?sleeve?

[Anonymous]

If I understand right? You're not allowed to run Uf cable in pipe, be it t/w,rid,Imc or Pvc under any conditions(according to NEC) but you can use as a sleeve, for protection? I have seen it used on furnaces where the romex is sleeved from ceiling joist down to junc box or entering garage from a underground run with uf cable? Certain there are many other situations where this is allowed or where common sence may wish to superseed NEC. Have hard time leaving something rest,if not fully understood! What i"m trying to get at here is, when wiring hot tub was unable to use 6/3 w/Grng uf cable. (used pvc, seperate wires.) Again, couldn't have pulled the UF cable pemanently in conduit underground, because EGC not insulated and Uf cable itself only provides protection,as would the conduit also.( my interpritation of ruling) May be bumping heads here with probably 2 code requirements. Therefore because of possible stray voltage your not allowed to use Uf cable for HOT TUBS outside!Run underground. Are these voltages high or is it just a potential that someone with heart condition lets say could suffer from them. Sorry for taking your time on this but sure would like an explanation that would clear my mind. Talked with an electrician that hadn't heard of this and thats what triggered my follow up question on this matter. Besides I have 70' of unused uf cable hanging in our basement. TY

[Wgoodrich]

The NEC does not forbid nonmetallic sheathed cable or UF cable from being installed in a conduit. The NEC even provides rules for conduit fill limitation calculations concerning rules to ensure against overfilling a conduit when installing nonmetallic sheathed cable in a conduit.

What you have is a specialty application that does not coincide with the rules of Chapters 1 through 3 of the NEC that are concerning normal wiring.

Hot tubs rules are found in Chapter 6 of hte NEC due to the mixing of water and electricity needing extra precaution against creating a difference of potential concerning grounding and noncurrent carrying metallic parts.

While electricity is not considered a good conductor of electricity, the impurities found in water such as iron etc. is considered a conductor of electricity. Problem is so many people get in and out of pools and hot tubs the conductivity of the water in pools and hot tubs can change rapidly. Then considering the fact that a wet electrical connection tends to be more unreliable due the changing from real poor connection to a real good connection then back to a real poor connection all due to the water or moisture being present with that connection. Water creates kind of like an unpredictable child near deep water. Will that child jump in or not. One day that child surely will jump in but next time that same child will surely not jump in. Would you risk not going after that child taking for granted today that child would not jump in? Same problem arises with water. One day the water won't conduct electricity. May even be one month or one year that water won't conductor electricity all depending on the amount of saturation and types of impurities in that water in that hot tub, fountain, or pool. During all this time electricity may have been shorted to this water yet nothing happened because there is no conductivity in the water. Then one day someone jumped in stirring up certain impurities or that person had certain impurities on his or her body when they jumped in. Now we have the right conditions WITHOUT WARNING that will make that water a perfect conductor of electricity. The short introducing elctricity in that water [whether leaked through the earth or due to a bad rubber seal on a light in the pool or any other major list of places electricity could introduced into that water of that hot tub or pool. Nothing happened for possibly even years with this electricity introduced into the water because the conditions were not right concering impurities in that water to promote the water to be a conductor of electricity. Then that one person that jumped in changed or added certain impurities into the water and BANG we have a perfect conductor of electricity being that same water. You may be swimming in that water at the time and you WON'T know you have become energized because you are the same as a bird sitting on a high voltage wire with nowhere for the electricity to go from that hot wire through that bird. Then you swim over to a metal ladder or other noncurrent carrying metallic part that has a GOOD path to ground. The minute you touch that good path to ground you become THE conductor creating the path to ground from that energized water.

By now you should have a picture in your mind that the water is like that unperdictable child near deep water. You will never have warning that the water changed conductivity setting up a harmful and often fatal shock even if you are in the water when this change happens. That is until you touch a GOOD path to ground. Then you may know it painfully well but then you may never know anything again EVER.

The NEC recognizes the hazards discribed above by writing an article with special wiring requirments in an attempt to try and prevent difference of potential being present in a pool or hot tub's water and associated equipment whether metal or not.

Please be aware that there are what is called transient voltages in the earth constantly at different changing levels of power. You could have a pool of water with no electrical equipment connected or associated with this pool of water you are swimming in. Those transient voltage even in the earth can introduce into that non electrical pool and create a safety hazard of shock even in that nonelectrical pool.

This knowledge prompted what is called the BONDING GRID system that is designed to ensure all pieces of noncurrent carrying metal 4" square or larger is bonded together to avoid any difference of potential where electricity can flow from energized to less energized conductive conditions. This bonding grid system's source it the pool or hot tub itself NOT the electrical system of the house. The intent of a bonding grid is to make all metals one entity of equal potential to eliminate the possibility for electricity to flow.

This knowledge of transient voltages, eddy currents, etc. where electricity can be in the air and in the earth for no certain reason known to you is why the NEC is requiring the green insulated equipment grounding conductor. Remember that the UF cable and nonmetallic sheathed cable does not have a green insulated equipment grounding conductor but only a COVERED grounding conductor where the plastic or rubber COVERING that equipment grounding conductor in that UF cable or nonmetallic sheathed cable is not recognized by the NEC nor tested by a certified testing labratory to be an acceptable insulation value as the green insulation on a green insulated grounding conductor has been tested and approved.

The NEC is aware of the transient voltages that can be introduced into a bare copper conductor installed in the ground especially if that nonmetallic sheathed cable or UF cable is knicked or otherwise unknowingly damaged allowing these transient voltages from many different sources to be introduced on that bare or covered equipment grounding conductor.

Then remembering that equipment grounding conductor is vital allowing a breaker to trip due to short circuit conditions that risk shocking people we have a delemma. If we install a bare or covered equipment grounding conductor in the earth then we risk transient voltages being introduced into the pool or hot tub water. Yet is we don't install that equipment grounding conductor with that branch circuit we risk a short circuit condition that may not trip the breaker making that water in that hot tub or pool energized.

Best thoughts of the NEC were to require a tested and listed insulated grounding conductor that is required to be green to depict this conductor to be an equipment grounding conductor. Then considering the risk of knicking this insulated wire then while outside the dwelling where the risk is greatest the rule was introduced not only to require the listed and tested green insulated equipment grouding conductor to protect from introduction of voltage onto the grounding conductor thus energizing the hot tub or pool's water but also introducing a further protective rule of while outside the dwelling this 12 awg equipment grouidng conductor must also be protected from damage by conduit protection.

It is not the intent of the NEC to forbid nonmetallic sheathed cable or UF cable from being installed in a conduit. YOu won't find that rule anywhere in chapters 1 through 3 of hte NEC. Any Chapters in the NEC after Chapter 3 are special conditions chapters. Chapter 6 of the NEC contains an article in 680 just for pools, hot tubs, fountains and the like mixing water and electricity designed for added concern in these type installations concerning a lot of the reasons mentioned in this reply and even reasons that didn't get mentioned.

Hope this helps

Wg

[Anonymous]

plan to read over. I think sometimes its best to accept a glass of water as a glass of water, not why is it a glass of water. I guess where I'm confussed and don't understand fully, is the fact I ran #8 bare from swing set (underground) to motor lug.(unprotected nothing) would seem this same as uncovered UF ground conductor. Apparently I'm missing something or to dumb to grasp. Good reason for name wannabe. Hey thanks much and will try to reread hopefully it will sink in!(but not when I'M in the tub.) What helps is Electrician I talked with wasn't aware either so I'm not alone.

[Anonymous]

In rereading, I feel I must remove bare # 8 and change to insulated #8 green run in pvc under the ground? correct. ty

[Wgoodrich]

Ty there are a lot of unknown when it comes to transient currents. The earth itself can create transient voltages same method as a battery produces transient voltages. Actually the whole world is full of transient voltages created through different methods by nature or human intervention. From anywhere as the right acid combiniation in the earth creating the battery affect to a car hitting a power pole causing a 7,200 volt wire or higher voltage to touch the earth thus introducing power into the earth to just earth movement somewhat like an earth quake creating massive pressure combined with friction that can also produce electricity into the earth. As you should now be able to see even mother nature can create these transient voltages and it wasn't even the fault of man kind. Transient voltages have been present since way before we knew there was such as thing as electricity.

You missed the key point of rule pThis. That key point of that bonding grid system's rules was that all pieces of metal associated [connected to] the pool and ALL PIECES OF NONCURRENT CARRYING METALLIC PARTS 4 INCH SQUARE OR LARGER LOCATED WITHIN 5 FEET OF THE POOL must be bonded together to create the pool's bonding grid system. NOTICE THE 5 FEET FROM POOL LIMITATION OF THIS BONDING GRID.

We do know quite a bit about transient voltages or power traveling through the earth by man made causes. For an example if emergency personel arrives at a scene of an accident involving a downed power pole, these emergency personel are normally trained to recognize certain types of power poles. If at the arrival on the scene it is seen that a single shorter style power pole is downed then chances are those wires are primary wires and safety should be attempted to avoid the emergency personel from being electrocuted by remaining approximately 100 ' or the normal distance of one pole length measured from pole to pole away from that point of contact of a live wire to earth. If upon arriving at the scene and they see a four legged steel tower then they suspect a transmission line that may have thousands of volts in contact with the earth then a distance of at least three normal power pole lenghts from pole to pole along the transmission line at point of contact with the earth should be maintained approximately 300'. Remember this is a loose discription don't risk your life on these distances if you approach an accident.

The reason I told the last paragraph is an attept to show the knowledge we do have approximately how far voltage will likely travel along the earth using the earth at a conductor. The 5' rule from the pool involving the bonding grid is our belief that normal transient voltages whether man made or mother nature made will travel approximately 5 feet through the earth at voltage levels that we expect may be present around pools. This 5 feet around the pool is where the goal is to make all metals 4 inch square or larger as one entity using this 8 awg copper solid conductor so that we can hopefully keep anyone swimming in that pool to be like that bird sitting on an energized prmary wire with nowhere for the current to flow using that bird as a conductor to complete the path for that current to flow. The bonding grid design is required to keep that person that may become energized wthout their knowing it from touching any metal that is of different potential from the potential of the water they are swimming in. ONce that person gets out of the water and is 5' from the pool then we consider that if the pool was energized in some manner that swimmer is far enough away now not to be concerned with the different potentials of metals from that point on they would be back to normal living.

Remember we are exposed unknowingly with these transient voltages continuously throughout or life. Proof is when you last touched a door knob and saw or felt a spark being static electricity created by you walking on just the right conditions creating that transient current.

Do not remove that 8 awg copper solid wire from being part of your bonding grid. That swing set from what you said is within the 5 feet from the hot tub being within this 5 feet area desired to be connected as one entity concerning metal parts to make up the bonding grid system.

The intent of the bonding grid system is to make a safe zone all being as one within 5 feet of that pool. Beyond the 5 feet from the pool or hot tub then you don't have to worry about because beyond the 5 feet is to be beyond the concerned and desired safe zone.

The wire coming from your house as power to the pool if with a bare or noninsulated wire can obsorb transient voltages no matter what the source of these transient voltages and carry then by way of that voltage obsorbing wire to the pool and introduce this voltage into the pool system without your ever doing a thing. May happen to day may happen a decade from now. This introducing stray voltages into the pool or hot tub is what we are trying to avoid by requiring that equipment grounding conductor connected to your electrical system and ran to the pool to be insulated and 12 awg. An insulated grounding conductor is limited much in its ability to obsorb any transient voltages where a bare wire would obsorb any transient voltages.


Hope this helps

Wg

[Anonymous]

thanks I think it finally sunk in! those strays could and may enter sytem by way of that unisulated equipment ground and the 5' grid protection will dispurse them or would equalise them,eliminating transfer from pool thru me to a grounded object .(within that 5' as explained) Darn hard for me to explain but hope now I got it close enough.. TY Very Much

[Wgoodrich]

Now you are getting the idea. The concern is protecting from energizing to pool but with the knowledge we have we may increase hazard unless we insulate from voltage being introduced from other sources [transient voltage] If that outside energy does enter the pool system then our goal is to provide it a return path to ground that can not be your body as the conductor. Much like a person walking up to a person and static spark occurs that they don't like. These two people know that static spark can occur while walking say across a carpet in dry weather so to prevent shocking each other they hold hands while in the house to make each other equal as one entity of potential thus avoiding the passing of voltage between each other. Whatever voltage builds in either person is equal in voltage to that person holding hands making each person as one entity equal in value. Just look at a pool or hot tub having all pieces of metal holding hands to eliminate as best we can to avoid that odd voltage that may at some time in the future from passing through our body to a return path to ground. If all pieces of noncurrent carrying metallic parts of a pool or hot tub are holding hands by way of the 8 awg copper bonding grid conductor then there is nothing that is not the same as touching one entity. If voltage enters the hot tub or pool system then it may find a return path to ground [center tap of the transformer most commonly] but it can't seek that return path through you because you are one entity with all other parts that can carry current.

Good luck

Wg

[Anonymous]

got it now! Thank you ever so much for the time and patience. Will hopefully keep future ?s on a more basic level. T's again :D

[Wgoodrich]

You asked a good question that many have trouble understanding or getting a picture in their mind as to the intent.

I suspect the discussion your created may have helped many to draw that picture in their mind as you have done.

You did good

Wg