thhw
- Thread starter frank
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txsparky
Member
- Location
- Conroe, Texas
Re: thhw
Rick,
If Frank is talking about running the wire inside a conduit, what would be the difference? In most underground installations,( at least where I'm at ),the conduits are filled with water,and the wire is submerged !
[ April 24, 2003, 08:33 PM: Message edited by: txsparky ]
Rick,
If Frank is talking about running the wire inside a conduit, what would be the difference? In most underground installations,( at least where I'm at ),the conduits are filled with water,and the wire is submerged !
[ April 24, 2003, 08:33 PM: Message edited by: txsparky ]
- Location
- Illinois
- Occupation
- retired electrician
Re: thhw
Rick,
I don't find a general use submersible cable in the white book. What type of cable do you have in mind? Also the UL White Book says that a wet location is an "area subject to saturation with water". How is this different from "submerged"?
Don
Rick,
I don't find a general use submersible cable in the white book. What type of cable do you have in mind? Also the UL White Book says that a wet location is an "area subject to saturation with water". How is this different from "submerged"?
Don
- Location
- Bremerton, Washington
- Occupation
- Master Electrician
Re: thhw
That reminds me I have an application with a floating pump on a floating water reservoir cover. Its an acre in size, the pump is fed with SO cord. I didn't install this one, the one before I did, I used well cable in LTFNMC.
Its basically a big water bed. Interesting to walk on, especially when the pump floats hang up and there is a lot of water on the cover.
That reminds me I have an application with a floating pump on a floating water reservoir cover. Its an acre in size, the pump is fed with SO cord. I didn't install this one, the one before I did, I used well cable in LTFNMC.
Its basically a big water bed. Interesting to walk on, especially when the pump floats hang up and there is a lot of water on the cover.
rick5280
Senior Member
Re: thhw
Respectfully, a close reading of the UL white book will turn up a few items not mentioned here, or glossed over.
Point 1: UL's definition of wet location: "Installations underground or in concrete slabs or masonry in direct contact with the earth, and locations subject to saturation with water or other liquids, such as vehicle washing areas, and locations exposed to weather and unprotected."
Nowhere in the definition is the wording, under water, included, and I find it hard to draw that from the definition. I don't think one could say that a vehicle washing area is under water, can one?
Point 2: UL's section for Flexible Cord (ZJCZ) has wording which includes this: " Additional Markings: "Water Resistant" - indicated that the cord is suitable for immersion in water."
This states that any cord listed in the section, when including this additonal marking on it cover, can be used in water.
Point 3: UL's section for Thermoplastic-Insulated (ZLGR) contains no such wording.
My thinking on this that since this section has no requirement for this additional marking, no conductor listed in this section can be used in such an area (under water).
Are all underground raceways full of water? I hope not. Does water sometimes get into it? Unfortunatly, yes. Will the conductors fail? I believe in time they will. Are the amp ratings of the conductors different when in water? YES.
Again, I respect all who post here.
Rick Miell
Respectfully, a close reading of the UL white book will turn up a few items not mentioned here, or glossed over.
Point 1: UL's definition of wet location: "Installations underground or in concrete slabs or masonry in direct contact with the earth, and locations subject to saturation with water or other liquids, such as vehicle washing areas, and locations exposed to weather and unprotected."
Nowhere in the definition is the wording, under water, included, and I find it hard to draw that from the definition. I don't think one could say that a vehicle washing area is under water, can one?
Point 2: UL's section for Flexible Cord (ZJCZ) has wording which includes this: " Additional Markings: "Water Resistant" - indicated that the cord is suitable for immersion in water."
This states that any cord listed in the section, when including this additonal marking on it cover, can be used in water.
Point 3: UL's section for Thermoplastic-Insulated (ZLGR) contains no such wording.
My thinking on this that since this section has no requirement for this additional marking, no conductor listed in this section can be used in such an area (under water).
Are all underground raceways full of water? I hope not. Does water sometimes get into it? Unfortunatly, yes. Will the conductors fail? I believe in time they will. Are the amp ratings of the conductors different when in water? YES.
Again, I respect all who post here.
Rick Miell
txsparky
Member
- Location
- Conroe, Texas
Re: thhw
They are in my neck of the woods.
- Location
- Massachusetts
Re: thhw
Surprisingly many run fine this way.
Edit: Not trying to give you a hard time Rick, just trying to point out in some areas raceways full of water are the norm.
[ April 26, 2003, 09:12 AM: Message edited by: iwire ]
I would say the majority of the underground raceways in my area have at least the low spots if not the whole length "submerged"
Surprisingly many run fine this way.
Edit: Not trying to give you a hard time Rick, just trying to point out in some areas raceways full of water are the norm.
[ April 26, 2003, 09:12 AM: Message edited by: iwire ]
- Location
- Illinois
- Occupation
- retired electrician
Re: thhw
There are very very few underground conduits in this area that are not normally water filled. To me "subject to saturation with water" includes submerged. I think that the conduits in or blelow the slab in a "vehicle washing area" would normally be filled with water. I still find no general use cable listing in the white book that includes the word "submerged". Yes, it does appear for well pump cable and for the flexible cable, but not for conductors that installed in raceways.
Don
There are very very few underground conduits in this area that are not normally water filled. To me "subject to saturation with water" includes submerged. I think that the conduits in or blelow the slab in a "vehicle washing area" would normally be filled with water. I still find no general use cable listing in the white book that includes the word "submerged". Yes, it does appear for well pump cable and for the flexible cable, but not for conductors that installed in raceways.
Don
Re: thhw
As usual I have a different interpretation of the definition of a wet location. To me, the conduit is the only material in a wet location. The conduit is to prevent the wiring from being in a wet location. The wiring is not in contact with the earth, as required in the definition to qualify as a wet location.
Underground conduits and ducts under the jurisdiction of the NESC, are installed according to NEMA Bulletin No. TCB2. The requirement for installation will not permit water to remain in the conduit. The classification of the interior of the conduit, worst case would be a damp location.
Grading, and drain holes at low spots will prevent the water from remaining for a prolonged time.
As usual I have a different interpretation of the definition of a wet location. To me, the conduit is the only material in a wet location. The conduit is to prevent the wiring from being in a wet location. The wiring is not in contact with the earth, as required in the definition to qualify as a wet location.
Underground conduits and ducts under the jurisdiction of the NESC, are installed according to NEMA Bulletin No. TCB2. The requirement for installation will not permit water to remain in the conduit. The classification of the interior of the conduit, worst case would be a damp location.
Grading, and drain holes at low spots will prevent the water from remaining for a prolonged time.
- Location
- Illinois
- Occupation
- retired electrician
Re: thhw
Bennie,
What wire type is listed for use in raceways that will be filled with water? I don't see any in the white book.
Don
Note: I just reread Bennie's post and saw that it was refering to the NESC code, and I've never worked on a projected that was designed to that code.
[ April 26, 2003, 11:13 AM: Message edited by: don_resqcapt19 ]
Bennie,
That type of installation does not happen on most real world jobs. Maybe on large heavily engineered jobs that would happen, but I've never seen a drawing for a project that I have installed that called out a drainage slope for the conduits, and the amount of engineering provided by the designer seems to be getting less and less each year. I have seen drawings from installations that were made before I entered the trade that called for drainage of underground raceways, but never for a job that I have installed. Also with the smaller pipe sizes, the PVC follows the ditch and couple of changes in elevation equal to or greater than the diameter of the conduit will create a "trap effect" and the water will never drain out on its own.
What wire type is listed for use in raceways that will be filled with water? I don't see any in the white book.
Don
Note: I just reread Bennie's post and saw that it was refering to the NESC code, and I've never worked on a projected that was designed to that code.
[ April 26, 2003, 11:13 AM: Message edited by: don_resqcapt19 ]
- Location
- Massachusetts
Re: thhw
The POCO in Boston has water pump crews just to pump out the manholes that are full of water when the other crews have to work in them.
Much of Boston is only little above sealevel as much of it was ocean that was back filled.
But when you are below the water table "drain holes" become "fill holes"
The POCO in Boston has water pump crews just to pump out the manholes that are full of water when the other crews have to work in them.
Much of Boston is only little above sealevel as much of it was ocean that was back filled.
- Location
- Illinois
- Occupation
- retired electrician
Re: thhw
Bennie,
Don
[ April 26, 2003, 11:17 AM: Message edited by: don_resqcapt19 ]
Bennie,
At a local industrial plant the 5 kV underground raceways are almost always filled with water. The cables are not "submarine rated" and most are over 20 years old. The manufacturer's information indicates that the expected life of these cables is 25 to 35 years. They are also not lead sheathed cables. I understand that many experienced power engineers maintain that the only truly waterproof cable jacket is lead.
Don
[ April 26, 2003, 11:17 AM: Message edited by: don_resqcapt19 ]
- Location
- Massachusetts
Re: thhw
Don, the job I am on now tells me to pitch the raceways 1/4" per foot to drain, but as this is one inch RNC for site lights this is not going to happen for exactly the reason you stated it follows the trench.
They is no way I would get the excavators to produce a "perfect trench" that would have a tolerance of less than 1" :roll:
Don, the job I am on now tells me to pitch the raceways 1/4" per foot to drain, but as this is one inch RNC for site lights this is not going to happen for exactly the reason you stated it follows the trench.
They is no way I would get the excavators to produce a "perfect trench" that would have a tolerance of less than 1" :roll:
frenchelectrican
Senior Member
- Location
- Nord'est Wisconsin et Paris France
Re: thhw
yeah bennie i can get your point about using the undergound cable that can be approved for with sumgred in the water but i hate to ask you beannie and iwire(bob) there are a cable companie that make specal appaction for that kind of use i try to find few companines and they dont have that type of cable for useage so if you guy can find it i will be glad to hear that
merci marc
yeah bennie i can get your point about using the undergound cable that can be approved for with sumgred in the water but i hate to ask you beannie and iwire(bob) there are a cable companie that make specal appaction for that kind of use i try to find few companines and they dont have that type of cable for useage so if you guy can find it i will be glad to hear that
merci marc
- Location
- Massachusetts
Re: thhw
When I first got started in the trade I was shocked to find the raceways full of water and I thought it was something we should fix immediately. But after seeing this so often it does not worry me in the least, yes I would think not submerged would be better but that is not what really happens (at least in this area).
It has been my experience that as long as the wires are not nicked or damaged on the installation and are rated wet location they survive no problem.
We do replace a lot of conductors in Walkerduct that get exposed to wax stripper from the floor cleaners in a super market chain we work for, it seems the wax stripper eats the THWN.
Believe me when I say you can get some impressive flames out of a 2" Walkerduct access when 15 to 20 120/208 circuits start shorting together!
When I first got started in the trade I was shocked
to find the raceways full of water and I thought it was something we should fix immediately. But after seeing this so often it does not worry me in the least, yes I would think not submerged would be better but that is not what really happens (at least in this area).It has been my experience that as long as the wires are not nicked or damaged on the installation and are rated wet location they survive no problem.
We do replace a lot of conductors in Walkerduct that get exposed to wax stripper from the floor cleaners in a super market chain we work for, it seems the wax stripper eats the THWN.
Believe me when I say you can get some impressive flames out of a 2" Walkerduct access when 15 to 20 120/208 circuits start shorting together!
frenchelectrican
Senior Member
- Location
- Nord'est Wisconsin et Paris France
Re: thhw
hi bob;
did you say wax stripper did eat the thwn insluation cover ??? that gotta be a strong one sound like a acid base stripper to me. unforetly i did see the fair share of shocker what you see with wax stripper the last one i have it was dripping on floor box and if course it was not walker brand look like "oz - (something i cant read it all it was etched off from stripper) and drip on wire way and hit the xlp wire ( super tough plastic sameone used for direct burial appaction) and blew the 480 volts conducters to smithes ( i cant repeat my french swearing in here so i keep respect in here ) and i learn that wax stripper did drip into open crack of wireway and left a mess it took me 3 day job to repair all of the mess and including replace 800 amp breaker !!!!!!!! sorry for getting off my point but back to the point i do agree with you bob about the conducts with filled with water but only thing i dont like it here i am sure you have the same probem is winter time when try to replace the conducters it do get frozen up ( i have pretty deep frost here in state of wisconsin )
merci ( thanks ) for your time to hear this one
marc
hi bob;
did you say wax stripper did eat the thwn insluation cover ??? that gotta be a strong one sound like a acid base stripper to me. unforetly i did see the fair share of shocker what you see with wax stripper the last one i have it was dripping on floor box and if course it was not walker brand look like "oz - (something i cant read it all it was etched off from stripper) and drip on wire way and hit the xlp wire ( super tough plastic sameone used for direct burial appaction) and blew the 480 volts conducters to smithes ( i cant repeat my french swearing in here so i keep respect in here ) and i learn that wax stripper did drip into open crack of wireway and left a mess it took me 3 day job to repair all of the mess and including replace 800 amp breaker !!!!!!!! sorry for getting off my point but back to the point i do agree with you bob about the conducts with filled with water but only thing i dont like it here i am sure you have the same probem is winter time when try to replace the conducters it do get frozen up ( i have pretty deep frost here in state of wisconsin )
merci ( thanks ) for your time to hear this one
marc
hurk27
Senior Member
- Location
- Portage, Indiana NEC: 2008
Re: thhw
Wax stripper is not an acid base product it is a chemical base solvent and will dissolve plastic components of the wire coating acid is water base and in most situations it will not harm the coating on wire. this is why bleach is not the thing to try to get grease out of clothes, as bleach is also water based.
We had anodizeing tanks where I use to work at Florida Extrusion in sanford, Florida the anode wires use to hang in the acid all the time and never caused a problem unless the insulation had a crack in it.
Wax stripper is not an acid base product it is a chemical base solvent and will dissolve plastic components of the wire coating acid is water base and in most situations it will not harm the coating on wire. this is why bleach is not the thing to try to get grease out of clothes, as bleach is also water based.
We had anodizeing tanks where I use to work at Florida Extrusion in sanford, Florida the anode wires use to hang in the acid all the time and never caused a problem unless the insulation had a crack in it.
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