Should DC Pumps like jebao need GFCI

Jyetman · 03/31/2014, 03:26 PM

Wondering should I buy another GFCI for my WP25 pump?

tkeracer619 · 03/31/2014, 03:33 PM

A GFCI will do nothing if the short is on the other side of a power supply. The pump will do whatever it does until the power supply fails.

They work for things like hair dryers getting dropped in bath tubs.

magnoliarichj · 03/31/2014, 03:35 PM

You use a gfi when ever an outlet is near water.

tkeracer619 · 03/31/2014, 03:42 PM

Again, it won't do anything past a power supply or ballast. If a halide falls into the water a gfci won't turn it off.

madean · 03/31/2014, 04:18 PM

True a gfci will not turn off a particular piece of equipment just because it falls into the water or if a power head cord is leaking current into the water. What it will (hopefully) prevent is you getting a shock from the leaky or faulty electrical equipment. Basically current flows from the hot wire then to the equipment and then back through the neutral wire. The gfci looks at the current flowing from the hot wire and the neutral wire. If the two numbers have a difference of greater then like 4 or 5 milliamperes then the gfci opens and prevents further current to the equipment. The reason why the gfci doesn't trip when current strays from the wires (it's intended path) is because the current still returns back to the neutral through the water. The gfci doesn't care where the current goes as long as it returns. You don't want to provide a path for the current to go to ground. In other words you stick your hand in the water and your bare foot. You now have provided a path for the current to go to ground. Now the gfci senses a difference from the current leaving the hot wire and what current is returning, if any, through the neutral wire in the gfci unit. It then trips. But in the previous example the gfci would not trip if the halide light fell into the tank, unless the halide was case grounded. If the halide light was case grounded the current would want to go to ground and a difference in current would be sensed and then the gfci would trip. Is it a good idea to have equipment that goes in water gfci protected, I would say yes. Is it going to protect you from a shock. Hypothetically yes. Well it should. I wouldn't want to be the test dummy to see if it works. I put faith in the fact that it works. Now do you need to buy another one depends on how it's wired. You can install a gfci outlet on the first string of outlets and the gfci will protect all the outlets down stream of the gfci. If this pump is going on a circuit that's different then the one you have the gfci already installed then yes you need another one. I quick and easy way to test to find out is to plug the pump into the outlet and then trip the gfci. They are marked "test" and "reset". When you push the "test" button the pump might turn off. If the pump turns off then the gfci protects that outlet. If it does not then that gfci does not protect this outlet. Be aware though that if that gfci does protect other outlets it will interrupt what ever is plugged into them.

tufkab · 03/31/2014, 06:28 PM

madean; please educate yourself further before giving others dangerous advice. A halide, specifically one with a magnetic ballast can kill you even plugged in to a GFCI.

Magnetic ballasts have no electrical connection between the input and the output. The only time that a magnetic ballast would ever trip a GFCI is basically a winding shorted to the case. On the output side, you could short the connection or even hook a phase straight to ground and the GFCI would not see anything. The magic of induced current !

As far as a GFCI for a DC motor; Not likely. The DC voltages and currents we're talking about don't really pose much of a danger.

GFCI outlets have their place; but you have to understand their limitations, a false sense of protection is the most dangerous part of working with electricity.

03/31/2014, 03:26 PM	#1
Jyetman Registered Member Join Date: Nov 2012 Location: Phoenix, AZ Posts: 1,712	Should DC Pumps like jebao need GFCI Wondering should I buy another GFCI for my WP25 pump?

03/31/2014, 03:33 PM	#2
tkeracer619 Registered Member Join Date: Jan 2006 Location: Westminster, CO Posts: 17,289	A GFCI will do nothing if the short is on the other side of a power supply. The pump will do whatever it does until the power supply fails. They work for things like hair dryers getting dropped in bath tubs. __________________ Hobby Experience: 9200ish gallons, 26 skimmers, and a handful of Kent Scrapers. Current Tank: Vortech Powered 600G SPS Tank w/ 100gal frag tank & 100g Sump. RK2-RK10 Skimmer. ReefAngel. Radium 20k.

03/31/2014, 03:42 PM	#4
tkeracer619 Registered Member Join Date: Jan 2006 Location: Westminster, CO Posts: 17,289	Again, it won't do anything past a power supply or ballast. If a halide falls into the water a gfci won't turn it off. __________________ Hobby Experience: 9200ish gallons, 26 skimmers, and a handful of Kent Scrapers. Current Tank: Vortech Powered 600G SPS Tank w/ 100gal frag tank & 100g Sump. RK2-RK10 Skimmer. ReefAngel. Radium 20k.

03/31/2014, 03:35 PM	#3
magnoliarichj Registered Member Join Date: Mar 2007 Location: florida west coast Posts: 1,455	You use a gfi when ever an outlet is near water.

03/31/2014, 04:18 PM	#5
madean Registered Member Join Date: Feb 2009 Posts: 994	True a gfci will not turn off a particular piece of equipment just because it falls into the water or if a power head cord is leaking current into the water. What it will (hopefully) prevent is you getting a shock from the leaky or faulty electrical equipment. Basically current flows from the hot wire then to the equipment and then back through the neutral wire. The gfci looks at the current flowing from the hot wire and the neutral wire. If the two numbers have a difference of greater then like 4 or 5 milliamperes then the gfci opens and prevents further current to the equipment. The reason why the gfci doesn't trip when current strays from the wires (it's intended path) is because the current still returns back to the neutral through the water. The gfci doesn't care where the current goes as long as it returns. You don't want to provide a path for the current to go to ground. In other words you stick your hand in the water and your bare foot. You now have provided a path for the current to go to ground. Now the gfci senses a difference from the current leaving the hot wire and what current is returning, if any, through the neutral wire in the gfci unit. It then trips. But in the previous example the gfci would not trip if the halide light fell into the tank, unless the halide was case grounded. If the halide light was case grounded the current would want to go to ground and a difference in current would be sensed and then the gfci would trip. Is it a good idea to have equipment that goes in water gfci protected, I would say yes. Is it going to protect you from a shock. Hypothetically yes. Well it should. I wouldn't want to be the test dummy to see if it works. I put faith in the fact that it works. Now do you need to buy another one depends on how it's wired. You can install a gfci outlet on the first string of outlets and the gfci will protect all the outlets down stream of the gfci. If this pump is going on a circuit that's different then the one you have the gfci already installed then yes you need another one. I quick and easy way to test to find out is to plug the pump into the outlet and then trip the gfci. They are marked "test" and "reset". When you push the "test" button the pump might turn off. If the pump turns off then the gfci protects that outlet. If it does not then that gfci does not protect this outlet. Be aware though that if that gfci does protect other outlets it will interrupt what ever is plugged into them.

03/31/2014, 06:28 PM	#6
tufkab Registered Member Join Date: May 2011 Location: Ontario, Canada Posts: 178	madean; please educate yourself further before giving others dangerous advice. A halide, specifically one with a magnetic ballast can kill you even plugged in to a GFCI. Magnetic ballasts have no electrical connection between the input and the output. The only time that a magnetic ballast would ever trip a GFCI is basically a winding shorted to the case. On the output side, you could short the connection or even hook a phase straight to ground and the GFCI would not see anything. The magic of induced current ! As far as a GFCI for a DC motor; Not likely. The DC voltages and currents we're talking about don't really pose much of a danger. GFCI outlets have their place; but you have to understand their limitations, a false sense of protection is the most dangerous part of working with electricity.