Electrical question - arc fault vs ground fault...
- Thread starter 20 20
- Start date
jelwyoming
JELWYOMING
Most arc fault devices include ground fault protection as well. Arc fault protection is looking for wiring becoming loose and is required to be installed in certain living spaces such as bedrooms in many states. I do not see the benifit of that protection for an aquarium application. GFI will do fine and will be less expensive. If you find a unit that does both for the same price, it won't hurt.
TheVillageIdiot
New member
i think you can get 20amp GFCI breakers, might end up saving you a little coin if you're planning on having a lot of GFCI outlets.
No, not many outlets. Basically what I'm reading here is to use GFI instead of AFI. I had been given advice elsewhere that AFI is important to use in an aquarium setting, since over time the salty humidity can cause some wires to corrode, causing fires. Doesn't happen a lot, but once is too much. So, I was planning on using AFI breakers, in fact, I've already bought them. Then I was thinking about GFI, and didn't know if the AFI breakers automatically provide GFI protection, the breaker 'package' doesn't state that. So, I figured I would add GFI by using GFI outlets. So, are you saying that if I have GFI circuit protection I don't need AFI? It sounds like they protect against different issues. If that's so, the best of both worlds is to have both AFI and GFI protection. Barring being able to find breakers that have both built in, can I simply add GFI outlets to an AFI protected circuit, or should that not be done?
SO confused...
SO confused...
Thats it entirely.
GFCI is designed to protect ( not completely prevent ) electrocution. At a high level it detects differences in the amount of electricity going down one side of the circuit and coming back the other and if they differ figures its going somewhere else ( ground fault ) and breaks the circuit.
AFCI is designed to detect arcing from loose connections, nail punched through insulation etc. In those cases the arc can be enough to start a fire but not enough amperage draw to trip a normal breaker. It doesn't address electrocution issues.
For wet environments GFCI is what you would want. Keep in mind though that when troubleshooting you have to reset the GFCI interrupt. If the GFCI protection is at the breaker then you have to keep running back to the panel. If its at the first outlet in your series but say in the same room you get the same protection but don't wear out your shoes running to the electric panel so much.
jelwyoming
JELWYOMING
Again, many of the currently available AFI breakers do both types of protection.
I'm still not sure if it's 'valid' to run GFI outlets on an AFI protected circuit. If the AFI breakers I have also have GFI protection, I'm all set. If they don't , will hooking up GFI outlets work? Meaning, Can I actually plug stuff into it and have them work without tripping either the AFI breaker or the GFI outlet? And I won't be starting a fire? 
jelwyoming
JELWYOMING
Here is an excerpt from a government publication;
AFCIs vs. GFCIs
The AFCI should not be confused with the GFCI or ground fault circuit interrupter. The GFCI is designed to protect people from severe or fatal electric shocks while the AFCI protects against fires caused by arcing faults. The GFCI also can protect against some electrical fires by detecting arcing and other faults to ground but cannot detect hazardous across-the-line arcing faults that can cause fires.
A ground fault is an unintentional electric path diverting current to ground. Ground faults occur when current leaks from a circuit. How the current leaks is very important. If a person’s body provides a path to ground for this leakage, the person could be injured, burned, severely shocked, or electrocuted.
The National Electrical Code requires GFCI protection for receptacles located outdoors; in bathrooms, garages, kitchens, crawl spaces and unfinished basements; and at certain
locations such as near swimming pools. A combination AFCI and GFCI can be used to satisfy the NEC requirement for GFCI protection only if specifically marked as a combination device.
Note the last line.
AFCIs vs. GFCIs
The AFCI should not be confused with the GFCI or ground fault circuit interrupter. The GFCI is designed to protect people from severe or fatal electric shocks while the AFCI protects against fires caused by arcing faults. The GFCI also can protect against some electrical fires by detecting arcing and other faults to ground but cannot detect hazardous across-the-line arcing faults that can cause fires.
A ground fault is an unintentional electric path diverting current to ground. Ground faults occur when current leaks from a circuit. How the current leaks is very important. If a person’s body provides a path to ground for this leakage, the person could be injured, burned, severely shocked, or electrocuted.
The National Electrical Code requires GFCI protection for receptacles located outdoors; in bathrooms, garages, kitchens, crawl spaces and unfinished basements; and at certain
locations such as near swimming pools. A combination AFCI and GFCI can be used to satisfy the NEC requirement for GFCI protection only if specifically marked as a combination device.
Note the last line.
You have to have a GFCI. There can be no exception to this if you care about your safety at all. If you care about burning down your house put in the arc fault. There is more need for an arc fault on an aquarium circuit that any other I can think of. Loose wiring in metal halides, salt creep into connections, vibration from pumps working at Chinese wiring... I cannot even think of how many ways you can get a loose wire in all the stuff on a reef tank.
OK, I know I'm really an anal NPB (nit-picking-b*st*rd), but, that line could be interpreted different ways. I read it to mean "the 'combination' device will only provide GFCI protection", so it's not talking about a separate AFI breaker and GFI outlet combination. The AFI breaker's I have say nothing about GFI, so I'm going to assume they don't provide GFI protection. So, my question still remains (at least I don't think it's been answered yet):
If I set up my circuit with an AFI breaker that doesn't have GFI protection, and then use a GFI outlet, WILL THAT WORK?
Meaning, Can I actually plug stuff into it and have them work without tripping either the AFI breaker or the GFI outlet? And I won't be starting a fire? Damn, I AM anal, ain't I?
jelwyoming
JELWYOMING
Yes you can, however from experience as an electrical contractor, you can avoid many compatibility issues with fault protection equipment by using the single device, I would consider a single combination breaker. You can try using what you have, but you may end up with issues where the devices actually interfer with the operation of the other. Then again, if you already have it, you may as well try. It will not burn anything up if installed per directions.
jelwyoming
JELWYOMING
If I remember right, Homeline is a SquareD product. Look at the box and see what type of breaker it accepts. SquareD does make the combination units. They may still be called AFI units, but offer the dual protection. Home Depot, or better yet, your local electrical suppy store, can probably tell you exactly what you need.
hllywd
Premier World Traveler
I've never seen the combo unit, seems like a good idea for our application.
20 20, I would advise you to check with your local code authority as a first stop. If there isn't one and you really want to know the nuts of your project you should check with a licensed electrician. Personally I think the GFCI is more important from the standpoint that if you're dead you probably won't care if the house burns down... The downside is that in my experience GFCIs will sometimes trip for no apparent reason. This happened to me earlier in the year when I as 600 miles from home at the Bristol race and my wife called wanting to know why the tank lights on.
It cost me all the frags I had just aquired at the C-Sea swap a really healthy PBT, a CBS and who knows what else... A power out alarm is a must.
Hope that helps,
Tim
