220 Volt GFI ??

[aswetich]

Why would a 220 Volt pool pump not have a GFI breaker like everything else ? Does it have to do with the swimming pool bonding ? I also have a 220 Volt sprinkler pump that pumps from the lake that also does not have a GFI. All my electrical was installed professionaly and inspected so it must be OK.

Thanks

 

[JasonLion]

If it is hardwired (no outlet) then the pump doesn't have to have a GFI (in most of the US), though one is frequently provided anyway. I had a couple of service people who refused to work on my pool until we put in the GFI, even though it was hardwired.

 

[ric]

Hi aswetich
I would say your local code doesn't require it. My local code doesnt but I did install them any way on my heater,pump and spa.

 

[aswetich]

Thanks

Just to be safe I will probably add them.

 

[chatcher]

Adding one won't hurt anything, but...

Can you dream up a hypothetical scenario in which it will do anything to improve safety, even slightly?

The rationale behind the requirement for a GFCI for a receptacle used by a pump is that someone could disconnect the pump and connect some other device that could potentially be unsafe without one. That can't happen with a hard-wired pump.

 

[JasonLion]

All of the situations that a GFI will help you in are very unlikely, but they do exist. A hot to ground short inside the pump will run 220 volts into the pool water. Such a short would probably trip a regular circuit breaker, but maybe not. It will always trip a GFI.

 

[chatcher]

All of the situations that a GFI will help you in are very unlikely, but they do exist. A hot to ground short inside the pump will run 220 volts into the pool water. Such a short would probably trip a regular circuit breaker, but maybe not. It will always trip a GFI.

I don't buy it. A single point cannot be at two different electrical potentials at the same time. Either the pump case is at ground potential, or it isn't. A "hot to ground short" is a very brief event and if the circuit breaker doesn't open the next weakest link in the circuit will. But let's say the ground wire from the panel to the pump is broken, and the pump case is no longer at ground potential. And let's say one hot leg of the 220-volt circuit to the pump is somehow shorted to the pump case, and the case is now at 110 volts with respect to ground. And let's say the bonding wire is connected from the pump case to the metal grid surrounding the pool, yet broken at all the places where it would normally be connected to the electrical circuit ground, like the heater, SWG, and pool light. And let's say the pool and everyone in it is now at 110 volts potential with respect to the electrical circuit ground. No current flows through anyone and nobody gets shocked because everything in and around the pool is at the same electrical potential. Just like a bird perched on a high voltage wire. This is an extremely unlikely combination of failures, yet no GFCI is needed to save us. For someone to fry they need to physically bridge two points at different electrical potentials. You could easily do it by using a defective hair dryer while standing in your pool. In that case depending on a GFCI to save you might even be risky.

 

[JasonLion]

All it takes is a little resistance between the hot wire and the case, 5 or 6 ohms would probably do it, and a regular breaker won't trip. You then get a loop between hot and ground across the pump casing with the pump casing ending up at some intermediate voltage due to resistance in the various wires involved.

As you say, no one in the pool is directly at risk (assuming the bonding system is working), because they are at a uniform potential. But that first step off the deck onto dirt might cause a problem for wet bare feet.

But go on from there and say that the bonding wire to the pump is missing and there aren't any other connections between electrical ground and the bonding system. I have seen that more than once. Then there is a circuit from the pump casing through the water to anything metal, say a ladder, and back through the earth to the local electrical ground. Plus, it doesn't take nearly as much voltage to hurt you when you are wet as compared to dry, so it could possibly be fatal.

A GFI is specifically designed to break a short from hot to ground through a human body before the human is injured. They don't work 100% of the time, but they do work almost always.

Each of these failures is very unlikely. Everything coming together just so to kill someone is really really unlikely. But it could happen, and across all the pools in the world it probably has happened at least once.

I would rather have the chance of death be lower rather than higher. For less than $100 for parts a GFI breaker will reduce the odds of wiring failures killing me by perhaps 100 times. That sounds like a good buy to me, even if the original odds are very very low already. (The installed cost of adding a GFI could be far higher.)

 

[chatcher]

All it takes is a little resistance between the hot wire and the case, 5 or 6 ohms would probably do it, and a regular breaker won't trip. You then get a loop between hot and ground across the pump casing with the pump casing ending up at some intermediate voltage due to resistance in the various wires involved...

...and say that the bonding wire to the pump is missing and there aren't any other connections between electrical ground and the bonding system... ...Then there is a circuit from the pump casing through the water to anything metal, say a ladder, and back through the earth to the local electrical ground.

I don't want to belabor the point unnecessarily, but to continue with your example, there is electrical current somehow flowing from the faulty pump into the water in the pump housing, through the pool plumbing, into the water in the pool. And the path of the current flow is from there to the earth through a ladder, and from there through the earth to the electrical ground. The maximum potential at the hot wire is 110 volts nominal. (It is difficult to imagine a scenario where anyone in a pool might be exposed to 220 volts - it would require both hot wires to be connected to different parts of the pool. But if one wire did become connected to the water in the piping, and the other to the bonding system of the pool, and the swimmer was the only connection between the two, then the GFCI would not be of any help since it cannot prevent a shock between the two hot wires, only between a hot wire and ground. But I digress.) There are all kinds of resistances in the proposed scenario, your 5 or 6 ohm "short", the water itself which, even loaded with salt, is far from a good conductor, and the not inconsiderable resistance through the earth itself to the electrical service ground rod(s). This resistance limits the current flowing in the system, and the voltage drop across each resistance reduces the voltage. The metal ladder is a better conductor than the water or the earth, and connects the two, meaining there is virtually no local difference of potential between a swimmer in the water and the ladder or the deck it is attached to.

The bonding system of the pool is by far the most important electrical safety consideration. If concerns about a defective bonding system are the motivation to add a GFCI to the pool pump, then what about the many other more likely sources of potentially lethal voltages that can affect our pools? Ignoring lightning, overhead power lines, the shorted well pump leaking current into the garden hose, and the shorted sewage transfer pump up the street leaking current back through the waste line, just consider stray voltage in the ground near the pool. The ground itself is often "energized" and the sources of the voltage can be difficult to find. Maybe the neutral circuit in your next door neighbor's house is leaking current into the ground through their ground rod (maybe their ground rod is closer to your pool than your ground rod). Maybe your neighbor's pool pump is shorted and current is flowing from it through his pool into the ground near your pool. If your bonding system is broken you are at risk regardless of how many GFCI breakers you have.

I guess for a very far-fetched, yet definitive, answer for whether purchasers of 220-volt GFCI breakers are getting "pool stored", we would need some calculations. Assume a 110-volt (or let's say 130-volt, for worst case conditions) hot wire is connected inside one end of a water-filled pipe. Assume the conductivity of the water is as high as a swimming pool gets, with high salt and other mineral levels. Assume the pipe is as short as is found in typical swimming pool installations. Assume the other end of the pipe is connected to a container filled with the same water, and a swimmer is standing chest deep in the water. The swimmer holds in his hand, outside the container a bare copper conductor connected directly to electrical ground. Is the potential voltage difference across the swimmer's body high enough to make him regret volunteering for the experiment?

 

[JohnT]

Adding one won't hurt anything, but...

Can you dream up a hypothetical scenario in which it will do anything to improve safety, even slightly?

The rationale behind the requirement for a GFCI for a receptacle used by a pump is that someone could disconnect the pump and connect some other device that could potentially be unsafe without one. That can't happen with a hard-wired pump.

First, you start with an electrician who doesn't understand pool bonding. Add a broken or loose ground wire and a broken pipe spewing gallons of water in the vicinity of the pump, and you are pretty close. I agree it is an unlikely scenario, but I've seen some really bad wiring jobs, even by alleged pros, and would estimate that 75% of pools are improperly bonded. Outside wiring is 100% GFCI protected for me, if for no other reason than to protect me from my own stupidity.

 

[JasonLion]

It doesn't take anything near 220 volts to kill you when you are wet! A properly installed GFCI is the single most effective thing you can do to reduce the risk of electrocution. Of course making sure the bonding system is properly installed is also important. The difference is that you can tell if there is a GFCI breaker installed or not while it will probably take a professional to tell you if your bonding system is working correctly.

 

[chatcher]

It doesn't take anything near 220 volts to kill you when you are wet! A properly installed GFCI is the single most effective thing you can do to reduce the risk of electrocution. Of course making sure the bonding system is properly installed is also important. The difference is that you can tell if there is a GFCI breaker installed or not while it will probably take a professional to tell you if your bonding system is working correctly.

No, 30 volts is enough to kill a human under the right circumstances.

GFCI's provide pretty good protection under the limited set of conditions for which they were designed, namely faults that cause electrical current to flow to ground rather than back through the normal circuit return path. They do nothing at all to prevent electrocution when electricity is flowing through the normal path. Grab both hot leads of a 220-volt GFCI circuit and the GFCI won't trip. Grab the hot lead and the neutral lead of a 110-volt GFCI circuit and the GFCI won't trip. GFCI protection is a useful tool, but it is no panacea, and no substitute for proper bonding of the pool.

The NEC does not require GFCI protection for permanently wired pool pumps. Although some details in the NEC do not make a lot of sense, it generally does a good job laying out the requirements for electrical safety. Each section of the code does rely on adherence to the other sections. Adding something which is not required (GFCI) to compensate for the lack of something that is required (proper bonding) does not address the problem and won't satisfy the code.

I have no problem at all with anyone installing GFCI's wherever they want them, but they should do so with the knowledge of exactly what they can and cannot do.

 

[JasonLion]

Adding something which is not required (GFCI) to compensate for the lack of something that is required (proper bonding) does not address the problem and won't satisfy the code.

Of course it won't satisfy the code! How exactly is the average pool owner supposed to satisfy the code? I hire licenced electricians to work on my pool and they get the bonding wrong sometimes. Most people would have no way of checking that. Looking around at pools I see the bonding is sometimes wrong. Presumably most of them used licenced electricians. Is the pool owner supposed to hire ten electricians and have them vote on their evaluation of the bonding system?

More than half of the point of the way the NEC is written is to protect from multiple points of failure. The more layers of defense you can have the better. No mater what the state of the bonding system, adding a GFCI (if you don't already have one) will increase your safety. This is about the only physical upgrade the average pool owner can do to improve the electrical safety of their pool.

Most pool electrocutions are caused by pool lights. Pool lights are required to have a GFCI. Almost all of those deaths are in situations where the GFCI was missing. The average pool owner can tell if there is a GFCI installed or not and if not they need to have one installed. Better to put one on the pump as well because who knows what else is wired to the same circuit (code or no code) and the pool owner may well have the pump and the light circuits mixed up. If we take care of some of the extrememly unlikely possibilities involving shorts inside the pump motor at the same time all the better.

The one caveat is that there are some rather rare situations where the pump won't work when a GFCI is installed. This can happen when there are strong currents flowing in the earth. That is why the code doesn't require a GFCI. If you get into that situation there are additional risks. I think you are much better off knowing about it, learning as much as you can about the risks, and talking to your electric utility to find out if they can fix the situation. Trying to install a GFCI will uncover these problems and give you a chance to try and get them resolved.

 

[chatcher]

...Is the pool owner supposed to hire ten electricians and have them vote on their evaluation of the bonding system?

Probably not a good idea - the one or two that got it right would be outvoted! And that's no joke. The percentage of working electricians who can accurately explain the differences between bond, ground, and earth must be very small.

No mater what the state of the bonding system, adding a GFCI (if you don't already have one) will increase your safety.

And maybe give you a false sense of security...

Pool lights are required to have a GFCI.

They need them. And even with the GFCI, there is a plausible scenario in which you could be electrocuted by a broken pool light, wired exactly according to code and best practices. Best not to fiddle with the light while swimming.

Better to put one on the pump as well because who knows what else is wired to the same circuit (code or no code) and the pool owner may well have the pump and the light circuits mixed up.

We better put GFCI's on every circuit in the house! Hey, those heating elements in the water heater are energized and actually touching the water! That electricity could run through the copper pipes to my bathtub faucet - I better keep my big toe away from that from now on...

 

[Lenny]

chatcher is right. If there is a short circuit in the pump, there's no way current would travel into the pool. I have a pretty good amount of experience in the electrical field.

The important thing is that the pool equipment is all solidly grounded. If you are really concerned about safety, turn off the breakers and then check all ground connections for tightness. I found a bad ground connection in my pool equipment that the builder forgot to tighten. If you're really, really concerned, use a meter to check continuity from all equipment (pump housing, etc) back to the panel ground and ground rod. If you're really, really, really worried, have someone come in and do a ground test. Fact is, you really don't know for sure that anything is grounded without a ground test. Just because you drive a ground rod in the ground doesn't mean that it provides adequately low ground resistance. But this testing would not be cheap ;-).

All lighting and receptacles have to be GFCI protected. If the rest of the equipment is solidly grounded you don't have to worry.

 

[JasonLion]

chatcher is right. If there is a short circuit in the pump, there's no way current would travel into the pool. I have a pretty good amount of experience in the electrical field.

No single failure will do it. I can't think of any double failures that would do it, though it seems plausible that there could be one. Several of the double failures energize the boding grid relative to earth, which isn't as bad but isn't good either. A triple failure would do it easily. Hot wire shorts to chassis, ground is not connected, pump is not bonded. 120 volts flows from the hot wire through the pump chassis, to water, through the water, to the ladders, to the bonding grid, to earth.

Triple failures are very very very uncommon but across all pools they do happen once in a while. I have seen each of the single failures in the triple case I just described actually happen on different pools. The odds against all three happening at once are astronomical, but they are not zero. Feel free to decide that those odds don't bother you, but don't say that it is impossible.

 

[kevreh]

This has been an interesting and informative thread to read. Looks like NEC has changed its stance on GFCI and pool pumps (you now need them regardless if plugged in or hardwired).

http://www.iaei.org/magazine/2009/06/gf ... tural-fit/

Kevin

 

[CraigMW]

Kevin is right. The NEC has required GFCI protection of hard-wired pool pumps since before 2009:

Pool Pump Motors

According to 680.22(B), all 15- or 20-ampere, 125-volt or 240-volt, single-phase outlets supplying pool pump motors are required to be provided with ground-fault circuit-interrupter protection for personnel. GFCI protection for pool pump motors is required whether supplied by receptacle or direct connection. GFCI protection for pool pump motors has not always been required for a direct connection, but the NEC now requires GFCI protection for these motors whether cord-and-plug connected or hard-wired. It should be noted that 680.22(B) applies to these pool pump motor outlets regardless of their location from the inside edge of the swimming pool.

At least part of that requirement may be for personnel protection, i.e. anyone touching the pump while standing on a wet equipment pad could be vulnerable to electrocution. BTW, I thought GFCI's detected current leakage between the line and neutral (for a 120V) or leakage between two legs of a 220V line. Regardless, for a few extra bucks, I don't mind staying in code on this. Who am I to argue with the PhD level electrical engineers who write the NEC anyway?

 

[CraigMW]

Re:

GFCI's provide pretty good protection under the limited set of conditions for which they were designed, namely faults that cause electrical current to flow to ground rather than back through the normal circuit return path. They do nothing at all to prevent electrocution when electricity is flowing through the normal path. Grab both hot leads of a 220-volt GFCI circuit and the GFCI won't trip. Grab the hot lead and the neutral lead of a 110-volt GFCI circuit and the GFCI won't trip. GFCI protection is a useful tool, but it is no panacea, and no substitute for proper bonding of the pool.

The NEC does not require GFCI protection for permanently wired pool pumps. Although some details in the NEC do not make a lot of sense, it generally does a good job laying out the requirements for electrical safety. Each section of the code does rely on adherence to the other sections. Adding something which is not required (GFCI) to compensate for the lack of something that is required (proper bonding) does not address the problem and won't satisfy the code.

I have no problem at all with anyone installing GFCI's wherever they want them, but they should do so with the knowledge of exactly what they can and cannot do.

No, again GFCI's do not detect flow to ground. They detect the current imbalance between the line and the flow back to neutral, or the imbalance between 120V legs in a 220V circuit.

http://en.wikipedia.org/wiki/GFCI

Also, assuming worst case scenario (e.g. copper piping and a metal pump): if someone touches the return and a grounded (or bonded) metal ladder, the current to consider is based on resistance/impedance through the body between two arms. This is estimated to be roughly 750-1000 ohms with wet skin in direct contact with metal. So:

I=V/R, so I=120/1000= 120mA. This is significantly beyond what is required to pop a typical GFCI (which is rated to disconnect the circuit at 5-6 mA). This is also beyond what it takes to cause electrocution (roughly 60 mA AC), or induce loss of muscle control (and likely drowning).