Arc Fault Ciruit Braker VS. GFCI Outlets. What is the Difference?

[Highland Reefer]

I am a contractor and I know that the new electrical codes require that all bedroom areas be put on ground arc ciruit brakers. I have talked to several electricians and the answer I get from them is ddaa. My question is what are the advantages of Ground Arc vs. GFCI regarding the reef system? Is there a possiblility that you could put a GFCI outlet on a ground arc ciruit and increase your protection? The gound arc circuit brakers are not cheap, running at about $50.00 each, but a few extra bucks for added protection would be worth it to me.

[jnguyen4007]

I found this link. It's pretty interesting. We recently installed 2 20 amps breaker and the outlets that connects to them are GFCI. Now I'm thinking that we might have to install these instead.

 

http://www.askthebuilder.com/320_New_Arc_F...e_Of_Mind.shtml

[Highland Reefer]

I found this link. It's pretty interesting. We recently installed 2 20 amps breaker and the outlets that connects to them are GFCI. Now I'm thinking that we might have to install these instead.

 

http://www.askthebuilder.com/320_New_Arc_F...e_Of_Mind.shtml

 

Thanks for the link. I am still confused as to whether just putting my reef system on a ground arc circuit is the safest way to go or whether the GFCI outlets does provide some sort of additional protection that the ground arc braker does not.

[ErikS]

I have talked to several electricians and the answer I get from them is ddaa.

Would seems like we could currupt a line from Kelly's Heros to answer this one -

 

"I don't know what makes 'em work, I just install 'em"

 

Arc Fault sense an arc in the wire, an intermittent short condition. A GFCI compares the inbound & outbound legs of the circuit - in the event of a mismatch it trips. The mismatch can occur without an arc condition (i.e. you as the path to ground). Example you're a nice path to ground with your hand in the tank - is this an arc? Nope = no trip on the arc fault breaker = you may die. For a GFCI this does cause a trip = you live.

 

Short version - one is designed to stop fires, the other to keep you from getting killed.............which is why one is code in bedrooms & the other is code in bathrooms where the bad juju of electricity, water, and a saline bag come together.

 

Different technology for different applications.

 

EDIT - have no idea if or why a GFCI wouldn't detect an arc condition (ain't gonna test it either).............experts?

Edited April 3, 2008 by ErikS

[Highland Reefer]

Would seems like we could currupt a line from Kelly's Heros to answer this one -

 

"I don't know what makes 'em work, I just install 'em"

 

Arc Fault sense an arc in the wire, an intermittent short condition. A GFCI compares the inbound & outbound legs of the circuit - in the event of a mismatch it trips. The mismatch can occur without an arc condition (i.e. you as the path to ground). Example you're a nice path to ground with your hand in the tank - is this an arc? Nope = no trip on the arc fault breaker = you may die. For a GFCI this does cause a trip = you live.

 

Short version - one is designed to stop fires, the other to keep you from getting killed.............which is why one is code in bedrooms & the other is code in bathrooms where the bad juju of electricity, water, and a saline bag come together.

 

Different technology for different applications.

 

EDIT - have no idea if or why a GFCI wouldn't detect an arc condition (ain't gonna test it either).............experts?

 

Can you install at GFCI outlet on a Arc fault circuit?

[jnguyen4007]

If I have to guess, I would say yes only because arc fault and GFCI work differently. But then again, I'm not an electrician.

[ErikS]

If I have to guess, I would say yes only because arc fault and GFCI work differently. But then again, I'm not an electrician.

Ditto

[Highland Reefer]

If I have to guess, I would say yes only because arc fault and GFCI work differently. But then again, I'm not an electrician.

 

I have found that the electricians can not answer this question. I think we need an electical engineer for this one. Do we have one in the house?

[Brian Ward]

 

I have found that the electricians can not answer this question. I think we need an electical engineer for this one. Do we have one in the house?

 

 

 

 

I'm half an electrical engineer.

 

GFCI and AFCI protect against completely different things. AFCI detects the "slow burn" condition where a wire has been nicked (nail, screw, etc) and there is a small arc that doesn't trip the breaker but can cause a fire.

 

GFCI detects an unintentional path to ground and kills the circuit when current is leaking. This leaking current typically occurs through a person.

 

So basically, AFCI protects against fires. GFCI protects against electrocution.

[Highland Reefer]

 

 

 

I'm half an electrical engineer.

 

GFCI and AFCI protect against completely different things. AFCI detects the "slow burn" condition where a wire has been nicked (nail, screw, etc) and there is a small arc that doesn't trip the breaker but can cause a fire.

 

GFCI detects an unintentional path to ground and kills the circuit when current is leaking. This leaking current typically occurs through a person.

 

So basically, AFCI protects against fires. GFCI protects against electrocution.

 

 

Brian,

 

Thanks for the info. Can you put a GFCI outlet on a ground arc circuit?

[Brian Ward]

 

Brian,

 

Thanks for the info. Can you put a GFCI outlet on a ground arc circuit?

 

 

As far as I know, yes.

[Rascal]

I think Davelin did a bunch of research on this when he was setting up his tank. You can find some of the discussion here: http://www.wamas.org/forums/index.php?show...p;hl=arc++fault.

 

If I remember correctly, he ended up using Arc-Fault breakers with GFCI outlets. I think the GFCI breakers are not as sensitive as the outlets.

[steveoutlaw]

Example you're a nice path to ground with your hand in the tank - is this an arc? Nope = no trip on the arc fault breaker = you may die.

 

 

Quit it with the negative waves, Moriarty!

[ErikS]

Quit it with the negative waves, Moriarty!

 

 

"........60 smart comments I can get just about anywhere......................ya schm*ck......."

 

[Scott_LM]

GFCI only detect "Ground faults", meaning a short from the hot leg to the neutral leg will not be detected by the gfci. This is could occur with an appliance that has a two pronged outlet instead of a three (it can happen with 3 pronged outlets as well, but not as common). This is especially common for us, the powerheads and heaters we use often aren't grounded. Since the tank itself is not grounded, you have the potentially for a hot to neutral short which could ARC. arcing is when electricity "jumps" through air. Think of a spark plug or lightning. The arcing is at extremely hot temperatures and could cause of fire. This is where the arc fault comes in. It protects against these situations.

 

HTH, and I didn't read any of the referenced threads so sorry if this was said before. Also, this is MY understanding, so take it FWIW.

 

 

Scott

[CHUBAKAH]

Cliff,

Not sure which company makes your main panel, but Square D is now making a breaker that covers ARC and GFCI both.

 

I haven't seen them in the stores yet, but there in info on them on their site.

[Highland Reefer]

Cliff,

Not sure which company makes your main panel, but Square D is now making a breaker that covers ARC and GFCI both.

 

I haven't seen them in the stores yet, but there in info on them on their site.

 

Mark,

 

Thanks for the info. I have to check, but I think I do have Square D and will be checking into them.

[davelin315]

Hey Cliff, we should have spoken about this last night!

 

I have a Square D panel, but the only ones the Arc Fault were available on were the... homeline? Can't remember which model... anyway, I added a subpanel with the Arc Fault Circuit breakers and then ran each breaker to a set of 3 GFCI outlets, independently wired. It makes sense to have a dual breaker until you consider that the breaker tripping will turn EVERYTHING off, not just the offending device. With mine, if I get something wet, only two devices will trip at most. If there's an arc in the line, I do want everything to shut off, so that's why I opted for the Arc Fault breakers running to GFCI plugs. I had a fire last year on a GFCI plug in one of my daughter's bedrooms and it was caused by an arc in the light wiring. It didn't trip and so I am trying to be as careful as possible now.

[Highland Reefer]

Hey Cliff, we should have spoken about this last night!

 

Dave,

 

I forgot all about it. They had said you did a lot of research, what did you find out about the combo brakers?

Edited April 7, 2008 by Highland Reefer

[davelin315]

They are not what I am looking for. I would suggest doing an arc fault interrupter and then run this to individual GFCI outlets. That's what I did. With this set up, it trips the whole thing in the event of an arc, but if a GFCI trips, which happens more regularly with any splashing, then your whole system doesn't shut down. It's also substantially cheaper. The use dictates what you use, and I think that for aquariums, removing the risk of shutting off your whole system is much better than a drop of water shutting you down. If there's an arc, then the whole thing should shut down, much different situation.

 

As far as them not working together, I have heard the same thing, but then I have also read that they work together as well. I can attest to the fact that a GFCI will NOT trip with an arc. It's VERY bad when it doesn't trip... I had a fire in a tank because a wire arced, and then electricity kept on getting fed to it which in turn caught plastic on fire from overheating.

[Highland Reefer]

They are not what I am looking for. I would suggest doing an arc fault interrupter and then run this to individual GFCI outlets. That's what I did. With this set up, it trips the whole thing in the event of an arc, but if a GFCI trips, which happens more regularly with any splashing, then your whole system doesn't shut down.

 

 

 

Thanks Dave. Since I already have my reef on ground fault, all I have to do is install the ground arc braker. My bedrooms are already on ground arc and I am thinking about installing ground arc on the remaining 15 & 20 amp circuits. I don't know about the 30 & 50 amp circuits (dryer, stove, well pump & AC)?

[tbittner]

To add a question to this discussion, I've been told by an electrician that I shouldn't put my pumps on a GFCI circuit because they will cause it to trip frequently. I'm currently running (all sequence pumps) a Barracuda, a Hammerhead, and two snappers. What's everyone opinion on this?

 

I can change it but I ran 10 gauge wire to outlets mounted at the bottom of the ceiling and connected the wire to 30amp breakers (not GFCI, just normal breakers). Then I extended the cords to reach these outlets. Granted, the pumps themselves could still get wet but I tried to keep the connections far from water.

 

And wouldn't a short through water to ground be considered an arc fault?

[davelin315]

I have yet (knock on wood) to have any submersible or external pump trip a GFCI. The one thing that I have had trip it is when water was splashed onto a ballast by mistake. I don't agree with your electrician's point of view.

 

As far as the current in water, I don't believe it's the same thing as an arc, but I'm not an expert on this.

[tbittner]

Thanks Dave. I had no idea and I didn't want to take a chance of walking out the door, going to work, and coming home 9 hours later to find I didn't have any circulation in the tank so I didn't install them. It's easy enough to switch them out though.

 

All my other stuff are on GFCI breakers though. But the pumps, imho, being that they are sitting at the base of 100g's of water in the sump, well, it just seems scary to not have them on a GFCI circuit.

[BeltwayBandit]

I am not exactly an electrical engineer (although I did play one for the government for 5 years), so I do know something... I agree with what has been said earlier in this thread. Arc fault and ground fault are two different scenarios, both of which are not uncommon with reefkeeping. I too experienced an arc fault in a lighting harness that did not trip a GFCI. The only thing that saved me from a major fire was coming home and smelling the burning plastic in time to unplug the lights. In my opinion, Dave's approach -> arc fault breakers and gfci outlets is the safest way to go. GFCI outlets are only about $14/each. If you go with a gfci/arc fault breaker you will take your whole system down with a fault. IMO ground faults are more common in our equipment, but arc faults will burn the house down. Taking down a subset of the aquarium for a ground fault and the whole shebang with an arc fault is the way to go.

 

My recommendation is to wire the system on an arc fault breaker (two would be better) and then individual gfci outlets is the safest option. The GFCI is a passive device, sensing current on the hot and neutral but not interfering, having one downstream of an arc fault breaker should not be a problem.

 

BB