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Tammy3770 
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 Topic: voltage in my tank
Posted: February 07 2006 at 12:00pm |
yes, I'm an electrician.
But this has me stumped. Mainly because I don't know if this is "normal"
PLEASE NOTE: I have never tested for voltage on my tank ever.
ok , I have 3 power strips on two separate breakers.
yesterday after shampooing my carpet and while it was still wet, I stood barefoot on the carpet and reached in to my tank with a cut on my hand and got shocked. I am familiar with the feeling of current so I went for my fluke right away. 24 volts!
the easiest thing I could think of was to determine which power strip the culprit was plugged in to by 1) unplugging the entire power strip. 2) testing voltage to determine a change.
I unplugged one the voltage went down to ~16volts
unplugged two the voltage went down to ~8 volts
unplugged three the voltage went down to 0 volts.
ok so it seems I have some voltage leak from each power strip so that means I have at least 3 culprits, Right?
SO.. I unplug 2 power strips and start going through the cords one by one on the power strip that is plugged in. so I get 2-4v off of everything I plug in. It seems everything that is in contact with the water is leaking voltage (and it is really adding up)
ok, well all these power strips are the same brand so maybe it is something internal to the pwr strips. I unplug all power strips. I test for voltage in water, 0 I take the heater (which I labeled as leaking 4 v ) I plug it in the WALL, test for voltage----- yep 4 volts.
Ok so my 1940's apartment complex has what is known as "poor power quality" meaning there is some voltage between the neutral and ground,,,,,,,, I test it, ZERO volts. (that's not it whattheheack)
so I guess what I'm asking: is stray voltage in your tank normal, and is it directly proportional to the number of things plugged in? I guess I need a grounding probe, Huh?
I don't think EVERYHING in my tank has gone BAD after TWO YEARS.
I dont think I would have felt the shock if it wasn't for the wet carpet and the cut on my hand.
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Adam Blundell
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Posted: February 07 2006 at 12:12pm |
so I guess what I'm asking: is stray voltage in your tank normal, and is it directly proportional to the number of things plugged in? I guess I need a grounding probe, Huh?
Yes. It is normal. Some items do produce more than others, it isn't just a number of plugs type of thing. I've tested many tanks and your reading of 24 volts is low. Most run around 80.
I've often felt "the buzz" when touching the water and my light reflector at the same time.
There is another surprise around the corner for you. Should I wait until you get really surprised, or spoil it and tell you now???
Adam
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Tammy3770
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Posted: February 07 2006 at 12:31pm |
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is it about the grounding probe???
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Adam Blundell
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Posted: February 07 2006 at 12:32pm |
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Tammy3770
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Posted: February 07 2006 at 12:34pm |
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seti007
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Posted: February 07 2006 at 12:37pm |
Use a titanium bicycle spoke to make a DIY grounding probe.
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unixnum1
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Posted: February 07 2006 at 12:40pm |
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Do they ground the outside case on the titanium heaters?
If so, then that would be a useful grounding rod. 2fer
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220G with 30G sump, SPS/LPS. RoboTank Controller. =====================================
If life is a bowl of cherry's,
why am I always the stem?
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Tammy3770
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Posted: February 07 2006 at 12:45pm |
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Do they ground the outside case on the titanium heaters?
If so, then that would be a useful grounding rod. 2fer
I'll have to check on that, but Its a good Idea.
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Adam Blundell
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Posted: February 07 2006 at 12:50pm |
I'll bet that after you put in the grounding probe, you'll still get a reading of 24 volts. Then you'll really be confused. Just like me.
Adam
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unixnum1
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Posted: February 07 2006 at 12:51pm |
I remember I had a pump case crack and I had a good 100+ zapping me.
It took me a few zaps to track it down  .
What I couldn't figure out though, is why my GFI wasn't tripping????
I even replaced it thinking it was broken but it still won't trip.
Not enough V?
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220G with 30G sump, SPS/LPS. RoboTank Controller. =====================================
If life is a bowl of cherry's,
why am I always the stem?
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Tammy3770
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Posted: February 07 2006 at 1:17pm |
I'll bet that after you put in the grounding probe, you'll still get a reading of 24 volts. Then you'll really be confused. Just like me.
Adam
It hit me as I was changing the loads of laundry:
because your tank has a different potential than your house ground?
I'm sure its not voltage but current that one had to worry about. let me set my fluke to Amps......nope,, no amps. not even a milliamp.
I'm good.  "don't worry...beee happy!"
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Summertop
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Posted: February 07 2006 at 2:22pm |
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So, sounds to me like the solution is dry your carpet.
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Shawn Winterbottom
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Tammy3770
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Posted: February 07 2006 at 2:46pm |
 Summertop wrote:
So, sounds to me like the solution is dry your carpet. |
yea Its dry now, 
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Will Spencer
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Posted: February 07 2006 at 3:03pm |
OK, I'm not an electrician, but I know some of the words.
I understand that you can have voltage in your tank, but without amperage it doesn't necessarily become dangerous. Do I have this right?
My question then is why can you still feel it? Doesn't it need some "power" behind it to make it felt?
All I know is I've been zapped by almost every tank I've ever dealt with at one time or another for one reason or another. One jolt from a friends tank threw me across the room.
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sshm
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Posted: February 07 2006 at 3:37pm |
Voltage in the tank can be from any source. An insulated box filled with
saltwater is like an antenna, a fluorescent tube somewhere in the room
will induce a voltage in the saltwater tank (since the fluorescent tube is
operating at 60Hz). Moreover, powerheads, ballasts, pumps, stuff which
have a transformer coil can also induce a voltage due to induction. A
voltage by itself doesnt do anything, your tank can be at 5 million volts
but if there is no differential, then voltage is meaningless. Think of it like
a ball place at a height of 5 feet, if there is no path for the ball to roll
down it will stay at 5ft no matter what. The moment it has a path it will
try to reach lower ground. the same with voltage or more accurately,
potential. If your aquarium is at 5 or 5 gazillion volts, it will always try to
reach 0, but it needs a path to do so.
If there is any amount of voltage in your tank it doesnt matter until there
is path provided for the current to flow. If you dip your hand in then the
current will flow through you to reach the ground. If that path is through
your heart, then well, bye-bye, you will be dead before you hit the ground
(no pun intended).
EDIT: edit for the usual caveat, anything I say on any topic anywhere,
anytime is my opinion only, so take it at your own risk  , -warning
done.-
Edited by sshm
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sshm
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Posted: February 07 2006 at 3:48pm |
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Kevin, yes it is definitely possible to get zapped and not trip the GFCI.
Please get rid of the faulty equipment, if your GFCI is fine. Here is why it
can be dangerous:
1) A GFCI senses an imbalance between the 'hot' wire and the 'neutral'
wire. Normally, the current leaving the hot wire will be equal to the
current entering the neutral wire.
2) If there is a short to ground, then the current leaving the hot wire will
run through to the ground (if it is a person who has provided the short
path through his/her body, then the current is coursing through his/her
body to reach ground)
3) The GFCI senses this imbalance and trips provided any of the two
criteria are met ie usually a time limit criteria and a difference limit.
4) Even in the normal case, you will get a shock before the GFCI trips,
because the GFCI cannot predict an imbalance, it has to sense it first.
4) If the GFCI hasnt tripped then the current path is from the hot wire,
through you and then to the neutral wire, therefore there is no imbalance,
but you will still get zapped. This is by no means any less dangerous than
a current path from hot to ground.
Remember that current will always find the shortest least resistance
pathway. Therefore, if the path touching the hot wire is your index finger
and the path touching the neutral is your thumb, then the current will
flow in the loop between your thumb and index finger, it will not flow
through your thumb all the way around your head and back to the index
finger. However, if your right hand is touching the hot and your left foot
is touching the neutral wire, the GFCI wont trip you will get a nasty shock,
moreover, the current path makes it likely that it will flow through your
heart.
The thing to remember is that most people think that the human body is
not a good conductor. Actually, it is a very good conductor given that we
are mostly water. The thin layer of dead skin, the epidermis, acts as an
insulation. But we also have sweat pores which act as shunts. If you have
your hands wet the resistance drops down dramatically, salt water even
more so.
EDIT: edit for the usual caveat, anything I say on any topic anywhere,
anytime is my opinion only, so take it at your own risk , -warning
done.-
Edited by sshm
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unixnum1
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Posted: February 07 2006 at 3:57pm |
Believe me, the pump is long gone  .
GFI is now more understood!
Since I provided the path from the hot wire to a different ground (the
house or different circuit), it couldn't detect the flow so it didn't
trip.
This will make me a little more cautious from now on.
Thanks much!
Also blood has alot of salt in it which also increases conductivity.
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220G with 30G sump, SPS/LPS. RoboTank Controller. =====================================
If life is a bowl of cherry's,
why am I always the stem?
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jfinch
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Posted: February 07 2006 at 4:08pm |
My question then is why can you still feel it? Doesn't it need some "power" behind it to make it felt?
Stand up and shuffle your feet around the room for a few minutes. Now walk over and touch the TV. Did you feel it? That's hundreds (maybe thousands) of volts but a very small amount of amps.
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sshm
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Posted: February 07 2006 at 4:12pm |
unixnum1 wrote:
Since I provided the path from the hot wire to a different ground (the
house or different circuit), it couldn't detect the flow so it didn't
trip.
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Yes, actually not a different ground but the path was probably between
the hot prong (the one which is typically wider), through you and then to
the neutral prong. Since the current leaving the hot prong was still the
same as the current entering the neutral prong, the GFCI didnt trip.
unixnum1 wrote:
Also blood has alot of salt in it which also increases conductivity.
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The lethal current dose is in the nanoamps range if the current has access
to blood directly. &nb sp;
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