Electrical Safety: GFCI, AFCI, Ground Probes

Turbo's Aquatics

Super Duper Member
View Badges
Joined
Jun 7, 2011
Messages
2,799
Reaction score
4,022
Location
West Des Moines, IA
Rating - 0%
0   0   0
Here is a write-up regarding Electrical Safety that was posted on our local club forum, I'm interested in any comments, corrections, or suggestions to this. I think it's pretty spot on, I'm an Electrical Engineer myself but that doesn't mean I am an Electrician.

Perhaps I can get a review on this from the Resident Electricians, the ones who were active in the Sticky Thread Your Resident Electrician for all your electrical questions! don't seem to be active anymore unless I missed one

Clarification of terms:

Receiving a "Shock" or "Small Shock" before a circuit protection device (such as a GFCI) kicks in and trips the circuit offline is not just like a prick of the finger, it will definitely get your attention. While it is highly unlikely that this shock will kill you, that doesn't mean it won't (I think of conditions like having a pacemaker or a specific health condition, or just flat out bad luck...anything is possible).

Getting electrocuted generally means the opposite: it's highly likely that this can/will kill you, and if you've been electrocuted and have lived to tell the tale, you can attest to this. I have a friend who got hit with 220V working on a stove and convulsed hard enough to break away from the circuit - lucky. When you stick your hand in a tank that is electrified and not protected, and you get electrocuted, it's probably more likely that your body will break away because you aren't holding on to a live wire that your muscles can't let go of...but that's only if you happen to fall away from the tank - if you fall toward it or into it - unlucky. You might as well be holding on to a live wire.

So if you choose to not run a GFCI at all, or maybe just not on the return pump - just make sure you understand the risk you are taking.

-------------------

The only thing they (GFCIs) protect is you. Which a GFCI will do better If you use them, you’ll never know that you have an electrical leak because the juice flows to the grounding probe. If you don’t have one, you feel that tingle when you put your hands in the tank especially if you have a small cut on your hand. If it's a dangerous level of amps (above 4-6 milliamps - not volts) the GFCI will trip instead, protecting you. With a grounding probe this will not happen. Now you know you need to isolate the problem piece of equipment and get it out. The current is still going to affect your livestock even if you have a grounding probe since they are now part of the closed circuit of electricity within your aquarium. If you have current in your tank it needs to be corrected. Stray voltage also messes with sensitive probes especially pH and salinity probes. There is a lot of debate on them I personally don't use them and don't recommend them.

Heres some cut and pasted info in different scenarios for you:)

Scenario 1. Hot line to water via submerged equipment. This is when a submerged piece of equipment like a powerhead, heater or UV lamp fails and the hot line of the power supply gets in contact with the water:

a) No GFCI and No Ground Probe.
As the tank is isolated from ground via plastic piping and wood stands the water becomes energized to 110 V but the main breaker does not trip as there is no current to ground. Fish has no problem because they are in a situation similar to a bird standing on a power line. This is a VERY DANGEROUS situation for the aquarist because as soon as you touch the water you get electrocuted as you become the path of current to ground. Breaker does not trip as there is not enough time for it to act or enough current to create enough heat. (They are slow trippers)

b) GFCI installed but no Ground Probe: Again nothing happen initially but the tank gets energized to 110 volts. as soon as you touch the water the GFCI will trip within 5 milliseconds and below a current of less than 5 milliamps. You may feel a small shock but nothing enough to hurt. This is the safest situation for the tank critters but may still hurt the aquarist mainly if the GFCI is malfunctioning.

c) GROUND PROBE INSTALLED BUT NO GFCI (Our case of discussion in this thread): As soon as the device fails and a short circuit is established then current is established to the ground probe, current may or may not be high enough to trip the breaker. Fish and critters will die and corals will RTN. If the breaker does not trip (Which is most of the cases) the short circuit may not be noticeable and you will be at a loss of why your critters are dying, even if you touch the water you may not notice unless the ground probe is not making a good ground. (See also Scenario 3c below) This is also a dangerous situation for potential fire. The current could be high but not high enough to trip the breaker, wires heat up, insulation melts and they catch fire.

d) Ground Probe Installed and GFCI installed: As soon as the short circuit is established the GFCI will trip shutting down whatever equipment is connected giving you a physical indication there is a short and something bad for you to fix immediately. This is the safest situation for the aquarist but has the downside that if you are away from the tank for a long time the lack of operating vital equipment may put your critters at risk.

So under this scenario the safest for the aquarist is to use both a GFCI and a ground probe. The next safest is to use GFCI alone.

Scenario 2: Short circuit between hot line and neutral on submerged equipment:

a) No GFCI and No Ground Probe: device and line will over heat. if current is high enough breaker will trip but it may take some time 10 seconds up to 5 minutes depending on the quality of the short. Plastic parts or rubber seals on the device may melt creating a secondary short reviewed under scenario 1 and releasing toxic chemicals into the water also copper wire may get exposed also releasing copper sulphate and other copper compounds to the water. Large mortality of critter is most probable.

b) GFCI installed but no ground probe: GFCI will not activate even if a secondary short to water is created as the water is not grounded and there will be no leakage current to create a current un-balance between hot and neutral so GFCI will not be able to detect the situation. Here as in 2a above (as well as 2c below) you are dependent on the breaker.

c) Ground probe installed but no GFCI: Same situation as in 2a above but if a secondary short is created current will be established killing the tank inhabitants but just probably faster than the toxic chemicals or copper compounds. Here you are dependent on the breaker.

d) GFCI and ground Probe installed: If a secondary short is created this will be same as 1d above, GFCI will trip reliving both the short circuit and disconnecting the power to the device probably preventing or reducing the damage by chemicals or copper. If no secondary short develops again you depend on the breaker.

Here again the safest alternative will be GFCI and ground probe installed although will not be effective if a secondary short to water is not established. Note that as mentioned above a short from hot to neutral may create a fire as the wires may get hot enough to initiate it.

There is a new device in the market that will replace the breaker and designed for this kind of fault. It is called an AFCI (Arc Fault Circuit Interrupter) This device will fulfill the functions of a breaker but while a breaker rely on the heat of the wires created by the short circuit which makes it slow an AFCI detects the arc on the short circuit acting immediately. For full protection under scenario 2 an AFCI in the main panel plus a GFCI in the outlet and a ground probe in the tank will provide for full protection.

Scenario 3: Short circuit from hot to a metal part of a non-submerged device and there is no current to trip the device as the metal body is not grounded: This is typical of a lighting fixture to whom one of the light bulb wires touches the reflector or the metallic hood or when some of the wiring of external pumps short to the pumps body and the body of the pump is not grounded.

a) No ground Probe and no GFCI installed: As the fault is external to the aquarium the aquarium does not get energized and no effect. If you touch the device depending on how well insulated from ground you are (rubber soles vs bare foot, globes vs bare hands etc) you may just get jolted or may get electrocuted.

b) GFCI installed but no ground probe: If you are touching the water and touch the device the GFCI will trip even if the short is within the external device. Typical of this fault is when a terminal on a lamp in the hood gets shorted to the hood itself via salt creep. you are working in the water while you touch the hood with your arm or shoulder.

c) Ground probe and no GFCI: This is one of the the main reasons why probes shall not be installed unless a GFCI is also installed. The water will be perfectly grounded. If you are working in the water and touch the device you will get badly shocked or electrocuted even is you yourself are electrically insulated by the use of rubber soles or such.

d) Ground Probe and GFCI: GFCI will trip as soon as you touch the body of the device saving you once more.

For this scenario the safest will be 3b and 3d above. To make this a really safe situation: i) Use only devices installed with three prong plugs they usually ground the body using the third prong.
ii) Replace the plug and wire of any device to a three pong plug and connect the green wire to the body of the device. (The metal hood, the body of the ballast, the casing of the pump etc.)
Note that many power heads only use 2 prong plugs, if possible select one with three prongs. (Maxi jets used to have three prong wires and plugs but they were replaced with a lighter insulation wire and two prong plugs. It is still unclear to me why. Cost?, Did not want to potentially ground the water? Only they know)

Scenario 4: Short from hot to neutral or grounded body of an external device:

Under this scenario for all cases you will be dependent on the breaker. If the current is high but the breaker is slow on acting there might be a fire. The use of an Arc Fault Circuit Interrupter instead of a breaker will reduce the fire possibility.

Scenario 5: Short from Neutral to water: As usually the neutral wire is grounded either at the outside were the wires enter the house or at the main nothing happens unless this neutral grounding is not perfect some small voltage may develop creating the following situation:

a) No GFCI and No Probe: nothing will happen, you may detect small voltage of the water to ground, if you touch the water you may feel a small shock if you are not insulated enough.

b) GFCI but no ground probe: if you touch the water and the voltage is high enough to generate at least 5 milliamps the GFCI will trip.

c) Ground probe but no GFCI: The small voltage may create a permanent small current, this may be enough to start killing the most sensitive critters, (Pods and Snails) and create coral RTN over long term.

d) GFCI and Ground Probe: same as 5b above. If the current is below 5 milliamps it may still create a small current which may affect the tank inhabitants but in a lesser degree given the smaller current level than 5c above.

So in summary overall the safest for the aquarist will be the installation of AFCI, GFCI and Ground Probe. The safest for the inhabitants will be AFCI and GFCI without ground probe. This is the reason why many aquarist do not use ground probes (but will always use GFCIs) specially traveling ones that stay away for extended periods of time. If you have a remote alarm system installed that may page you or send you an E-Mail in case of a fault (Like the aqua controller from Neptune Systems) you shall have no doubts and have your Probe installed with your GFCI's)

Opposite the most dangerous situation is not having at least a GFCI. By the way many states, city or county electrical codes require installation of GFCIs on any location where electrical equipment may be exposed to water like outdoors, kitchens, bathrooms, aquariums, spas etc. If this is the case and there is an accident or fire the insurance company MAY NOT PAY. so be warned.

-------------------
 
Last edited:
OP
OP
Turbo's Aquatics

Turbo's Aquatics

Super Duper Member
View Badges
Joined
Jun 7, 2011
Messages
2,799
Reaction score
4,022
Location
West Des Moines, IA
Rating - 0%
0   0   0
Throw in an AFCI breaker and a controller with battery backup and a wifi module and everything it protected...right? :D
 

billw

Acroholic in Training
View Badges
Joined
Jan 23, 2010
Messages
213
Reaction score
99
Location
Lexington Ky.
Rating - 0%
0   0   0
Or remove the grounding probe when no one will be near the tank for an extended time! Don't forget to reconnect the probes first thing upon return or you may get an unexpected welcome home :).
 

Harold Green

Well-Known Member
View Badges
Joined
May 21, 2014
Messages
812
Reaction score
280
Location
cleveland tx.
Rating - 0%
0   0   0
I have to disagree with the statement about the gfci only allowing a slight shock. The several cycles of current that pass through before it trips can be as painful as a full fledged shock only not usually fatal. Don't think it will stop you from being shocked. There's a difference between being electrocuted and being shocked. Electrocuted means death. Shocked does not. As a retired electrician I'm less afraid of being shocked by a tank than I am about a gfci tripping out while I'm away. They are notorious for tripping just because of air or ground humidity so it's far more likely they will trip when there's no problem than when there is.
 
OP
OP
Turbo's Aquatics

Turbo's Aquatics

Super Duper Member
View Badges
Joined
Jun 7, 2011
Messages
2,799
Reaction score
4,022
Location
West Des Moines, IA
Rating - 0%
0   0   0
Good point @Harold Green, I can update the post to make this clarification.

On the nuisance tripping, this can be reduced significantly by getting a good quality (heavy-duty / motor-rated) 20A GFCI receptacle instead of the cheapest one you can find, which is usually a 15A one and low build quality.

The NEC now requires (recent change) all sump pump circuits to be on a dedicated GFCI receptacle. Also, deep freezes in garages. There have been many local code boards that have excluded this, because no one wants their sump pump tripping out and flooding their basement, or their deep freeze tripping out and melting all their food. But the concern for life was considered higher. The remedy is to make sure that you are using a heavy-duty receptacle that is rated for motor use.

Many small motors and compressors will tend to trip a cheap GFCI because of the starting (inrush) current, maybe not right away, but after a few years of use, the cheap ones don't work quite as well (that's why you're supposed to test them monthly - to make sure they #1 trip and #2 reset). Motor-rated or heavy-duty GFCI receptacles should not trip unless there is a problem (fault), and then they're supposed to protect you, above all else.
 

TheClark

Active Member
View Badges
Joined
Aug 16, 2013
Messages
386
Reaction score
58
Location
Kelso, WA
Rating - 0%
0   0   0
One thing worth mentioning, the possibility of fire is very real with all of our saltwater and electricity.

This is a follow up to some research after an extension cord fire caught me off guard. It erupted into flames in front of my eyes, quite alarming. This circuit had AFCI in the panel and GFCI at the receptacle but it did not prevent the fire.

205be6d2ccc00c66304608d71c105e87.jpg



Don't let this happen to you! Update to Combination AFCI (CAFCI) breakers or add one...

Even if your home has AFCI breakers, if they are from before 2008 apparently they won't protect against series arcs.



34063d1404321037-what-cafci-breaker-serial.jpg




Consider having your breakers updated, at least in the room where the aquariums are! Read more about CAFCI in this document:

http://static.schneider-electric.us... Fault Circuit Interrupters-AFCI/0760DB0204.p

Don't let this happen to you (I watched this plug erupt in flame after a quick jiggle...)

I also added an additional smoke detector right over the aquarium wiring for another level of protection if anyone is home.
 
Last edited:
OP
OP
Turbo's Aquatics

Turbo's Aquatics

Super Duper Member
View Badges
Joined
Jun 7, 2011
Messages
2,799
Reaction score
4,022
Location
West Des Moines, IA
Rating - 0%
0   0   0

Harold Green

Well-Known Member
View Badges
Joined
May 21, 2014
Messages
812
Reaction score
280
Location
cleveland tx.
Rating - 0%
0   0   0
The last thing I'd ever try to do is dissuade anyone from using protective devices, I merely want to let people know there is a downside to some devices. As a retired(40years)commercial electrician I've dealt with gfci's since the day they first hit the market. All outlets on commercial sites had to have gfci protection. It almost single handedly brought construction to a halt. Subs had to buy all new extension cords and couldn't run them on the ground or on the concrete without tripping the outlet. They have improved in quality over the years but they still have a major flaw. Wiring insulation in use is not good enough to prevent moisture from tripping out the outlets when there is really no short to contend with. My barn workshop has gfci's all over it. It also has a couple of non gfci's for loads that will trip the gfci(large table saw) after a few minutes of pulling full current through it(20amp gfci receptacle). Gfci's will always be a trade off and each must decide the value in their situation. Information is as always the key to deciding what's right for you and your family. Right now I have a gfci receptacle in the barn that I need to change out. They seem to have a fairly short life span where used heavily or exposed to damp air and the plugs eventually fail to reset and have to be replaced. I've seen regular outlets last fifty or more years but gfci's for all their costs and benefits seem to be relatively short lived as it is which most electronics. I've already replaced four out of ten in less than ten years and the rest are rarely used. It would be a real improvement if someone would sell a device you plug your loads into that instead of tripping at the point a gfci would, would light up a warning light that there's an issue.
 
OP
OP
Turbo's Aquatics

Turbo's Aquatics

Super Duper Member
View Badges
Joined
Jun 7, 2011
Messages
2,799
Reaction score
4,022
Location
West Des Moines, IA
Rating - 0%
0   0   0
Also what you can do to avoid the moisture issue is put your GFCI receptacle in another room, then tap off the load side of that and put your non-GFCI receptacles under the tank (downstream from the GFCI). This takes the GFCI+moisture out of the equation. It also makes it easier to test and replace your GFCI.

Also, don't they make non-receptacle GFCI devices that you can just put inline between the panel and the receptacles? Seems like these would last longer if there was no direct access to the interior of the device (no receptacle, no path for moisture)
 

Harold Green

Well-Known Member
View Badges
Joined
May 21, 2014
Messages
812
Reaction score
280
Location
cleveland tx.
Rating - 0%
0   0   0
Having a gfci breaker or plug in a dry location may extend the life of the gfci but does nothing to prevent the issue, which is the wire insulation on every device you plug in. I have several of the gfci cords where you only have a plug exposed to the air and the gfci is encased in the cord. Doesn't make any difference. The issue is still device cords and normal leakage when exposed to moisture. I suppose you could plug a back up power supply into a gfci and hope you notice it's tripped before the battery goes dead. I'm surprised the manufacturer of the gfci's recommend testing since the manufacturers of non gfci breakers recommends you replace a breaker after it trips as it weakens the breaker with each trip so that it trips at a lower and lower current flow.
 
OP
OP
Turbo's Aquatics

Turbo's Aquatics

Super Duper Member
View Badges
Joined
Jun 7, 2011
Messages
2,799
Reaction score
4,022
Location
West Des Moines, IA
Rating - 0%
0   0   0
I'm surprised the manufacturer of the gfci's recommend testing since the manufacturers of non gfci breakers recommends you replace a breaker after it trips as it weakens the breaker with each trip so that it trips at a lower and lower current flow.
I think they recommend testing "regularly" but I'm not sure there is anything that says you have to. However is there a difference between breakers and receptacles, related to the trip current you describe?

I've actually never heard that standard panelboard breakers should be replaced after they have tripped. I'm an EE, so was my dad and his brother. Not like that means anything but also we have several electricians in the family, and I've been known to do beyond the standard receptacle wiring. Like replacing a panelboard and running new feeders to a meter socket without having the utility company shut off the power. One-hand-behind-your-back kind of stuff, if you know what I mean.
 

yarddoctor123

Community Member
View Badges
Joined
Sep 22, 2014
Messages
88
Reaction score
9
Rating - 0%
0   0   0
Having a gfci breaker or plug in a dry location may extend the life of the gfci but does nothing to prevent the issue, which is the wire insulation on every device you plug in. I have several of the gfci cords where you only have a plug exposed to the air and the gfci is encased in the cord. Doesn't make any difference. The issue is still device cords and normal leakage when exposed to moisture. I suppose you could plug a back up power supply into a gfci and hope you notice it's tripped before the battery goes dead. I'm surprised the manufacturer of the gfci's recommend testing since the manufacturers of non gfci breakers recommends you replace a breaker after it trips as it weakens the breaker with each trip so that it trips at a lower and lower current flow.
Good to know! I've installed GFCI's for ponds with my landscape business, and never was told that with each trip/test it affects the load or life. Thanks for sharing!
 

revhtree

Owner Administrator
View Badges
Joined
May 8, 2006
Messages
47,603
Reaction score
85,991
Rating - 100%
1   0   0
Great thread bro!
 

alin2

Community Member
View Badges
Joined
Dec 19, 2014
Messages
94
Reaction score
42
Location
Chicago
Rating - 0%
0   0   0
Thanks for this thread. Very informative.

Is there really any advantage of installing GFCI receptacles over just putting a GFCI breaker at the panel?

Also, do GFCI breakers nuisance trip less frequently than receptacles? Do the breakers last longer than the receptacles?

Thanks in advance.
 

rygh

Community Member
View Badges
Joined
Feb 25, 2011
Messages
92
Reaction score
67
Location
CA. Bay Area
Rating - 0%
0   0   0
Some quick notes:

Mutiplie GFCI outlets wired in parallel can really help improve reliability.
If one triggers, it does not bring down every piece of equipment.
Especially nice when you have dual return pumps, each on different outlets.
But don't wire them in series!

Cheap surge protecting power strips with LED indicators can trigger GFCIs.
Or worse, have enough leakage to be just about to trip.
Happened to me, and I have heard about others with the same issue.
Some circuit in there was leaking to ground.
 

Mastering the art of locking and unlocking water pathways: What type of valves do you have on your aquarium plumbing?

  • Ball valves.

    Votes: 68 52.3%
  • Gate valves.

    Votes: 67 51.5%
  • Check valves.

    Votes: 33 25.4%
  • None.

    Votes: 29 22.3%
  • Other.

    Votes: 9 6.9%
Back
Top