Warning - Page 5

banditpowdercoat · #41 05-13-2012, 03:28 AM

A AFI would offer more protection, but I think one needs both?. A GFI will only trip if it senses current going to ground, not back on the neutral. One can have a short on a GFI, between the hot and the Neutral and it not trip. Conversly, a AFI only trips when it senses an arc. Be it to ground or neutral. Most cases a AFI would work. Not on halide lights, I'm not sure. But say a pump leaks some to the tank, a AFI won't pick that up, a GFI will. AFI's can also trip by just switching or unpluging components. Heaters can sometimes trip them as well.

Like everything in this hobby, nothing is foolproof

Doug · #42 05-13-2012, 02:22 PM

Quote:

Originally Posted by banditpowdercoat

A AFI would offer more protection, but I think one needs both?. A GFI will only trip if it senses current going to ground, not back on the neutral. One can have a short on a GFI, between the hot and the Neutral and it not trip. Conversly, a AFI only trips when it senses an arc. Be it to ground or neutral. Most cases a AFI would work. Not on halide lights, I'm not sure. But say a pump leaks some to the tank, a AFI won't pick that up, a GFI will. AFI's can also trip by just switching or unpluging components. Heaters can sometimes trip them as well.

Like everything in this hobby, nothing is foolproof

Yup, they wont fire halides. And yes, they do sometimes, {not often}, trip when pulling a plug. My home has AFI/GFI as standard breakers for both bedrooms and bathrooms. I believe its code here but not sure.

My office/fishroom, has that receptacle plus I installed a separate dedicated 15a line with its own GFI.

StirCrazy · #43 05-13-2012, 02:27 PM

Quote:

Originally Posted by banditpowdercoat

A AFI would offer more protection, but I think one needs both?. A GFI will only trip if it senses current going to ground, not back on the neutral. One can have a short on a GFI, between the hot and the Neutral and it not trip. Conversly, a AFI only trips when it senses an arc. Be it to ground or neutral. Most cases a AFI would work. Not on halide lights, I'm not sure. But say a pump leaks some to the tank, a AFI won't pick that up, a GFI will. AFI's can also trip by just switching or unpluging components. Heaters can sometimes trip them as well.

Like everything in this hobby, nothing is foolproof

actualy a GFI measures the difference between the hot and the nutral, doesn't measure the ground at all. so this is wrong.

An arch fault breaker is esentualy useless on a fish tank unless you have an animal that chewes cords, especialy if you have MH lights, and I recomend against having them on anything important as they frequently have false positive trips. they are still trying to design a more reliable arc fault. It does pee me off that they made a misfunctioning componant code, hopefully they will come out with a more reliable version soon.
basicly if you have an electric motor, MH lighting, or any old school relays don't use Arc fault..

Steve

banditpowdercoat · #44 05-13-2012, 03:17 PM

Quote:

Originally Posted by StirCrazy

actualy a GFI measures the difference between the hot and the nutral, doesn't measure the ground at all. so this is wrong.

An arch fault breaker is esentualy useless on a fish tank unless you have an animal that chewes cords, especialy if you have MH lights, and I recomend against having them on anything important as they frequently have false positive trips. they are still trying to design a more reliable arc fault. It does pee me off that they made a misfunctioning componant code, hopefully they will come out with a more reliable version soon.
basicly if you have an electric motor, MH lighting, or any old school relays don't use Arc fault..

Steve

No, I'm not wrong. It measures the difference between Hot and neutral, yes. So if it leaks to ground, it sees a difference. if the circuit is normal, or even if device has an internal short to neutral, it will not trip. Current flowing in the hot lead, equals current flowing on the Neutral. Only other place it can go is ground.
I mighta worded it a little funky, but by sensing the current to ground, it uses the imbalance of the H-N wires

And yes, in all new construction or wiring reno's, AFI is code in BC for bedrooms and bathrooms.

justincgdick · #45 05-13-2012, 04:18 PM

Being electrician, I would not bother with the arc fault. The gfi will be your first line and the breaker will trip if you short something.

kole · #46 05-13-2012, 04:48 PM

I read somewhere, probably here on canreef, that if you have gfci's then you need to have a grounding probe in the tank as well. What about the question I asked about the gfci preventing fires in the situation like what happened to the op. I don't think they are intended for that sort of protection more for personal protection when working around water with electricity. By the way I not arguing anything here. Since we have some electrician's posting I would like to get the information from those who would know more about these things than me.

banditpowdercoat · #47 05-13-2012, 04:55 PM

In most all cases, yes a GFI will trip and prevent fires. As a water leak onto the plug most times will short out the ground too. I was just stating that it's not foolproof. It has to short between hot and ground to work. And yes, to have the GFI protect tank water, the water should be grounded with a probe.

Plug placement and drip loops still are best practice too. never have powerbar just lying on floor or shelf plugs up. If it must sit on floor or shelf, lay it on its side atleast so water can't drip directly into it

kole · #48 05-13-2012, 04:57 PM

Quote:

Originally Posted by banditpowdercoat

In most all cases, yes a GFI will trip and prevent fires. As a water leak onto the plug most times will short out the ground too. I was just stating that it's not foolproof. It has to short between hot and ground to work. And yes, to have the GFI protect tank water, the water should be grounded with a probe.

Plug placement and drip loops still are best practice too. never have powerbar just lying on floor or shelf plugs up. If it must sit on floor or shelf, lay it on its side atleast so water can't drip directly into it

Thanks I wasn't sure if you had directly answered my other post. Good info for everyone to know.

justincgdick · #49 05-13-2012, 04:59 PM

Like was said above, an arc fault would technically be best to prevent the fire like the OP had, but arc faults aren't perfect. You can "trick" them by accident when motors start up, etc. So while they do what we want, they also do what we don't want.

I myself would go with multiple breakers/ circuits for a big tank, surge protection (to protect a lot of valueble stuff), and multiple GFCIs.

mike31154 · #50 05-14-2012, 04:14 PM

GFI device will trip without having a ground as well. That's the whole premise behind it actually protecting us from shock. If you contact the hot lead of a GFI protected circuit & sufficient current leaks through your body to an external ground, like a wet floor, it will trip since some current is going through your body instead of back through the neutral wire. The GFI current threshold is so low that it will trip the circuit before the current through your body is enough to be harmful. This will happen whether there is a ground prong present on the electrical receptacle or not. It's also why it's acceptable (even advisable for personal protection) to replace an old two prong receptacle in older circuits using no ground wire with a 3 prong GFI receptacle. The ground prong in this case is not connected to anything, but the GFI can still protect you by sensing a current leak through you to another grounded surface. Hope that makes sense.