasts and such. I don't mean to flame you, but once you have to visit someone in the hospital, and see the after effects of an accident, you take it personal. Feeling comfortable around electricity is a grave mistake. No pun intended.;)